text:
Rhaphidorrhynchium calliferum är en bladmossart som beskrevs av Fleischer 1923. Rhaphidorrhynchium calliferum ingår i släktet Rhaphidorrhynchium och familjen Sematophyllaceae. Inga underarter finns listade i Catalogue of Life.

Källor

Egentliga bladmossor
calliferum

redpajama_set_name: RedPajamaWikipedia


Ruan's Corner: WHAT'S IN A PHRASE - "MAKING WITH THE EYES"
The "wool is being pulled over your eyes" when you allow yourself to be inveigled into something. Inveigle comes from aveugle, French for blind, which goes back to oculus, the Latin word for eye (ab + oculus, without the use of your eyes).
If you "make eyes at a girl" or "give her the eye" you are ogling her. Ogle comes from the Dutch word for eye and is related both to the German word auge and the Latin oculus. A supercillious person is one who arches his eyebrows and looks down his nose at you; in other words, "a high-brow" who "high-hats" you. Supercillious is made up of super (above or high) and cillia (eyelids or eyebrows). A person who is haughty (French haut, high) is just "uppity."
If you "close your eyes to" something that you know is going to happen you are guilty of conniving, the literal meaning of which is "winking along with."
Ano naman po ang ibig sabihin ng "in a wink of an eye?"
How about "kahit kaunting pagtingin?"
Very informative! New phrase to live by.
Now I know the word to use kapag may nagtaas ng kilay sa akin!


text:
Patriots vs. Browns: Five things to watch
FOXBORO, MA. – NOVEMBER 4: New England Patriots cornerback Stephon Gilmore celebrates recovering a fumble during the fourth quarter of the game at Gillette Stadium on November 4, 2018 in Foxboro, . (Staff Photo By Nancy Lane/Boston Herald)
By Andrew Callahan | acallahan@bostonherald.com |
October 27, 2019 at 6:00 a.m.
It had been billed as one of the best regular-season matchups of the season.
The NFL's past and present versus its possible future. An upcoming challenger pitted against the reigning Super Bowl champion. An outspoken team of media darlings testing the old, boring Patriots.
Then with the Pats exceeding every expectation through Week 7 and the Browns falling flat at 2-4, some of the shine on Sunday's game is gone.
Even still, Pats-Browns should still be pretty good.
Patriots safety Devin McCourty acknowledged Cleveland's offense as the most talented the team has faced this season. Defensively, the Browns present significant matchup problems for the Pats, who continue to shuffle personnel at wide receiver and tight end. An upset still could be in the cards for Cleveland.
Here's what we'll be looking for in Sunday's Patriots/Browns matchup:
MIAMI , MA. – SEPTEMBER 15: Stephon Gilmore #24 of the New England Patriots celebrates his touchdown after a pick 6 during the fourth quarter of the NFL game against the Miami Dolphins at the Hard Rock Stadium on September 15, 2019 in Miami , Florida. (Staff Photo By Matt Stone/MediaNews Group/Boston Herald)
Stephon Gilmore vs. OBJ
There is not a single juicier individual matchup on the Patriots' schedule.
Gilmore is widely accepted as one of, if not the, best cornerbacks in the NFL. Browns wide receiver Odell Beckham Jr. has been in elite company since he entered the league in 2014. Back in 2015, when the All-Pros first met in a Bills-Giants regular-season game, they traded blows and then ensuing barbs on Instagram.
Beckham was held to five catches for 38 yards that day. A repeat performance would mean another victory for Gilmore and likely the Patriots, considering Beckham is far and away the Browns' best weapon.
The plan for Myles Garrett
Typically, Bill Belichick reserves the idea of being "unblockable" for players of All-Pro or Hall of Fame caliber. In the lead-up to the Super Bowl last February, it was Aaron Donald. In years past, it's been Lawrence Taylor.
This week, Belichick, called him "pretty much impossibly to block."
"Got great power and explosion, good get-off, very athletic, and he's blocked, but then he doesn't stay blocked. He comes free quickly and escapes and gets off blocks. Plays with a lot of power. He's certainly not a finesse player," Belichick said. "He's a very explosive, powerful guy that is also athletic enough to do very rare things."
Using the Pats' past plans for elite edge rushers as a template for this week, expect the staff to send double teams, chip blocks, cut blocks and screens at Garrett. They'll look to keep him off balance as much as they do out of their backfield. And left tackle Marshall Newhouse, who should see Garett more than anyone, will need the help.
FILE – In this Nov. 11, 2018 file photo Cleveland Browns running back Nick Chubb celebrates after scoring a 92-yard touchdown in the second half of an NFL football game against the Atlanta Falcons in Cleveland. Hue Jackson will try to help the Cincinnati Bengals beat his former Browns on Sunday, Nov. 25, 2018 providing insider information about the team he coached for three seasons. The biggest question: Can Jackson provide any tips that help Cincinnati's bad defense stop running back Nick Chubb? (AP Photo/David Richard)
Containing Nick Chubb
If there's a weakness in the Patriots defense, Browns running back Nick Chubb may be the man to exploit it.
The NFL's fourth-leading rusher is a physical back who's adept at banging between the tackles for tough yards. Through seven weeks, the Patriots rank among the worst teams in the league at defending runs up the middle, allowing more than four yards per carry. Chubb is also Cleveland's third-leading receiver, so expect quarterback Baker Mayfield to look to him as a checkdown when he extends plays.
Either way, the Browns will be counting on their lead back to extend drives. Containing him has to be a priority for the Pats defense.
Mohamed Sanu's debut
Reviewing how the Patriots introduced Josh Gordon and Antonio Brown into their offense in the last 13 months, Sanu can be expected to play roughly 20 snaps, most of them on passing plays. He'll be incorporated into a few route concepts the Pats will probably repeat and personnel groupings featuring at least three wide receivers. What he does then is up to him.
Eventually, the Patriots would like to lean on Sanu, especially in the wake of Josh Gordon's exit. That, of course, will take time. Starting Sunday, Sanu can expedite that process by earning Tom Brady's trust by securing catches on the few guaranteed targets he's sure to see Sunday.
FOXBORO MA. – OCTOBER 23: New England Patriots newly acquired receiver Mohamed Sanu was on the field during practice at Gillette Stadium on October 23, 2019 in Foxboro, MA. (Staff Photo By Nancy Lane/MediaNews Group/Boston Herald)
Who plays fullback?
Last Monday night against the Jets, four different Patriots took a crack at playing fullback.
Tight ends Ben Watson and Eric Tomlinson saw the first reps, then linebacker Elandon Roberts and offensive guard James Ferentz took turns near the goal line. None impressed, but considering all were out of position and Watson and Tomlinson signed barely a week earlier, you couldn't blame them. Heading into this week's kickoff, the fullback picture is no clearer.
Even at 6-foot-6, Tomlinson projects as the most natural fit; a strong, physical blocker with limited receiving skills and prior experience at the positions. Except before they placed Josh Gordon on injured reserve to make room for Sanu, the Pats announced they would tight end Tomlinson, a move that indicates he's currently the 53rd man on the roster. If Tomlinson fails to seize his second chance, the fullback position will either remain a revolving door or likely go to a player who's either on the street or playing elsewhere.
Ideally, the Patriots would know the answer after four quarters Sunday.
Stephon Gilmore
Andrew Callahan | Patriots Beat Reporter
Andrew Callahan covers the Patriots for the Herald through breaking news, analysis, longform stories and features. He became the Herald's Patriots beat writer in 2019 after covering a 2018 Super Bowl season for MassLive and Penn State football and basketball at CBS Sports.
acallahan@bostonherald.com
Follow Andrew Callahan @AndrewCallahan
More in New England Patriots
Patriots veteran safety Devin McCourty recovering from shoulder surgery

redpajama_set_name: RedPajamaCommonCrawl


Our growth depends to the superior products ,great talents and repeatedly strengthened technology forces for Welded Wire Mesh Fence Mesh , Welded Wire Mesh Fence Panels , Welded Wire Mesh Fence Post , flexibility and reliability which have been built during last 20 years. We focus on providing service for our clients as a key element in strengthening our long-term relationships. The continual availability of high grade products in combination with our excellent pre- and after-sales service ensures strong competitiveness in an increasingly globalized market.
"Based on domestic market and expand overseas business" is our development strategy for Welded Wire Mesh Fence Mesh , Welded Wire Mesh Fence Panels , Welded Wire Mesh Fence Post , Our main objectives are to provide our customers worldwide with good quality competitive price satisfied delivery and excellent services.


A good quote is a short piece of free form poetry. I prefer abstraction and observation over inspiration and poignancy, and mostly just value the wisdom and levity in quotes. I'll leave inspiration to be found in full blown art and concepts.


text:
Angry Birds Selects D.cn As Chinese Partner
ChinaTechNews.com Editor May 12, 2011, 12:15:04 am HKT May 11, 2011
Rovio Mobile's game Angry Birds has selected D.cn, one of the largest mobile phone game platforms in China, to provide free-to-download services in various editions.
Xiao Yongquan, chief executive officer of D.cn, told local media that D.cn has been focusing on the mobile gaming field and it provides comprehensive mobile gaming services to users. While implementing extensive cooperation with quality Chinese mobile game developers, it has been seeking opportunities to introduce more game products from abroad.
Developed by Rovio Mobile, Angry Birds is one of the most popular games in the world. It started selling in Apple's App store in December 2009, and became the most popular application in Finland overnight.
Rovio Mobile previously expressed its interest in the Chinese market and believed China is a large potential market with its nearly 900 million mobile phone users. The cooperation between Angry Birds and D.cn will mark the prologue of Rovio Mobile's fast expansion in the Chinese mobile phone game market.
Commenting on the development in the Chinese market, Peter Vesterbacka, an executive from Rovio Mobile, told local media that the company hopes to gain 100 million users in China in 2011; and it wants to soon become a leading entertainment brand in China.
Angry Birdsmobilemobile gamemobile gamingWirelesswireless game
Giant Sets Up Mobile Game Publishing Company
NetEase Invests USD25 Million In Finnish Gaming Start-up
Kunlun.com Announces CNY1 Billion Mobile Game Publishing Plans
Baidu Integrates Mobile Game Businesses


text:
Cemalettin Aydin
Ibrahim Kara
Yasin Ay
Bekir Inan
Halil Basel
Mehmet Yanartas
Rahmi Zeybek
Home > Vol 29, No 1 (2013) > Aydin
Ischaemic mitral regurgitation: The effects of ring annuloplasty and suture annuloplasty repair techniques on left ventricular re-remodeling
Cemalettin Aydin, Ibrahim Kara, Yasin Ay, Bekir Inan, Halil Basel, Mehmet Yanartas, Rahmi Zeybek
Objective: To examine the mid-term results of patients on whom a coronary revascularization as well as a mitral ring and suture annuloplasty have been performed due to coronary artery disease (CAD) and ischaemic mitral regurgitation (IMR).
Methodology: Totally 73 patients on whom a revascularization and a mitral valve repair due to CAD and IMR had been performed in our clinic between 2000-2008 were included in the study. Patients were divided into two groups one of which included 38 patients (52.05%) on whom a coronary artery bypass graft (CABG) and a ring annuloplasty on the mitral valve had been performed (Group 1) and the other one 35 patients (47.95%) on whom only suture annuloplasty as well as a CABG had been performed (Group 2). The study was planned retrospectively and study data have been obtained by screening the hospital registries retrospectively. In the mid-term, patients were invited for a check and their intragroup and intergroup echocardiographic parameters and functional capacities were assessed statistically.
Results: In pre-operational and post-operational intragroup assessment in terms of echocardiographic findings; although LVEDD, LVESD, EDV, PAP and the degree of recurrent MR have been decreased in both groups, the decrease in LVESD and PAP and the low degree of recurrent MR were statistically significant in Group 1 patients (p=0.047, p=0.023, p=0.01, respectively). When the mid-term intergroup echocardiograpic findings were assessed; PAP and recurrent MR have been determined statistically lower in Group 1 patients (p=0.005, p=0.08, respectively). The length of intensive care unit stay, length of hospitalization and length of detachment from respiratory support were statistically significantly longer in ring annuloplasty performed group (p=0.012, p=0.033, p=0.029, respectively).
Conclusions: In moderate to severe IMR patients, a positive contribution can be provided to ventricular remodeling by a ring annuloplasty through a significant decrease in left ventricular diameter and a low recurrent MR and PAP.
doi: http://dx.doi.org/10.12669/pjms.291.2760
How to cite this:Aydin C, Kara I, Ay Y, Inan B, Basel H, Yanartas M, et al. Ischaemic mitral regurgitation: The effects of ring annuloplasty and suture annuloplasty repair techniques on left ventricular re-remodeling. Pak J Med Sci 2013;29(1):31-36. doi: http://dx.doi.org/10.12669/pjms.291.2760
Jual Obat Bius Wanita Ampuh Sekali Minum Langsung Pingsan


text:
'Lorena' is Another Eye-Opening Return to a Tabloid Sensation
By Jason Bailey
The first two images of Lorena, Joshua Rofé's new documentary series (debuting tomorrow on Amazon Prime) are tight shots of objects outside a home. The first is an American flag; the second is a satellite television dish. They are, in essence, what the movie is about, and if the placement isn't exactly subtle, well, they're telling the story of the woman who cut off her husband's penis. Subtlety doesn't really enter into it.
Her name was Lorena Bobbitt — these days, she goes by her maiden name of Gallo — and the first episode of Lorena, "The Night Of," begins with what we (sort of) already know: how, on the night of June 23, 1993, the manicurist used a kitchen knife to remove her husband's member, and then fled the scene, tossing it in a nearby field. Rofé talks to just about everyone involved — cops, doctors, nurses — and in the process, indulges in some of the same giggling and winking we all partook of, when this story broke. ("It hadn't been found, it hadn't been heard from, it was lost in action.") Even she laughs about it herself. A little.
But this was not a funny story, and not only because of the graphic photos (all included here, of course). It was because of what prompted the crime: years of abuse and marital rape, culminating in an evening when Lorena had quite simply had enough, and took an action severe enough to ensure that husband John Wayne Bobbitt would never touch her again.
(Amazon)
In other words, Lorena is all of a piece with several recent works of non-fiction and docudrama — I, Tonya, the Clinton season of Slow Burn, The People vs. O.J. Simpson , and its most direct influence, the Oscar-winning O.J.: Made in America — that revisit the sleaziest, tabloid-friendliest stories of the 1990s, and not only reframe how we look and think about them, but indict the callous way we, as a culture, treated the women at their centers.
Lorena remembers that this story was the continuation of a conversation that was in progress throughout the early 1990s, from the testimony of Anita Hill to the trail of William Kennedy Smith to the horrifying allegations at Tailhook — front page stories that underlined, in a way quite rare in open conversation, the day-to-day dangers of simple existing in the world as a woman. So, contrary to its presentation, this was not an A-leads-to-B-leads-to-C cause/effect type of story; this was a tale filled with detours and backtracks, which Rofé and his editors elegantly replicated in the film's ingenious structure.
To that end, she goes back and tells her full story in the second installment, "A Woman in Trouble," which covers the period around their first trial — in which John was charged, and acquitted, of sexual assault — and the story's domination of what is accurately dubbed "an evolving media landscape," a swirling morass of CNN, tabloid press, and COURT TV. In delicately detailing how this story was told and framed, we're reminded of the "Hot-blooded Latina" caricature that seemed so easy, and the cheap jokes that seemed so pervasive. And many of them were told by Mr. Bobbitt himself, who took the opportunity to transform himself into some kind of sad-sack pseudo-celebrity — famous not for any particular talent or charisma, but simply for being famous — most often via his appearances with Howard Stern. And, side note, I'd recommend anyone willfully participating in the latter-day lionization of Stern do their best to defend the radio clip in which he announces, "I didn't buy this whole thing that he was raping her. She's not even that good-looking." I'd also like Stern to defend it, but who are we kidding.
Stern's grinning, elbow-in-the-ribs enabling of Wayne's notoriety and faux-victimhood are particularly hard to swallow when viewing Lorena's testimony, which (and here is an advantage of a docu-series running four hours) is presented here at great length, so powerful and so persuasive. It is, make no mistake, hard to watch, detailed descriptions of physical and sexual assault, and Lorena stays with her through this ordeal, as she searches for words and strength. The title of the third episode, "An Irresistible Impulse," comes from the legal terminology embedded in her successful defense (a temporary insanity plea, basically); the fourth, "The Cycle of Abuse," comes from the notion that this behavior comes from somewhere, and it's worth trying to figure out where.
As with the closing episode of O.J., part four of Lorena spends a fair amount of time on its male antagonist's cringe-inducing attempts to remain in the spotlight; in the case of John Wayne Bobbitt, this came in the form of job trouble, money trouble, more arrests, and porn. But to his credit, Rofé lets both of them have their say, though in the case of J.W., it's very much a "give him enough rope to hang himself" situation; by the end of the series, Lorena has become, among other things, the portrait of a sociopath, a man who's told so many lies for so long, it almost seems like he believes them himself. (He is, in the series' least surprising revelation, a Trump guy.)
Lorena is an expertly crafted piece of work — this is a messy, complicated case, and Rofé and his team sift through a lot of information. If he leans a bit too hard on some of the tropes of the form (there are, as with most recent non-fiction films, too damn many drone shots), he also deploys them well; the reenactments are minimal and tasteful, and crisply intercut with the corresponding courtroom footage. Throughout the film, in fact, the juxtapositions are striking, and never more so than at the end, when Lorena reads aloud from the love letters John still sends her, and Lorena cuts away to the old but still affecting photos of the damage he did. And then she puts the letters down, scarcely believing their contents herself. "I cut his penis off!" she shrugs, not unreasonably. "Just leave me alone!"
Lorena debuts on Amazon Prime this Friday.


ICICI Securities, a subsidiary of private sector lender ICICI Bank, has received markets regulator Securities and Exchange Board of India's (SEBI) approval to raise an estimated Rs 3,000 - Rs 4,000 crore through an Initial Public Offering (IPO). Last year in December, the company had filed its draft papers with SEBI and received observations from the regulator on February 2.
The public issue comprises sale of 64,428,280 equity shares, amounting to 20% stake, by ICICI Bank. The offer includes a reservation of up to 32.21 lakh shares for individual as well as Hindu Undivided Family (HUF) shareholders of ICICI Bank.
DSP Merrill Lynch, IIFL Holdings, SBI Capital Markets, Citigroup Global Markets India, Edelweiss Financial Services and CLSA India are book running lead managers to the issue.
ICICI Securities provides institutional and retail broking, merchant banking, and advisory services to corporates, financial institutions, high net-worth individuals, and retail investors in India.


Paul planted. Apollos watered. God gave the increase.
The Sunday School's Vision Statement is to make the fullness of God's word a reality in every believer's life. Our Mission is to build a biblical foundation in the lives of individuals that will transform families, friends, and the community for the Kingdom of God.Our Sunday school teachers meet bi-monthly to make sure that our Vision and Mission Statements are fulfilled.


text:
import { combineReducers } from 'redux'

import config from './config'
import account from './account'
import designs from './designs'
import preview from './preview'

export default combineReducers({
    config,
    account,
    designs,
    preview
})

redpajama_set_name: RedPajamaGithub


text:
Lewis Hamilton talks about his SECOND £32m luxury Manhattan penthouse
LEWIS Hamilton is well known for his love of the high life and the F1 ace lived up to his image after splashing out on a second £32 million Manhattan penthouse. The Formula One ace, 34, picked a four-bed pad in a complex that is popular with celebrities, and is only a block from another penthouse he bought in 2020.
READ ALSO Ex-F1 Driver Warns Teams of Lewis Hamilton 'Regret' Amidst Retirement Rumors.
The apartment is at 70 Vestry Street, a limestone building designed by Robert A.M. Stern architects, according to The Wall Street Journal. Hamilton's new four bedroom property looks out onto the Hudson River and is complete with a courtyard, an 82ft long swimming pool, a squash court and a library.
The Wall Street Journal reports that he has another pad round the corner at 443 Greenwich Street where other star names including Jennifer Lawrence and Mike Myers have lived. Hamilton won his fifth world title last season, putting him in an elite group of three drivers who have achieved the landmark.
READ ALSO Former F1 Driver Reveals Biggest Problem With Replacing Masi.
Michael Schumacher is out in front with seven and Juan Manuel Fangio also claimed five titles. While a champion on the track he is also a star turn off it and is always keen to brace the limelight. Hamilton is the most marketable figure currently in Formula One with endorsements which include with Mercedes-Benz, Tommy Hilfiger, Monster Energy, Puma, IWC and Sony.
READ ALSO Ex-F1 Champion Brutally Shuts Down a Lewis Hamilton Fan on Twitter
Related Topics:Lewis HamiltonMercedes
LOVE AT FIRST SIGHT VANESSA SHARE: SEE THE MOMENT WHEN KOBE BRYANT FIRST SAW HIS WIFE OF ALMOST 20-YEARS VANESSA
Verstappen expects to 'lose out' at Turkish Grand Prix start
"Already Texted Hamilton": FIA President Personally Involved in Abu Dhabi Investigation.


text:
Clavatorella es un género de foraminífero planctónico considerado un sinónimo posterior de Protentella de la familia Catapsydracidae, de la superfamilia Globorotalioidea, del suborden Globigerinina y del orden Globigerinida. Su especie tipo era Hastigerinella bermudezi. Su rango cronoestratigráfico abarcaba desde el Langhiense (Mioceno medio) hasta el Zancliense (Plioceno inferior).

Descripción
Clavatorella incluía especies con conchas trocoespiraladas, de forma estrellada; sus cámaras eran inicialmente globulares y finalmente alargadas radialmente o claviformes; sus suturas intercamerales eran incididas; su contorno ecuatorial era fuertemente lobulado; su periferia era redondeada; su ombligo era amplio y somero; su abertura principal era interiomarginal, umbilical-extraumbilical, con forma de ranura asimétrica y protegida por un pórtico; los pórticos de la aberturas de las cámaras precedentes se unen en el área umbilical; presentaban pared calcítica hialina, perforada con poros en copa y superficie reticulada y espinosa.

Discusión
Clasificaciones posteriores incluirían Clavatorella en la familia Globorotaliidae. Clavatorella fue propuesto como un subgénero de Protentella, es decir, Protentella (Clavatorella).

Paleoecología
Clavatorella incluía foraminíferos con un modo de vida planctónico, de distribución latitudinal tropical a templada, preferentemente tropical, y habitantes pelágicos de aguas intermedias e profundas (medio mesopelágico a batipelágico superior).

Clasificación
Clavatorella incluía a las siguientes especies:

 Clavatorella bermudezi †
 Clavatorella nicobarensis †, considerado como Protentella nicobarensis †
 Clavatorella oveyt †
 Clavatorella paleocenica †
 Clavatorella prolata †
 Clavatorella salumensis †
 Clavatorella sturaniii †

Referencias

 Géneros de foraminíferos planctónicos


text:
(4375) Kiyomori es un asteroide perteneciente al cinturón de asteroides, descubierto el 28 de febrero de 1987 por Tsuneo Niijima y el astrónomo Takeshi Urata desde el Ojima Observatory, Ojima, Japón.

Designación y nombre
Designado provisionalmente como 1987 DQ. Fue nombrado Kiyomori En honor al samurai Taira no Kiyomori

Características orbitales
Kiyomori está situado a una distancia media del Sol de 2,293 ua, pudiendo alejarse hasta 2,532 ua y acercarse hasta 2,054 ua. Su excentricidad es 0,104 y la inclinación orbital 5,863 grados. Emplea 1268 días en completar una órbita alrededor del Sol.

Características físicas
La magnitud absoluta de Kiyomori es 13,1.

Véase también
 Lista de asteroides del (4301) al (4400)
 Cuerpo menor del sistema solar

Referencias

Asteroides del cinturón principal
Objetos astronómicos descubiertos por Tsuneo Niijima
Objetos astronómicos descubiertos por Takeshi Urata
Objetos astronómicos descubiertos desde el Ojima Observatory
Objetos astronómicos descubiertos en 1987
Wikiproyecto:Asteroides/Artículos de asteroides


At MetaBroadcast, we're always trying to improve our workflow, and one of the ways we do this is by constantly reviewing our tools to ensure they are making us more productive. Every quarter, we all get together somewhere away from the office where we discuss the progress we've made and how we can improve in future (we call these "Away Days"). The topics to discuss are different at each Away Day, and this time I was on a team discussing how we can improve our build process.
Internally, we use Skype for communicating asynchronously with each other. We use Github's Hubot automator in order to build projects directly from a Skype room. We generally have a room in Skype per project and have commands to deploy projects from a branch of one of our Git repositories, to either staging or production environments. While this is certainly great for making quick deploys, we could probably make the commands a little more flexible. For example, why shouldn't Hubot know what room it's in and then assume that's the project we'd want to deploy? This seems like a small common sense change to allow us to be more productive. Also, it can be somewhat confusing trying to remember the different commands without flooding the chat room with hubot help. We'd like there to be more ways to give the same command to Hubot, so we can guess commands and, most of the time, be right!
Just recently, we've been growing dissatisfied with Jenkins, which we use as our continuous integration server. It's a pain to configure, a bit on the slow side and the UI is somewhat frustrating to use. We've made a commitment to start looking at alternatives to Jenkins, that are able to build Atlas, Voila and Engage quickly and with minimal developer frustration.
As time goes on, we've been deploying more Node.js applications to our servers, and we plan to deploy other types of web applications in the future that don't fit our current deploy process for Atlas. In the interest of keeping up with the current trends as well as finding the best tool to handle these kind of deploys, we're looking into how Docker can improve this process for us.
The aim of Docker is to to package applications into a container, deploy it and run it on a server. Docker packages extend the LXC container format and create namespaced and isolated virtualisation on a single Linux kernel. It's hardware and language agnostic – giving us the ability to be able to quickly deploy an app written in any language on any hardware. We're excited to see whether this is a good fit for the kinds of applications we make at MetaBroadcast, and possibly for Atlas in future, too.
Have you been reviewing your build process recently? We'd love to hear your suggestions on how we can continue to improve ours. Feel free to leave us a comment below or send us a tweet!


text:
US sets new Cuba sanctions as Biden meets Cuban-Americans
Washington, Jul 31 (AP): The Biden administration announced new sanctions on Friday against Cuba's national revolutionary police and its top two officials as the US looks to increase pressure on the communist government following this month's protests on the island.
The Police Nacional Revolcionaria and the agency's director and deputy director, Oscar Callejas Valcarce and Eddie Sierra Arias, were targeted in the latest sanctions announced by the Treasury Department's Office of Foreign Assets Control. The police are part of Cuba's interior ministry, which was already the subject of a blanket designation by the Trump administration back in January.
"We hear the cries of freedom coming from the island. The United States is taking concerted action to bolster the cause of the Cuban people," President Joe Biden said at the start of a White House meeting with Cuban Americans not long after Treasury announced the sanctions.
The administration says it is considering a wide range of additional options in response to the protests, including providing internet access to Cubans, and has created a working group to review US remittance policy to ensure that more of the money that Cuban Americans send home makes it directly into the hands of their families without the government taking a cut. Biden added that more sanctions were in the offing.
The White House meeting comes almost three weeks after unusual July 11 protests in which thousands of Cubans took to the streets in Havana and other cities to protest shortages, power outages and government policies. They were the first such protests since the 1990s.
The Cuban regime deployed the PNR to attack protesters, the Treasury Department said in a statement. The police were photographed confronting and arresting protesters in Havana, including members of the Movement of July 11 Mothers, a group founded to organize families of the imprisoned and disappeared, according to Treasury.
In Camagüey, a Catholic priest was beaten and arrested by the PNR while he was defending young protesters, according to Treasury. PNR officers also beat a group of peaceful demonstrators, including several minors, and there have also been documented instances in which the PNR used clubs to break up peaceful protests across Cuba, Treasury said.
"The Treasury Department will continue to designate and call out by name those who facilitate the Cuban regime's involvement in serious human rights abuse," said Andrea Gacki, director of the Office of Foreign Assets Control.
"Today's action serves to further hold accountable those responsible for suppressing the Cuban people's calls for freedom and respect for human rights." Among the Cuban American activists meeting with Biden was Yotuel Romero, one of the authors of the song "Patria y vida!" which has become a kind of anthem for the protests, said an official.
Others present included L Felice Gorordo, CEO of the company eMerge Americas; Ana Sofía Peláez, founder of the Miami Freedom Project, and Miami's former mayor, Manny Díaz, and Sen. Robert Menendez, a New Jersey Democrat and chairman of the Senate Foreign Relations Committee.
White House officials said Biden would discuss the new sanctions as well as ways to potentially establish internet access for the Cuban people.
Internet access is a sensitive issue in Cuba. In the days before the recent protests, there were calls on social media for anti-government demonstrations. Cuba's government said anti-Castro groups in the United States have used social media, particularly Twitter, to campaign against it and blamed Twitter for doing nothing to stop it.
Internet service was cut off at one point during the July 11 protest, though Cuban authorities have not explicitly acknowledged that they did it.
Some US leaders, including Florida Gov. Ron DeSantis, have said the White House should do something to maintain internet service in Cuba, including using balloons as Wi-Fi access points for the population.
The Biden administration is also considering proposals put forward by US advocates of trade with Cuba that would restore ways for Cuban-Americans to send money to relatives on the island.
Biden and others have rejected the outright restoration of remittances because of a percentage fee of the transaction paid to the government. But under one proposal being considered, the transfer agents would waive that fee until the end of the year, according to proponents.
The proposal would have to be cleared by the Cuban government, however, and it is not at all clear it would agree.
Last week, the US government announced sanctions against the minister of the Cuban armed forces, Álvaro López Miera, and the Special Brigade of the Ministry of the Interior — known as the "black berets" — for having participated in the arrest of protesters.
International organisations have harshly criticized the Cuban government, which has said that while people affected by the country's crisis participated in the protests there were also "criminals" who took advantage of the situation to create disturbances. At times, the protests turned into vandalism with looting, robbery and confrontations with the police.
Government sympathizers also took to the streets to defend the authorities and the revolution.
So far it is unclear how many people were detained, although the judicial authorities have said there have been 19 trials involving 59 people. (AP) CPS
(This story is published as part of the auto-generated syndicate wire feed. No editing has been done in the headline or the body by ABP Live.)
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text:
A Preliminary Appraisal --
What the China Trip Signifies
By DEIRDRE GRISWOLD
It has been apparent for several years now, and was confirmed by the publication of the Pentagon Papers that the great victories of the Vietnamese and Indochinese peoples marked the end of an era for U.S. imperialism. As Sam Marcy, Chairman of Workers World Party wrote in this newspaper last July: "That phase of American history which . . . saw aggressive American finance capital reach the pinnacle of its power on the world arena has forever vanished."
Nixon's trip to China reflects this new reality, and was an attempt to retrieve in the diplomatic and political arena what could not be won on the battlefield with the costliest and most modern weaponry. But the motives of the U.S. ruling class in underwriting the Nixon trip should be clear to all but the most brainwashed. The question troubling revolutionaries and those who side with the oppressed of all nations is: Why did China do it?
There are actually two separate questions to be considered. The first concerns China's natural desire to normalize state relations with the United States, which involves diplomatic recognition, an end to the embargo on trade, a broadening of travel, etc. Despite the absolutely irreconcilable character of the class antagonisms between capitalism and socialism, such normalization can be possible without sacrificing revolutionary internationalism, without yielding any ground in the struggle to raise the consciousness of the workers and oppressed. In the Soviet Union at the time of Lenin (when all other nations were either capitalist or colonized by them), Soviet diplomacy adhered to this principle.
In the joint communique issued by the U.S. and the People's Republic of China at the end of the discussions, a major breakthrough in the diplomatic recognition of China by the U.S. was announced. Taiwan, the island fortress where U.S. men and arms have kept alive the corrupt and repressive regime of Chiang Kai-Shek, is no longer called by Washington the "legitimate" government of all China, and U.S. troops are to be removed as the first step toward the reunification of Taiwan with mainland China without outside Interference. This is certainly a significant victory for People's China, one which brings the liberation of Taiwan that much closer. We hope that the People's Republic has also derived other benefits from these talks.
The crucial question, however, in this epoch of the transition on a world scale from capitalism to socialism, is what effect will the new relationship between China and the U.S. have on the national liberation movements and on proletarian revolutionaries throughout the world? At this writing, it is impossible to foresee what all the long-range effects will be, and Workers World will have more to say on this later. However, based on the spirit of the visit that has just taken place, one conclusion is irresistible: we are compelled to recognize that the principled foreign policy of revolutionary internationalism for which the People's Republic fought so hard in the international communist movement, and which was so reviled by the Soviet revisionists, has been revoked. The present relations with U.S. imperialism are being carried out in the revisionist spirit of peaceful coexistence, or class conciliation, instead of class struggle, which China so correctly denounced in the past.
This summit meeting was held in the "spirit of Camp David, when Khrushchev came to meet Eisenhower and called him a man of "peace." The Chinese leadership, while it is not guilty of such deceptive pronouncements, has allowed Nixon to appear in such a light without contradiction. The very fact that Nixon was allowed to use the territory of a socialist country to launch a gaudy, extravagant election campaign makes a mockery of what sounds good and revolutionary in the Chinese statement. The very fact that the Chinese leadership can toast the imperialist chief of state while his troops are still engaged in murder and plunder just on the other side of the border sows demoralization and pessimism in the hearts of dedicated fighters who have been willing to give their very lives in the struggle for a new world. Much, much more has been involved in this historic week than a movement to normalize state relations between China and the U.S. Such a development does not require face-to-face meetings between the two heads of state. Kissinger, or Rogers, or a dozen lesser officials could have made the necessary contacts for such an arrangement. The display, the pomp, the banquets and toasting, the 40 hours of private discussions between Richard Nixon and Chou En-Lai, all these features of the visit lead everyone to suppose, despite ail the official denials, that a secret agreement or at least the initial stages of such an agreement, much broader than the joint communique on Taiwan, was the result of the trip. One of the first moves of the new Soviet state in 1917 was to make public all the secret agreements made by the Czar. "Open diplomacy" was a principle of Leninism that received an immediate response from the masses all over the world, who have been the object of history for so many centuries. Thus principle was long ago abandoned by the revisionist Soviet leadership.
It is because any socialist country, and especially one with a great revolutionary tradition, carries such great moral authority with the progressive masses of the world that its every act must be judged first and foremost by these criteria does it help raise the class consciousness of the masses: does it inspire them to struggle against the class enemy -- in this case, the worst enemy of humanity as the Chinese themselves have so often called U.S. imperialism? Judged from this viewpoint, it is only too clear that the abrupt turn in China's attitude toward the U.S. can do nothing but confuse the masses and sap the energies of the vanguard.
(There is, of course, a plus in the fact that people in this country are finally getting a glimpse at the stunning accomplishments of the Chinese Revolution. Many of the lies about China were demolished by the photographic evidence of healthy, energetic people living in a modern society.)
DIFFER WITH POLICY BUT CONTINUE TO SUPPORT SOCIALIST STATE
Workers World's analysis of the revisionist turn in China's foreign policy should not be confused with the hysterical accusations being heaped on the People's Republic by those parties that do not support her socialist economic foundations nor have any respect for the great revolutionary accomplishments of her leaders. We have been unswerving supporters of China since the establishment of this great socialist state. We welcomed China's revolutionary criticism of the Soviet Union's revisionist role, and the pages of this newspaper have reprinted many of the most significant Chinese statements attacking class conciliation and capitulation to imperialism in the international communist movement.
We exposed India's attempts at aggression (encouraged by U.S. imperialism) in the border dispute, at a time when the Indian Communist Party (pro-Moscow) entirely supported the Nehru government. Workers World saw in the Cultural Revolution a mighty attempt to disintegrate a movement that would restore class privilege, and eventually capitalist rule.
Furthermore, our support of the People's Republic of China as a socialist state, as a society where the privileged ruling classes have been expropriated and their mechanism of rule shattered, remains unshakable despite our disagreement with the policies of the leadership.
But this new page in world relationships brought about under the tremendous pressure of imperialism, still so vastly wealthy even though in social eclipse, combined with the hostility of the Soviet revisionists -- demands more than ever that serious revolutionaries sharpen the tools of Marxism-Leninism, perceive the validity of the class struggle, and continue to prepare themselves and the masses for the social cataclysms that will inevitably accompany the breakup of this decaying system.
WWP LEADER FORESAW
POSSIBLE SINO-U.S. AGREEMENT
At the 1966 Labor Day Conference of Workers World Party, Chairman Sam Marcy discussed the then-theoretical possibility that the Sino-Soviet split might drive China into an agreement with U.S. imperialism: "If the ideological struggle between the Chinese party and the Soviet revisionists deepens and becomes a struggle between states, then it is possible that People's China may make a pact with the U.S. against the USSR. This would be a modern version of the Stalin-Hitler Pact."
Comrade Marcy explained that such a development would not change the attitude of the WWP toward People's China itself. Workers World would defend China against imperialism even though we disagreed with the policy, just as we defended the Soviet Union while attacking the way in which the Stalin-Hitler Pact was carried out.
"What we opposed in Stalin at that time," said Comrade Marcy, "was not the principle of his right to enter into an agreement with an imperialist nation. What we opposed was the way it was done -- the secrecy, the shock to the proletarian forces, his painting up of the enforced agreement as a great thing and his softening of his previous position against Hitler as a result.
"Similarly, after Hitler broke the pact and turned has guns on the Soviet Union, we opposed Stalin's painting up the imperialist democracies. We opposed his demoralizing the world proletariat with the idea that the democratic imperialists were fundamentally superior to the fascist imperialists, although of course we defended the Soviet Union against the fascists. Stalin's position seriously weakened the conscious forces of world revolution and in the long run eroded the revolutionary role of the Soviet Union on the world arena."


text:
Journal Home About Issues in Progress Current Issue All Issues Feature Issues
•https://doi.org/10.1364/OE.415494
Delivery of CW laser power up to 300 watts at 1080 nm by an uncooled low-loss anti-resonant hollow-core fiber
Xinyue Zhu, Dakun Wu, Yazhou Wang, Fei Yu, Qiurui Li, Yunfeng Qi, Jonathan Knight, Shufen Chen, and Lili Hu
Xinyue Zhu,1,2 Dakun Wu,3,7 Yazhou Wang,2,4 Fei Yu,2,3,8 Qiurui Li,5 Yunfeng Qi,5 Jonathan Knight,6 Shufen Chen,1 and Lili Hu2,3
1School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
2Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
3Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China
4Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
5Shanghai Key Laboratory of All Solid-State Laser and Applied Techniques, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
6Centre for Photonics and Photonic Materials, Department of Physics, University of Bath, Claverton Down, Bath, BA2 7AY, United Kingdom
7wudakun@ucas.ac.cn
8yufei@siom.ac.cn
Dakun Wu https://orcid.org/0000-0002-4962-4549
Fei Yu https://orcid.org/0000-0002-1831-859X
Jonathan Knight https://orcid.org/0000-0002-0802-8804
Lili Hu https://orcid.org/0000-0003-2342-5688
X Zhu
D Wu
Y Wang
F Yu
Q Li
Y Qi
J Knight
S Chen
L Hu
Xinyue Zhu, Dakun Wu, Yazhou Wang, Fei Yu, Qiurui Li, Yunfeng Qi, Jonathan Knight, Shufen Chen, and Lili Hu, "Delivery of CW laser power up to 300 watts at 1080 nm by an uncooled low-loss anti-resonant hollow-core fiber," Opt. Express 29, 1492-1501 (2021)
Single-mode solarization-free hollow-core fiber for ultraviolet pulse delivery
Fei Yu, et al.
Opt. Express 26(8) 10879-10887 (2018)
Understanding the material loss of anti-resonant hollow-core fibers
Dakun Wu, et al.
Hollow-core fibers for high power pulse delivery
Mattia Michieletto, et al.
Opt. Express 24(7) 7103-7119 (2016)
Table of Contents Category
High power lasers
Hollow core fibers
Laser beams
Nonlinear effects
Original Manuscript: November 20, 2020
Revised Manuscript: December 17, 2020
Manuscript Accepted: December 23, 2020
Article Outline
AR-HCF for high-power laser delivery
Experiment of high-power laser delivery by AR-HCF
Equations (3)
In this paper, we report the use of a 3-meter low-loss anti-resonant hollow-core fiber (AR-HCF) to deliver up to 300 W continuous-wave laser power at 1080 nm wavelength from a commercial fiber laser source. A near-diffraction-limited beam is measured at the output of the AR-HCF and no damage to the uncooled AR-HCF is observed for several hours of laser delivery operation. The limit of AR-HCF coupling efficiency and laser-induced thermal effects that were observed in our experiment are also discussed.
© 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Demand for flexible laser power delivery using optical fiber has been growing with the rapid development of high-power laser sources which could find extensive applications in micro-machining, laser surgery, defense technology and other applications [1–3]. The power handling ability of conventional optical fiber is determined by its laser power damage threshold, nonlinear optical effects and thermal induced modal degradation, all of which are ultimately constrained by the glass core. Hollow-core fibers (HCFs) confine the light in the hole and provide a nearly free-space propagation environment with a much higher damage threshold, lower optical nonlinearity, and lower waveguide dispersion. These unique advantages give HCFs the potential to outperform the solid-core fiber [4], particularly in high-power laser delivery.
Thanks to the concept of microstructured design, HCFs can have attenuation as low as tens of dB/km or less, and therefore HCF-based high-power laser delivery is becoming practical. Photonic-bandgap hollow-core fiber (PBG-HCF) (the first kind of low-loss HCF) has been used to deliver laser pulses by taking advantage of its low dispersion and low optical nonlinearity [5–7]. In 2016, a PBG-HCF successfully delivered 76 W average power picosecond laser pulses at 1032 nm, with 1.9 µJ pulse energy of 22 ps pulse [8]. PBG-HCFs were also used to transmit continuous wave (CW) laser [9,10] and up to 100 W CW laser power delivery was successfully demonstrated [11].
Kagome-HCF, a different type of microstructured HCF, has been widely used in ultrafast pulse compression, and high power/high field laser transmission [12–17]. In 2014, pulsed laser of 18 µJ and 740 fs, with 118 W average power was coupled into a Kagome-HCF filled with 13 bar of argon for spectral broadening and compression [18]. For few-cycle laser pulse transmission, undistorted 10 fs and 6.6 nJ pulses were launched into a 1 m long Kagome HCFs with 80% transmission efficiency reported [19]. S. Hädrich et al. [20] delivered few-cycle laser with an average power up to 900 W, using a Kagome HCF that was cooled in the experiment and the laser delivery operation lasted for about 20 minutes in experiment.
Inspired by the concept of negative-curvature core boundary [21], the negative-curvature anti-resonant hollow-core fiber (AR-HCF) was first proposed in 2011 [22]. AR-HCFs are known for their simplified cladding and the large hollow core, which can efficiently confine the light with low loss [23–25]. In AR-HCF, light is guided in the central hollow core by taking advantage of the ultrathin negative-curvature core wall ranging from hundreds of nanometers to a few micrometers generally [26–28] which works in a way analogous to a Fabry-Perot resonator. Additionally, the high order modes (HOMs) in the core would be effectively filtered by coupling with cladding modes when the phase matching condition is satisfied so that AR-HCF could possibly achieve a quasi-single-mode guidance [29]. Besides, comparing with PBG-HCF and Kagome-HCF, AR-HCFs have the largest core diameter for the same spectral transmission window which is key for leakage loss reduction and meanwhile brings down the power fraction of mode field distributed in the host material of cladding [30,31], helping to boost the laser damage threshold significantly. It is noted that the flexibility of AR-HCF would be hindered at some extent by its bending sensitivity and a systematic experimental characterization is found in [32]. So far, pulsed laser delivery using AR-HCF has been extensively studied, most at visible and near-infrared wavelengths [33–39]. In the visible spectral region, AR-HCF was used to deliver a high energy pulsed laser with around 0.57 mJ (10.4 kW peak power) and 30 µJ (5 MW peak power) pulse energies at 532 nm and 515 nm respectively [40]. As for the near-infrared, an average laser power of over 70 W at 1032 nm with 22 ps pulse duration and 10 MHz repetition rate was transmitted in AR-HCF [41]. Meanwhile, ultraviolet (UV) pulse delivery by AR-HCF has also been demonstrated [42,43]. Yu et al. reported solarization-free UV pulse transmission by AR-HCF, delivering 17 ns laser pulses at 266 nm at 30 kHz repetition rate [43].
In this paper, we successfully demonstrate 300 W CW laser power delivery over 3 m AR-HCF fiber length at 1080 nm. No fiber damage is observed for 400 W incident power, limited by the maximum output of our fiber laser source. We experimentally characterize the temporal stability of laser transmission in AR-HCF, beam quality and numerical aperture at the AR-HCF output as function of incident power. Optimization of free-space laser beam coupling with AR-HCF is modelled and discussed.
2. AR-HCF for high-power laser delivery
The AR-HCF used in this paper is fabricated by stack-and-draw technique, starting with Heraeus F300 fused silica tubes. It consists of a ring of seven capillaries forming the cladding (inset of Fig. 1), with a core diameter of about 35 µm and an average capillary inner diameter of 17 µm. The 7-capillary cladding design of AR-HCF is preferred in the fabrication for optimized balance between the single-mode guidance [44] and minimization of cladding gaps for lower leakage loss [45]. The thickness of negative-curvature core wall is about 355 nm on average, indicating the first and second resonance wavelengths around 750 nm and 384 nm wavelengths, respectively. The attenuation of the AR-HCF measured by the cut-back method is shown in Fig. 1 and 0.05 dB/m is obtained at 1080 nm wavelength.
Fig. 1. The measured attenuation of the AR-HCF by a cut-back from 132 m to 12 m. Inset: SEM picture of AR-HCF. The core diameter is about 35 µm.
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3. Experiment of high-power laser delivery by AR-HCF
3.1 Experimental setup
Figure 2 shows our CW laser delivery experiment setup. 3 meters AR-HCF, which is relatively suitable for high power delivery, was loosely rewound on a steel plate in a circle with a radius of about 50 cm to be confident that we would not introduce resonant bend loss [32]. Such large loop diameter is preferred to avoid the possible burning of fiber coating by bend induced laser power leakage which would severely damage AR-HCF. It is noted that the acrylic coating was not stripped off from AR-HCF except at the two fiber ends. The fiber was not cooled during the experiment.
Fig. 2. Schematic of laser delivery setup: L1, L2, L3, L4 are coated aspherical lens with f1 = 100 mm, f2 = 150 mm, f3 = 120 mm, f4 = 100 mm; M1, M2, M3, M4,M5 are dielectric mirrors which reflect > 99.5%; M6 is a back polished mirror used as a sampler (transmittance <<1%); Another sampler (99:1) is used to monitor the power of laser source and calibrate the incident power at the input end of the AR-HCF in real time. PM1, PM2 are power meters. AR-HCF is mounted on a silica V groove loaded on a XYZ stages. No cooling method is applied.
An industrial CW fiber laser (Feibo YDFL-500-QCW) used as the source provides a maximum power up to 400 W at 1080 nm. M2 measurement of laser output is shown in Fig. 4. The laser beam leaving the end cap is 5 mm in diameter according to the specification. A 4-f lens system is designed and used to scale the laser beam and couple with AR-HCF.
In the experiment, about 15 cm coating was stripped off of the AR-HCF ends to avoid burning damage caused by the uncoupled laser power. The bare fiber end was mounted on a silica V-groove on a XYZ stage (Thorlabs MAX313D). A sampler is used to monitor the incident power and calibrate the coupling efficiency in real time. At the AR-HCF output, the delivered laser power and beam quality are measured at the same time after the collimating lens (L5).
3.2 Characterization of laser power delivery
Figure 3 shows the measured laser power output after transmission by 3 m AR-HCF and its corresponding coupling efficiency $\eta $ excluding the fiber attenuation, defined by
(1)$$\eta = \frac{{{P_{out}}}}{{{P_{in}}}} \cdot {10^{\frac{{aL}}{{10}}}}$$
where ${P_{out}}$ denotes the output power measured after L5 while ${P_{in}}$ the input power measured after L4, a the measured fiber attenuation (with unit of dB/m) and L the transmission length of fiber.
Fig. 3. Measured output power and coupling efficiency as function of incident laser power. The coupling efficiency is defined by Eq. (1).
Fig. 4. Beam profiles and corresponding M2 factors of the incident laser beam (upper row) and output at the end of AR-HCF (lower row) for different laser powers.
We demonstrate the delivery of a maximum 300 W laser power measured at AR-HCF output for 1 hour, while over ten hours' delivery was demonstrated without observing fiber damage or coating burning for incident powers ranging from 50 W to 280 W. In the experiment, the optimized coupling efficiency was 81% for low incident powers below 100 W and gradually dropped to around 78.6% at 400 W input power.
When the laser was switched on at high power, a noticeable thermal drifting of XYZ stage was observed due to the heating by the uncoupled optical power. Such misalignment of the coupling condition could be compensated by transverse manual adjustment of the XYZ stage. In experiment we also found that with increasing incident power, the focal position moved back toward the lens which required the longitudinal manual adjustment of XYZ stage. However, these manual adjustments failed to maintain optimized coupling efficiency for high incident power. We attribute the degradation of coupling efficiency to the thermal induced lensing effects giving rise to a smaller beam size at the focus plane after L4 as discussed later.
3.3 Output beam quality from AR-HCF
The delivered laser beam profile at the AR-HCF output was characterized for different incident powers by measuring the M2 factor as shown in Fig. 4. Back-polished dielectric mirrors are used to attenuate the laser beam before the beam profiler (HP-LQM, Prime). Although the incident beam quality becomes slightly better as the power increases, M2 is found always above 1.5 which makes the high coupling efficiency a challenge (as discussed in Section 4.1). The numerical aperture of delivered beam is measured as 0.0326 at 30 W incident power, and rises slightly to 0.0377 at 220 W.
Our simulation shows that the fundamental mode of AR-HCF has an average leakage loss of 0.034 dB/m at 1080 nm while LP11-like mode 0.308 dB/m, corresponding to a HOM extinction ratio of about 9. Excited HOMs associated with higher losses dissipate in AR-HCF faster which assists the modal filtering effect in the laser delivery. As shown in Fig. 4, the delivered laser beam out of AR-HCF presents a near diffraction limited beam quality at low incident power below 100 W and slightly degrades for higher power implying the rising of HOMs in the transmission.
3.4 Temporal stability of laser power delivery by AR-HCF
Figure 5(a) records the temporal measurement of coupling efficiency of AR-HCF for different incident power when no manual adjustment was applied for coupling optimization. The coupling efficiency was found to stay stable for the first ten to fifteen minutes for both low and high incident power and then decrease at a different rate depending on the heat accumulation. We point out that such degraded coupling efficiency would be recovered by manually adjusting the XYZ stages. Even at high incident power, after the manual adjustment and when a thermal equilibrium status was reached, the laser delivery by AR-HCF could become stable for a period of an hour or more as shown in Fig. 5(b).
Fig. 5. Temporal measurement: (a) coupling efficiency without adjusting the XYZ stage for different incident power; (b) coupling efficiency for 200 W input power, with manual adjustment of XYZ stage at 20 and 60 minutes, respectively.
A longer time demonstration of high-power laser delivery by AR-HCF was unfortunately limited by the performance of our current laser source. As Fig. 5(b) implies, when XYZ stage and lenses reach the thermal equilibrium condition, high-power laser delivery by AR-HCF is possible to achieve for much long time, which will be explored in our future work.
4.1 Towards an improved coupling efficiency
In our experiment, we managed to achieve only 81% coupling efficiency from the free space laser beam to AR-HCF while 92% was reported in [38]. We set up an intermodal coupling model of free-space beam with AR-HCF and numerically calculate the coupling efficiency by using the finite element software COMSOL.
The coupling efficiency $\eta $ defined as the ratio of power coupled into modes of AR-HCF over the total incident beam power at the end, is given by [46]
(2)$$\eta = \frac{{{{\left|{\int\!\!\!\int {{E_i}(x,y)E_f^\ast (x,y)} dxdy} \right|}^2}}}{{[\int\!\!\!\int {{{|{{E_i}(x,y)} |}^2}} dxdy][\int\!\!\!\int {{{|{{E_f}(x,y)} |}^2}} dxdy]}}$$
where ${E_i}$ denotes the incident optical field in the fiber end-face plane while ${E_f}$ the modal profile of AR-HCF. Our AR-HCF allows HOMs with relatively low loss. In the model, we take the fundamental mode and LP11-like mode of AR-HCF into account only.
To obtain the modal field distributions of AR-HCF, we reconstructed the CAD model of AR-HCF from its SEM picture and simulated it using COMSOL. We approximately rebuild the incident laser beam field by linearly scaling the linear polarized (LP) mode expressions of the pigtail fiber of laser (Nufern LMA-GDF-20/400, core radius of 10 µm and NA of 0.065) by a factor of $\xi $. The modal field radius of LP01 mode at the fiber laser output is calculated to be 8.71 µm [47] and our coupling optics is designed to scale it up to 13 µm by $\xi = 1.\textrm{5}$ at the entrance of AR-HCF which is close to 12.75 µm the radius of the fundamental-like mode.
At 1080 nm the pigtail's normalized frequency V is about 3.782, indicating existence of LP11 modes [48]. Therefore, the incident field can be described by the superposition of LP01 and LP11 modes following [49]
(3)$${E_0}(x,y) = \sqrt {1 - \alpha } \cdot {E_{01}}(x,y) + \sqrt \alpha \cdot {e^{i\psi }}{E_{11}}(x,y)$$
where $\alpha \in [0,1]$ is the power fraction factor, and $\psi $ the phase shift between the two superimposed LP modes, which is neglected in the paper for simplification.
To evaluate the maximum coupling efficiency of our experiment in theory, we model our incident beam as a superposition of LP01 and LP11 modes to be coupled with the fundamental and LP11 like HOMs of AR-HCF only. Figures 6(a) and 6(b) show the calculated coupling efficiency as function of the incident beam size and fraction of LP11 mode among the incident beam power, respectively. For the incidence of pure LP01 mode, the highest coupling efficiency 98.46% is achieved when $\xi = 1.5$. As the LP11 mode occupies higher power ratio, the coupling efficiency would be reduced to 97.35% (α=0.5) and then 93.62% (α=1) when $\xi = 1.5$.
Fig. 6. Calculated coupling efficiency between LP modes of laser beam and modes of AR-HCF (a) for different $\xi $ when $\alpha $ equals 0, 0.5 and 1; (b) for different $\alpha $ as $\xi $ varies from 0.5 to 2.5. Noted that only the fundamental mode and LP11-like modes of AR-HCF are considered.
For an 81% coupling efficiency in the experiment, lens fabrication errors/defects, other possible sources of transmission loss, such as excitation of other HOMs of AR-HCF and fiber disuniformity could all considered to contribute to the degraded measured coupling efficiency, requiring more effort in further exploration. It is noted that the measured coupling efficiency was calibrated by the cutback attenuation that was primarily determined by the fundamental-like mode. If we include LP11-like mode of AR-HCF in the calibration and assume its attenuation about 9 times of the measured cutback loss according to our simulation, the maximum coupling efficiency of our experiment may reach as high as 93.5% (α=0.5), close to 97.35% as predicted.
4.2 Sensitivity of coupling efficiency on the thermal induced focus change
Laser induced thermal effect could result in lens deformation and change the spatial distribution of refractive index both of which cause the change of focus length accordingly [50]. In our experiment, we measured the laser induced temperature rise of lenses using a thermal imaging camera. When the laser power increases from 0 to 375 W, the temperature of the lens was found to rise from the room temperature to 42°C as shown in Fig. 7(a).
Fig. 7. (a) The temperature of the XYZ stage and lens under different radiation time. The curves with circle represent the temperature of XYZ stage which recorded by adjusting the position of fiber end to stay in the best coupling efficiency. The curves with square represent the temperature of lens (all the lenses are in the same temperature) shown in Fig. 2. Different colors represent different input power; (b) The focus shift of whole system under different temperature of lens.
According to [51], a recognised experimental value of thermal induced focus shift $\Delta f$ of fused silica lens is around 0.015 mm per 1°C for a single lens. Figure 7(b) presents the simulated focal length change of our coupling optics at different temperatures by COMSOL. The equivalent focal length of our coupling system is expected to be shorten by 1.1 mm when the temperature of lenses increases to 42°C. Therefore, the manual adjustment of XYZ stage along Z direction is required to compensate. It is noted that the reduced focal length would cause a smaller incident beam size, inevitably degrading the coupling efficiency of AR-HCF.
4.3 On use of XYZ stage
At the incident end of AR-HCF, the leaked laser power not only possibly damages the fiber itself and mount but also heats the XYZ stage giving rise to detrimental mechanical thermal drift which is regarded as the main challenge to the thermal stability of our AR-HCF delivery experiment scheme.
Without any additional cooling the XYZ stage temperature rose up to 217°C under 375 W input power as shown in Fig. 7(b). Figure 8 presents the simulated coupling efficiency as function of the transvers offset $\Delta y$ of AR-HCF end when the incident beam is assumed as the superposition of LP01 and LP11 modes ($\alpha \textrm{ = 0}\textrm{.5}$). For the optimized beam size when $\xi = 1.5$, the coupling becomes most sensitive to the transverse offset. For a larger incident beam size, the optimized coupling efficiency decreases but also less sensitive to the transverse offset. For a smaller incident beam, it is found that the maximum coupling efficiency appears off $\Delta y = \textrm{0}$, where a more efficient coupling with LP11-like mode in AR-HCF is expected.
Fig. 8. Calculated the coupling efficiency as function of transverse offset $\Delta y$ for different incident beam diameter. The incident beam is assumed as superposition of LP01 and LP11 modes with an equal power ratio ($\alpha \textrm{ = 0}\textrm{.5}$)
We demonstrate high power CW laser delivery by using uncooled 3 meters AR-HCF at 1080 nm wavelength for several hours' operation. A maximum 300 W power was successfully transmitted without damaging the fiber for operation over hours. Over 10 hours laser delivery test was also demonstrated for a broad range of incident power range without fiber damage. The delivered laser beam at the output end of AR-HCF presents an improved beam quality with a lower M2 factors than the incident beam. The laser induced thermal effects on both XYZ stages and optics are found to limit the performance of AR-HCF laser delivery and its temporal stability. In the future, both cooling method and new coupling design without XYZ stage will be explored to improve the long-term operation stability of high-power laser delivery by AR-HCF.
National Natural Science Foundation of China (61935002); Joint International Research Laboratory of Specialty Fiber Optics and Advanced Communication, Shanghai University; Key Research Program of Frontier Sciences, Chinese Academy of Sciences (ZDBS-LY- JSC020); CAS Pioneer Hundred Talents Program.
1. U. K. Tirlapur and K. König, "Targeted transfection by femtosecond laser," Nature 418(6895), 290–291 (2002). [CrossRef]
2. M. Farsari and B. N. Chichkov, "Two-photon fabrication," Nat. Photonics 3(8), 450–452 (2009). [CrossRef]
3. M. Petrarca, S. Henin, N. Berti, M. Matthews, J. Chagas, J. Kasparian, J.-P. Wolf, G. Gatti, G. Di Pirro, M. P. Anania, M. Ferrario, and A. Ghigo, "White-light femtosecond Lidar at 100 TW power level," Appl. Phys. B 114(3), 319–325 (2014). [CrossRef]
4. C. Markos, J. C. Travers, A. Abdolvand, B. J. Eggleton, and O. Bang, "Hybrid photonic-crystal fiber," Rev. Mod. Phys. 89(4), 045003 (2017). [CrossRef]
5. F. Poletti, M. N. Petrovich, and D. J. Richardson, "Hollow-core photonic bandgap fibers: technology and applications," Nat. Photonics 2(5-6), 315–340 (2013). [CrossRef]
6. C. M. Smith, N. Venkataraman, M. T. Gallagher, D. Müller, J. A. West, N. F. Borrelli, D. C. Allan, and K. W. Koch, "Low-loss hollow-core silica/air photonic bandgap fibre," Nature 424(6949), 657–659 (2003). [CrossRef]
7. J. D. Shephard, J. D. C. Jones, D. P. Hand, G. Bouwmans, J. C. Knight, and P. St. J. Russell, and B. J. Mangan, "High energy nanosecond laser pulses delivered single-mode through hollow-core PBG fibers," Opt. Express 12(4), 717–723 (2004). [CrossRef]
8. M. Michieletto, M. M. Johansen, J. K. Lyngsø, J. Lægsgaard, O. Bang, and T. T. Alkeskjold, "High-power picosecond pulse delivery through hollow core photonic band gap fibers," Proc. SPIE 9728, 97282Z (2016). [CrossRef]
9. G. Humbert, J. C. Knight, G. Bouwmans, P. S. J. Russell, D. P. Williams, P. J. Roberts, and B. J. Mangan, "Hollow core photonic crystal fibers for beam delivery," Opt. Express 12(8), 1477–1484 (2004). [CrossRef]
10. F. Couny, B. J. Mangan, A. V. Sokolov, and F. Benabid, "High Power 55 Watts CW Raman Fiber-Gas-Laser," in Conference on Lasers and Electro-Optics 2010, OSA Technical Digest (CD) (Optical Society of America, 2010), paper CTuM3.
11. D. C. Jones, C. R. Bennett, M. A. Smith, and A. M. Scott, "High-power beam transport through a hollow-core photonic bandgap fiber," Opt. Lett. 39(11), 3122–3125 (2014). [CrossRef]
12. Y. Y. Wang, X. Peng, M. Alharbi, C. F. Dutin, T. D. Bradley, F. Gérôme, M. Mielke, T. Booth, and F. Benabid, "Design and fabrication of hollow-core photonic crystal fibers for high-power ultrashort pulse transportation and pulse compression," Opt. Lett. 37(15), 3111–3113 (2012). [CrossRef]
13. K. F. Mak, J. C. Travers, N. Y. Joly, A. Abdolvand, and P. S. J. Russell, "Two techniques for temporal pulse compression in gas-filled hollowcore kagomé photonic crystal fiber," Opt. Lett. 38(18), 3592–3595 (2013). [CrossRef]
14. F. Emaury, C. F. Dutin, C. J. Saraceno, M. Trant, O. H. Heckl, Y. Y. Wang, C. Schriber, F. Gerome, T. Südmeyer, F. Benabid, and U. Keller, "Beam delivery and pulse compression to sub-50 fs of a modelocked thin-disk laser in a gas-filled kagome-type HC-PCF fiber," Opt. Express 21(4), 4986–4994 (2013). [CrossRef]
15. K. Murari, G. J. Stein, H. Cankaya, B. Debord, F. Gérôme, G. Cirmi, O. D. Mücke, P. Li, A. Ruehl, I. Hartl, K.-H. Hong, F. Benabid, and F. X. Kärtner, "Kagome-fiber-based pulse compression of mid-infrared picosecond pulses from a Ho: YLF amplifier," Optica 3(8), 816–822 (2016). [CrossRef]
16. F. Emaury, C. J. Saraceno, C. F. Dutin, Y. Y. Wang, C. Schriber, F. Gerome, T. Südmeyer, F. Benabid, and U. Keller, "Efficient femtosecond operation of a Kagome-type HC-PCF fiber at 75 W average power," in CLEO: 2013, OSA Technical Digest (online) (Optical Society of America, 2013), paper CTu3 K.1.
17. B. Resan, R. Auchli, V. Villamaina, and R. Holtz, "Dynamic fiber delivery of 3 W 160 fs pulses with photonic crystal hollow core fiber patchcord," Opt. Express 25(20), 24553–24558 (2017). [CrossRef]
18. F. Emaury, C. J. Saraceno, B. Debord, D. Ghosh, A. Diebold, F. Gèrôme, T. Südmeyer, F. Benabid, and U. Keller, "Efficient spectral broadening in the 100-W average power regime using gas-filled kagome HC-PCF and pulse compression," Opt. Lett. 39(24), 6843–6846 (2014). [CrossRef]
19. M. Andreana, T. Le, W. Drexler, and A. Unterhuber, "Ultrashort pulse Kagome hollow-core photonic crystal fiber delivery for nonlinear optical imaging," Opt. Lett. 44(7), 1588 (2019). [CrossRef]
20. S. Hädrich, J. Rothhardt, S. Demmler, M. Tschernajew, A. Hoffmann, M. Krebs, A. Liem, O. de Vries, M. Plötner, S. Fabian, T. Schreiber, J. Limpert, and A. Tünnermann, "Scalability of components for kW-level average power few-cycle lasers," Appl. Opt. 55(7), 1636–1640 (2016). [CrossRef]
21. Y. Y. Wang, N. V. Wheeler, F. Couny, P. J. Roberts, and F. Benabid, "Low loss broadband transmission in hypocycloid-core Kagome hollow-core photonic crystal fiber," Opt. Lett. 36(5), 669–671 (2011). [CrossRef]
22. A. D. Pryamikov, A. S. Biriukov, A. F. Kosolapov, V. G. Plotnichenko, S. L. Semjonov, and E. M. Dianov, "Demonstration of a waveguide regime for a silica hollow - core microstructured optical fiber with a negative curvature of the core boundary in the spectral region > 3.5 µm," Opt. Express 19(2), 1441–1448 (2011). [CrossRef]
23. F. Yu and J. C. Knight, "Spectral attenuation limits of silica hollow core negative curvature fiber," Opt. Express 21(18), 21466–21471 (2013). [CrossRef]
24. F. Yu and J. C. Knight, "Negative Curvature Hollow-Core Optical Fiber," IEEE J. Sel. Top. Quantum Electron. 22(2), 146–155 (2016). [CrossRef]
25. G. T. Jasion, T. D. Bradley, H. Sakr, J. R. Hayes, Y. Chen, A. Taranta, H. C. H. Mulvad, I. A. Davidson, N. V. Wheeler, E. R. Numkam Fokoua, W. Wang, D. J. Ricahrdson, and F. Poletti, "Recent breakthroughs in hollow core fiber technology," Proc. SPIE 11309, 1 (2020). [CrossRef]
26. F. Poletti, "Nested antiresonant nodeless hollow core fiber," Opt. Express 22(20), 1 (2014). [CrossRef]
27. W. Belardi and J. C. Knight, "Hollow antiresonant fibers with reduced attenuation," Opt. Lett. 39(7), 1853 (2014). [CrossRef]
28. M. S. Habib, J. E. Antonio-Lopez, C. Markos, A. Schülzgen, and R. Amezcua-Correa, "Single-mode, low loss hollow-core anti-resonant fiber designs," Opt. Express 27(4), 3824–3836 (2019). [CrossRef]
29. P. Uebel, M. C. Günendi, M. H. Frosz, G. Ahmed, N. N. Edavalath, J.-M. Ménard, and P. S. J. Russell, "Broadband robustly single-mode hollow-core PCF by resonant filtering of higher-order modes," Opt. Lett. 41(9), 1961–1964 (2016). [CrossRef]
30. F. Yu, P. Song, D. Wu, T. Birks, D. Bird, and J. Knight, "Attenuation limit of silica-based hollow-core fiber at mid-IR wavelengths," APL Photonics 4(8), 080803 (2019). [CrossRef]
31. D. Wu, F. Yu, and M. Liao, "Understanding the material loss of anti-resonant hollow-core fibers," Opt. Express 28(8), 11840–11851 (2020). [CrossRef]
32. R. M. Carter, F. Yu, W. J. Wadsworth, J. D. Shephard, T. Birks, J. C. Knight, and D. P. Hand, "Measurement of resonant bend loss in anti-resonant hollow core optical fiber," Opt. Express 25(17), 20612–20621 (2017). [CrossRef]
33. P. Jaworski, F. Yu, D. G. MacLachlan, R. R. J. Maier, R. R. Thomson, W. J. Wadsworth, J. C. Knight, J. D. Shephard, and D. P. Hand, "A hollow-core Negative Curvature Fibre for efficient delivery of NIR picosecond and femtosecond pulses for precision micro-machining," in Workshop on Specialty Optical Fibers and their Applications, (Optical Society of America, 2013), paper F3.3.
34. Y. Chen, Z. Wang, B. Gu, F. Yu, and Q. Lu, "Achieving a 1.5 µm fiber gas Raman laser source with about 400 kW of peak power and a 6.3 GHz linewidth," Opt. Lett. 41(21), 5118–5121 (2016). [CrossRef]
35. Z. Wang, Y. Chen, B. Gu, F. Yu, and C. Zhang, "About 400 kW Peak-Power, 7.5 GHz Linewidth, 1.5 µm Fiber Gas Raman Source," in Lasers Congress 2016 (ASSL, LSC, LAC), OSA Technical Digest (online) (Optical Society of America, 2016), paper JTu2A.13.
36. A. N. Kolyadin, G. K. Alagashev, A. D. Pryamikov, L. Mouradian, A. Zeytunyan, H. Toneyan, A. F. Kosolapov, and I. A. Bufetov, "Negative Curvature Hollow-core Fibers: Dispersion Properties and Femtosecond Pulse Delivery," Phys. Procedia 73, 59–66 (2015). [CrossRef]
37. B. Sherlock, F. Yu, J. Stone, S. Warren, C. Paterson, M. A. A. Neil, P. M. W. French, J. Knight, and C. Dunsby, "Tunable fibre-coupled multiphoton microscopy with a negative curvature fiber," J. Biophotonics 9(7), 715–720 (2016). [CrossRef]
38. P. Jaworski, F. Yu, R. R. J. Maier, W. J. Wadsworth, J. C. Knight, J. D. Shephard, and D. P. Hand, "Picosecond and nanosecond pulse delivery through a hollow-core negative curvature fiber for micro-machining applications," Opt. Express 21(19), 22742–22753 (2013). [CrossRef]
39. S. Eilzer and B. Wedel, "Hollow Core Optical Fibers for Industrial Ultra Short Pulse Laser Beam Delivery Applications," Fibers 6(4), 80 (2018). [CrossRef]
40. P. Jaworski, F. Yu, R. M. Carter, J. C. Knight, J. D. Shephard, and D. P. Hand, "High energy green nanosecond and picosecond pulse delivery through a negative curvature fiber for precision micro-machining," Opt. Express 23(7), 8498–8506 (2015). [CrossRef]
41. M. Michieletto, J. K. Lyngsø, C. Jakobsen, J. Lægsgaard, O. Bang, and T. T. Alkeskjold, "Hollow-core fibers for high power pulse delivery," Opt. Express 24(7), 7103–7119 (2016). [CrossRef]
42. F. Yu, M. Cann, A. Brunton, W. Wadsworth, and J. Knight, "Single-mode solarization-free hollow-core fiber for ultraviolet pulse delivery," Opt. Express 26(8), 10879–10887 (2018). [CrossRef]
43. S.-F. Gao, Y.-Y. Wang, W. Ding, and P. Wang, "Hollow-core negative-curvature fiber for UV guidance," Opt. Lett. 43(6), 1347–1350 (2018). [CrossRef]
44. F. Yu, M. Xu, and J. C. Knight, "Experimental study of low-loss single-mode performance in anti-resonant hollow-core fibers," Opt. Express 24(12), 12969–12975 (2016). [CrossRef]
45. P. Song, K. Y. Phoong, and D. Bird, "Quantitative analysis of anti-resonance in single-ring, hollow-core fibres," Opt. Express 27(20), 27745–27760 (2019). [CrossRef]
46. P. J. Winzer and W. R. Leeb, "Fiber coupling efficiency for random light and its applications to lidar," Opt. Lett. 23(13), 986–988 (1998). [CrossRef]
47. D. Marcuse, "Loss Analysis of Single-Mode Fiber Splices," Bell Syst. Tech. J. 56(5), 703–718 (1977). [CrossRef]
48. D. Gloge, "Weakly guiding fibers," Appl. Opt. 10(10), 2252–2258 (1971). [CrossRef]
49. H. Yoda, P. Polynkin, and M. Mansuripur, "Beam quality factor of higher order modes in a step-index fiber," J. Lightwave Technol. 24(3), 1350–1355 (2006). [CrossRef]
50. S. Faas, D. J. Foerster, R. Weber, and T. Graf, "Determination of the thermally induced focal shift of processing optics for ultrafast lasers with average powers of up to 525 W," Opt. Express 26(20), 26020–26029 (2018). [CrossRef]
51. X. Z. Liu, L. N. Liu, and J. B. Zhou, "Simulated and experimental study on temperature induced lens focal shifts," Optoelectron. Lett. 15(4), 245–249 (2019). [CrossRef]
Article Order
U. K. Tirlapur and K. König, "Targeted transfection by femtosecond laser," Nature 418(6895), 290–291 (2002).
[Crossref]
M. Farsari and B. N. Chichkov, "Two-photon fabrication," Nat. Photonics 3(8), 450–452 (2009).
M. Petrarca, S. Henin, N. Berti, M. Matthews, J. Chagas, J. Kasparian, J.-P. Wolf, G. Gatti, G. Di Pirro, M. P. Anania, M. Ferrario, and A. Ghigo, "White-light femtosecond Lidar at 100 TW power level," Appl. Phys. B 114(3), 319–325 (2014).
C. Markos, J. C. Travers, A. Abdolvand, B. J. Eggleton, and O. Bang, "Hybrid photonic-crystal fiber," Rev. Mod. Phys. 89(4), 045003 (2017).
F. Poletti, M. N. Petrovich, and D. J. Richardson, "Hollow-core photonic bandgap fibers: technology and applications," Nat. Photonics 2(5-6), 315–340 (2013).
C. M. Smith, N. Venkataraman, M. T. Gallagher, D. Müller, J. A. West, N. F. Borrelli, D. C. Allan, and K. W. Koch, "Low-loss hollow-core silica/air photonic bandgap fibre," Nature 424(6949), 657–659 (2003).
J. D. Shephard, J. D. C. Jones, D. P. Hand, G. Bouwmans, J. C. Knight, and P. St. J. Russell, and B. J. Mangan, "High energy nanosecond laser pulses delivered single-mode through hollow-core PBG fibers," Opt. Express 12(4), 717–723 (2004).
M. Michieletto, M. M. Johansen, J. K. Lyngsø, J. Lægsgaard, O. Bang, and T. T. Alkeskjold, "High-power picosecond pulse delivery through hollow core photonic band gap fibers," Proc. SPIE 9728, 97282Z (2016).
G. Humbert, J. C. Knight, G. Bouwmans, P. S. J. Russell, D. P. Williams, P. J. Roberts, and B. J. Mangan, "Hollow core photonic crystal fibers for beam delivery," Opt. Express 12(8), 1477–1484 (2004).
F. Couny, B. J. Mangan, A. V. Sokolov, and F. Benabid, "High Power 55 Watts CW Raman Fiber-Gas-Laser," in Conference on Lasers and Electro-Optics 2010, OSA Technical Digest (CD) (Optical Society of America, 2010), paper CTuM3.
D. C. Jones, C. R. Bennett, M. A. Smith, and A. M. Scott, "High-power beam transport through a hollow-core photonic bandgap fiber," Opt. Lett. 39(11), 3122–3125 (2014).
Y. Y. Wang, X. Peng, M. Alharbi, C. F. Dutin, T. D. Bradley, F. Gérôme, M. Mielke, T. Booth, and F. Benabid, "Design and fabrication of hollow-core photonic crystal fibers for high-power ultrashort pulse transportation and pulse compression," Opt. Lett. 37(15), 3111–3113 (2012).
K. F. Mak, J. C. Travers, N. Y. Joly, A. Abdolvand, and P. S. J. Russell, "Two techniques for temporal pulse compression in gas-filled hollowcore kagomé photonic crystal fiber," Opt. Lett. 38(18), 3592–3595 (2013).
F. Emaury, C. F. Dutin, C. J. Saraceno, M. Trant, O. H. Heckl, Y. Y. Wang, C. Schriber, F. Gerome, T. Südmeyer, F. Benabid, and U. Keller, "Beam delivery and pulse compression to sub-50 fs of a modelocked thin-disk laser in a gas-filled kagome-type HC-PCF fiber," Opt. Express 21(4), 4986–4994 (2013).
K. Murari, G. J. Stein, H. Cankaya, B. Debord, F. Gérôme, G. Cirmi, O. D. Mücke, P. Li, A. Ruehl, I. Hartl, K.-H. Hong, F. Benabid, and F. X. Kärtner, "Kagome-fiber-based pulse compression of mid-infrared picosecond pulses from a Ho: YLF amplifier," Optica 3(8), 816–822 (2016).
F. Emaury, C. J. Saraceno, C. F. Dutin, Y. Y. Wang, C. Schriber, F. Gerome, T. Südmeyer, F. Benabid, and U. Keller, "Efficient femtosecond operation of a Kagome-type HC-PCF fiber at 75 W average power," in CLEO: 2013, OSA Technical Digest (online) (Optical Society of America, 2013), paper CTu3 K.1.
B. Resan, R. Auchli, V. Villamaina, and R. Holtz, "Dynamic fiber delivery of 3 W 160 fs pulses with photonic crystal hollow core fiber patchcord," Opt. Express 25(20), 24553–24558 (2017).
F. Emaury, C. J. Saraceno, B. Debord, D. Ghosh, A. Diebold, F. Gèrôme, T. Südmeyer, F. Benabid, and U. Keller, "Efficient spectral broadening in the 100-W average power regime using gas-filled kagome HC-PCF and pulse compression," Opt. Lett. 39(24), 6843–6846 (2014).
M. Andreana, T. Le, W. Drexler, and A. Unterhuber, "Ultrashort pulse Kagome hollow-core photonic crystal fiber delivery for nonlinear optical imaging," Opt. Lett. 44(7), 1588 (2019).
S. Hädrich, J. Rothhardt, S. Demmler, M. Tschernajew, A. Hoffmann, M. Krebs, A. Liem, O. de Vries, M. Plötner, S. Fabian, T. Schreiber, J. Limpert, and A. Tünnermann, "Scalability of components for kW-level average power few-cycle lasers," Appl. Opt. 55(7), 1636–1640 (2016).
Y. Y. Wang, N. V. Wheeler, F. Couny, P. J. Roberts, and F. Benabid, "Low loss broadband transmission in hypocycloid-core Kagome hollow-core photonic crystal fiber," Opt. Lett. 36(5), 669–671 (2011).
A. D. Pryamikov, A. S. Biriukov, A. F. Kosolapov, V. G. Plotnichenko, S. L. Semjonov, and E. M. Dianov, "Demonstration of a waveguide regime for a silica hollow - core microstructured optical fiber with a negative curvature of the core boundary in the spectral region > 3.5 µm," Opt. Express 19(2), 1441–1448 (2011).
F. Yu and J. C. Knight, "Spectral attenuation limits of silica hollow core negative curvature fiber," Opt. Express 21(18), 21466–21471 (2013).
F. Yu and J. C. Knight, "Negative Curvature Hollow-Core Optical Fiber," IEEE J. Sel. Top. Quantum Electron. 22(2), 146–155 (2016).
G. T. Jasion, T. D. Bradley, H. Sakr, J. R. Hayes, Y. Chen, A. Taranta, H. C. H. Mulvad, I. A. Davidson, N. V. Wheeler, E. R. Numkam Fokoua, W. Wang, D. J. Ricahrdson, and F. Poletti, "Recent breakthroughs in hollow core fiber technology," Proc. SPIE 11309, 1 (2020).
F. Poletti, "Nested antiresonant nodeless hollow core fiber," Opt. Express 22(20), 1 (2014).
W. Belardi and J. C. Knight, "Hollow antiresonant fibers with reduced attenuation," Opt. Lett. 39(7), 1853 (2014).
M. S. Habib, J. E. Antonio-Lopez, C. Markos, A. Schülzgen, and R. Amezcua-Correa, "Single-mode, low loss hollow-core anti-resonant fiber designs," Opt. Express 27(4), 3824–3836 (2019).
P. Uebel, M. C. Günendi, M. H. Frosz, G. Ahmed, N. N. Edavalath, J.-M. Ménard, and P. S. J. Russell, "Broadband robustly single-mode hollow-core PCF by resonant filtering of higher-order modes," Opt. Lett. 41(9), 1961–1964 (2016).
F. Yu, P. Song, D. Wu, T. Birks, D. Bird, and J. Knight, "Attenuation limit of silica-based hollow-core fiber at mid-IR wavelengths," APL Photonics 4(8), 080803 (2019).
D. Wu, F. Yu, and M. Liao, "Understanding the material loss of anti-resonant hollow-core fibers," Opt. Express 28(8), 11840–11851 (2020).
R. M. Carter, F. Yu, W. J. Wadsworth, J. D. Shephard, T. Birks, J. C. Knight, and D. P. Hand, "Measurement of resonant bend loss in anti-resonant hollow core optical fiber," Opt. Express 25(17), 20612–20621 (2017).
P. Jaworski, F. Yu, D. G. MacLachlan, R. R. J. Maier, R. R. Thomson, W. J. Wadsworth, J. C. Knight, J. D. Shephard, and D. P. Hand, "A hollow-core Negative Curvature Fibre for efficient delivery of NIR picosecond and femtosecond pulses for precision micro-machining," in Workshop on Specialty Optical Fibers and their Applications, (Optical Society of America, 2013), paper F3.3.
Y. Chen, Z. Wang, B. Gu, F. Yu, and Q. Lu, "Achieving a 1.5 µm fiber gas Raman laser source with about 400 kW of peak power and a 6.3 GHz linewidth," Opt. Lett. 41(21), 5118–5121 (2016).
Z. Wang, Y. Chen, B. Gu, F. Yu, and C. Zhang, "About 400 kW Peak-Power, 7.5 GHz Linewidth, 1.5 µm Fiber Gas Raman Source," in Lasers Congress 2016 (ASSL, LSC, LAC), OSA Technical Digest (online) (Optical Society of America, 2016), paper JTu2A.13.
A. N. Kolyadin, G. K. Alagashev, A. D. Pryamikov, L. Mouradian, A. Zeytunyan, H. Toneyan, A. F. Kosolapov, and I. A. Bufetov, "Negative Curvature Hollow-core Fibers: Dispersion Properties and Femtosecond Pulse Delivery," Phys. Procedia 73, 59–66 (2015).
B. Sherlock, F. Yu, J. Stone, S. Warren, C. Paterson, M. A. A. Neil, P. M. W. French, J. Knight, and C. Dunsby, "Tunable fibre-coupled multiphoton microscopy with a negative curvature fiber," J. Biophotonics 9(7), 715–720 (2016).
P. Jaworski, F. Yu, R. R. J. Maier, W. J. Wadsworth, J. C. Knight, J. D. Shephard, and D. P. Hand, "Picosecond and nanosecond pulse delivery through a hollow-core negative curvature fiber for micro-machining applications," Opt. Express 21(19), 22742–22753 (2013).
S. Eilzer and B. Wedel, "Hollow Core Optical Fibers for Industrial Ultra Short Pulse Laser Beam Delivery Applications," Fibers 6(4), 80 (2018).
P. Jaworski, F. Yu, R. M. Carter, J. C. Knight, J. D. Shephard, and D. P. Hand, "High energy green nanosecond and picosecond pulse delivery through a negative curvature fiber for precision micro-machining," Opt. Express 23(7), 8498–8506 (2015).
M. Michieletto, J. K. Lyngsø, C. Jakobsen, J. Lægsgaard, O. Bang, and T. T. Alkeskjold, "Hollow-core fibers for high power pulse delivery," Opt. Express 24(7), 7103–7119 (2016).
F. Yu, M. Cann, A. Brunton, W. Wadsworth, and J. Knight, "Single-mode solarization-free hollow-core fiber for ultraviolet pulse delivery," Opt. Express 26(8), 10879–10887 (2018).
S.-F. Gao, Y.-Y. Wang, W. Ding, and P. Wang, "Hollow-core negative-curvature fiber for UV guidance," Opt. Lett. 43(6), 1347–1350 (2018).
F. Yu, M. Xu, and J. C. Knight, "Experimental study of low-loss single-mode performance in anti-resonant hollow-core fibers," Opt. Express 24(12), 12969–12975 (2016).
P. Song, K. Y. Phoong, and D. Bird, "Quantitative analysis of anti-resonance in single-ring, hollow-core fibres," Opt. Express 27(20), 27745–27760 (2019).
P. J. Winzer and W. R. Leeb, "Fiber coupling efficiency for random light and its applications to lidar," Opt. Lett. 23(13), 986–988 (1998).
D. Marcuse, "Loss Analysis of Single-Mode Fiber Splices," Bell Syst. Tech. J. 56(5), 703–718 (1977).
D. Gloge, "Weakly guiding fibers," Appl. Opt. 10(10), 2252–2258 (1971).
H. Yoda, P. Polynkin, and M. Mansuripur, "Beam quality factor of higher order modes in a step-index fiber," J. Lightwave Technol. 24(3), 1350–1355 (2006).
S. Faas, D. J. Foerster, R. Weber, and T. Graf, "Determination of the thermally induced focal shift of processing optics for ultrafast lasers with average powers of up to 525 W," Opt. Express 26(20), 26020–26029 (2018).
X. Z. Liu, L. N. Liu, and J. B. Zhou, "Simulated and experimental study on temperature induced lens focal shifts," Optoelectron. Lett. 15(4), 245–249 (2019).
Abdolvand, A.
Ahmed, G.
Alagashev, G. K.
Alharbi, M.
Alkeskjold, T. T.
Allan, D. C.
Amezcua-Correa, R.
Anania, M. P.
Andreana, M.
Antonio-Lopez, J. E.
Auchli, R.
Bang, O.
Belardi, W.
Benabid, F.
Bennett, C. R.
Berti, N.
Bird, D.
Biriukov, A. S.
Birks, T.
Booth, T.
Borrelli, N. F.
Bouwmans, G.
Bradley, T. D.
Brunton, A.
Bufetov, I. A.
Cankaya, H.
Cann, M.
Carter, R. M.
Chagas, J.
Chichkov, B. N.
Cirmi, G.
Couny, F.
Davidson, I. A.
de Vries, O.
Debord, B.
Demmler, S.
Di Pirro, G.
Dianov, E. M.
Diebold, A.
Ding, W.
Drexler, W.
Dunsby, C.
Dutin, C. F.
Edavalath, N. N.
Eggleton, B. J.
Eilzer, S.
Emaury, F.
Faas, S.
Fabian, S.
Farsari, M.
Ferrario, M.
Foerster, D. J.
French, P. M. W.
Frosz, M. H.
Gallagher, M. T.
Gao, S.-F.
Gatti, G.
Gerome, F.
Gérôme, F.
Gèrôme, F.
Ghigo, A.
Ghosh, D.
Gloge, D.
Graf, T.
Gu, B.
Günendi, M. C.
Habib, M. S.
Hädrich, S.
Hand, D. P.
Hartl, I.
Hayes, J. R.
Heckl, O. H.
Henin, S.
Hoffmann, A.
Holtz, R.
Hong, K.-H.
Humbert, G.
Jakobsen, C.
Jasion, G. T.
Jaworski, P.
Johansen, M. M.
Joly, N. Y.
Jones, D. C.
Jones, J. D. C.
Kärtner, F. X.
Kasparian, J.
Keller, U.
Knight, J.
Knight, J. C.
Koch, K. W.
Kolyadin, A. N.
König, K.
Kosolapov, A. F.
Krebs, M.
Lægsgaard, J.
Le, T.
Leeb, W. R.
Li, P.
Liao, M.
Liem, A.
Limpert, J.
Liu, L. N.
Liu, X. Z.
Lu, Q.
Lyngsø, J. K.
MacLachlan, D. G.
Maier, R. R. J.
Mak, K. F.
Mangan, B. J.
Mansuripur, M.
Marcuse, D.
Markos, C.
Matthews, M.
Ménard, J.-M.
Michieletto, M.
Mielke, M.
Mouradian, L.
Mücke, O. D.
Müller, D.
Mulvad, H. C. H.
Murari, K.
Neil, M. A. A.
Numkam Fokoua, E. R.
Paterson, C.
Peng, X.
Petrarca, M.
Petrovich, M. N.
Phoong, K. Y.
Plötner, M.
Plotnichenko, V. G.
Poletti, F.
Polynkin, P.
Pryamikov, A. D.
Resan, B.
Ricahrdson, D. J.
Richardson, D. J.
Roberts, P. J.
Rothhardt, J.
Ruehl, A.
Russell, P. S. J.
Sakr, H.
Saraceno, C. J.
Schreiber, T.
Schriber, C.
Schülzgen, A.
Scott, A. M.
Semjonov, S. L.
Shephard, J. D.
Sherlock, B.
Smith, C. M.
Smith, M. A.
Sokolov, A. V.
Song, P.
St. J, P.
Stein, G. J.
Stone, J.
Südmeyer, T.
Taranta, A.
Thomson, R. R.
Tirlapur, U. K.
Toneyan, H.
Trant, M.
Travers, J. C.
Tschernajew, M.
Tünnermann, A.
Uebel, P.
Unterhuber, A.
Venkataraman, N.
Villamaina, V.
Wadsworth, W.
Wadsworth, W. J.
Wang, P.
Wang, W.
Wang, Y. Y.
Wang, Y.-Y.
Wang, Z.
Warren, S.
Weber, R.
Wedel, B.
West, J. A.
Wheeler, N. V.
Williams, D. P.
Winzer, P. J.
Wolf, J.-P.
Wu, D.
Xu, M.
Yoda, H.
Yu, F.
Zeytunyan, A.
Zhang, C.
Zhou, J. B.
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(1) η = P o u t P i n ⋅ 10 a L 10
(2) η = | ∫ ∫ E i ( x , y ) E f ∗ ( x , y ) d x d y | 2 [ ∫ ∫ | E i ( x , y ) | 2 d x d y ] [ ∫ ∫ | E f ( x , y ) | 2 d x d y ]
(3) E 0 ( x , y ) = 1 − α ⋅ E 01 ( x , y ) + α ⋅ e i ψ E 11 ( x , y )
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text:
layout: single
# Should be default already
permalink: /positions/Computer_Wizards/
title: Computer Wizards for GAO Group

author_profile: true

date: 2018-03-19
last_modified_at: 2018-03-19
---

_**Please read before applying, non-complicance will render application void and reflects poorly on you:**_

GAO is looking for Computer Wizards for full-time summer or LOA internship positions.

### Highlight of the Role:
You get to learn from the best, mingle with the best, and be on the forefront of developing the most cutting-edge solutions.

### Job Scope:
Jobs at GAO will be split up into modules, the Intern should be able to:-
 1. Execute ideas into fruition with speed and accuracy. (You will have large amounts of input into the architecture and design of the various modules.)
 2. Manage and distill large amounts of unstructured data into usable output.
 3. Be able to present the output of work done into usable format for non-tech savvy users.

### Job Requirements:
The Intern should:
 1. Be in the process of completing a degree in one of the following fields: Computer Science, Mathematics, Statistics, Data Science, or Applied Mathematics
 2. Have significant programming experience in at least one of the following programming languages and understand its best practices:
    - a. Python (preferred)
    - b. JavaScript (ES6)
    - c. Ruby
 3. Know how to use Git
 4. Have experience in web development using at least one of the following web development frameworks:
    - a. Python and Django (preferred)
    - b. Ruby on Rails
    - c. Node.js
 5. [Bonus] Strong knowledge in Data Structures and database design.
 6. [Optional] Be familiar with/willing to learn:
    - a. Docker and Kubernetes
    - b. React.js and ReactNative
    - c. Python libraries such as Celery, TensorFlow, Theano, nltk, scikit-learn, etc.

Qualified candidates should possess the willingness to work hard in an unstructured environment where initiative and enthusiasm for learning are highly valued. Strong communication skills are essential.

### How to apply:
- Please indicate the Job Title as the Header of the email.
- Please attach a **PDF** copy of your resume.
- Please attach an unofficial school transcript.
- Indicate your level of programming experience, especially in the languages and frameworks that we highlighted in 'Requirements'.
  - a. Please be specific and give examples. Tell us about the projects or coursework you completed that use these programming languages.
  - b. If you have significant experience in programming languages outside of those mentioned in 'Requirements' (e.g. C, C++, Java, Haskell, Clojure, Go, Perl, etc.), please include them.
- Share a link to your GitHub page.
- Please send your cover letter and indicate your start date availability.
- If you were referred or recommended by a previous GAO Alum, please indicate in your email as well.

_**OPTIONAL**_
-

### Suggested preparation:
- Be familiar with basic networking concepts such as DNS. DHCP servers, difference between L1, L2, L3 switches and how to configure hardware and networking equipment.
- Be familiar with the different Cloud Computing Platforms and architectures such as AWS, GCP, Azure, Heroku, etc.
- Be familiar with linux operating systems.  Basic knowledge of using Linux such as Ubuntu is a must!  Extra points if you are able to use other operating systems such as ArchLinux, other Fedora or Debian variants, OpenBSD, FreeBSD, etc.  Being able to configure and setup in Windows is also a must.  If you are only able to program on a Macintosh we are probably not a good fit for you.

### Recommended reading list (links to amazon.com):
Most Knowledge can be found online but here are some Programming Books
- [Two Scoops of Django](https://www.twoscoopspress.com/products/two-scoops-of-django-1-11)
You might want to read the other Finance Books we recommend to other Interns since you might need to be familiar with the terminology.
- [The Little Book of Hedge Funds](https://www.amazon.com/Little-Book-Hedge-Funds/dp/1118099672)
- [Market Wizards](https://www.amazon.com/Market-Wizards-Interviews-Top-Traders/dp/0135560934)

### Further notes:
- Criteria and selections for the posting is at the sole discretion of the employer and shortlisted candidates will be contacted directly.
- Please note that only shortlisted candidates will be notified and applications will be considered on a rolling basis.
- Please do not hesitate to contact your career advisor for any assistance.