lip pits (congenital lip fistulas), n.pl the congenital depressions, usually bilateral and symmetrically placed, on the vermilion portion of the lower lip. These pits may be circular or may be present as a transverse slit. The depression represents a blind fistula that penetrates downward into the lower lip to a depth of 0.5 to 2.5 cm. They often exude viscid saliva on pressure.
This resulted in the introduction of three new laser classes (1M, 2M and 3R) and the abolition of Class 3A. Below is a brief description of each of the current laser classes. The 60825-1 standards apply equally to lasers and LEDs. In most places we have used the word laser, but it can be replaced by LED. Generally speaking LEDs would be in the lower Classes (1, 1M, 2, 2M, 3R), but very exceptionally may be Class 3B.
From Wikipedia, the free encyclopedia. A fiber laser or fibre laser is a laser in which the active gain medium is an optical fiber doped with rare-earth elements such as erbium, ytterbium, neodymium, dysprosium, praseodymium, and thulium.They are related to doped fiber amplifiers, which provide light amplification without lasing.any high-power fiber lasers are based on double-clad fiber. The gain medium forms the core of the fiber, which is surrounded by two layers of cladding. The lasing mode propagates in the core, while a multimode pump beam propagates in the inner cladding layer. The outer cladding keeps this pump light confined.