The fluorescence is detected with a photomultiplier and a high speed data acquisition card, while the laser light is monitored by a photodiode, and both signals are handled by a LabVIEW program for further analysis.  The LabVIEW program is used to determine the location of the OH excited line according to the fluorescence intensity of OH radical when the frequency of the dye laser is scanned. 
LabVIEW
The fluorescence is detected with a photomultiplier and a high speed data acquisition card, while the laser light is monitored by a photodiode, and both signals are handled by a LabVIEW program for further analysis.  The LabVIEW program is used to determine the location of the OH excited line according to the fluorescence intensity of OH radical when the frequency of the dye laser is scanned. 
LabVIEW program
The data acquisition card is triggered by a positive TTL pulse generated by a digital delay generator, which is triggered by a rising edge of a synchronized output pulse of the dye laser. 
digital delay generator