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David Notebook: Difference between revisions
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==Things to Do/Check==
*Get a really big lens before the 633 detection photodiode.
*Measure 780 power before and after cavity; see changes with cavity piezo
*What's wrong with the IR viewer?
==Daily Log==
'''7/3/14'''
Had some difficulty with the 1064 beam today, see [[David_Notebook#1064_Laser_Notes|1064 laser notes]]. I also realized that even after getting the HeNe laser going through the cavity and hitting the diffraction grating, there was still a fair amount of play with the mirror walks which ultimately could move the beam at the photodiode by a couple inches. The generated 633 beam might be missing the detector then. I put two irises in the 780 beam path after the cavity and separated by a couple feet of path length. After lining up the iris to the 780 beam, I swapped in the HeNe and used its mirror walk (which is independent of the 780 path) to align through both irises and then put the photodiode and lens in this beam path. Hopefully the generated 633 beam will be overlapped with the HeNe path now and is hitting the photodiode. Maybe try using a very large diameter lens before the photodiode so there's more tolerance?
'''7/2/14'''
'''5/15/14'''
==1064 Laser Notes==
'''7/3/14''' Threshold test seemed off yesterday and was very off today. There is usually around 100 μW at 20 mA of current, but it took about 26 mA today and the laser was very multimode. Adjusting the grating position ultimately resolved the problem. The current reading on the driver is sometimes fluctuating, usually just by .1 mA, but sometimes by up to 5 mA. This doesn't seem to be causing any problems right now, but it is unclear why this is happening.
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