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Nick Brewer: Difference between revisions
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After a playing around with the lock a little bit we eventually got the cavity locked to the laser and at one point saw ~9 mW of green (from 65 mW of IR). Because the crystal is birefringent, the error signal now looks like what they describe in [http://web.a.ebscohost.com.ezproxy.library.wisc.edu/ehost/pdfviewer/pdfviewer?sid=e026a4e2-3678-4737-8099-605202ad6264%40sessionmgr4005&vid=2&hid=4214 Vainio's] paper. The output isn't super stable when we look at it with an oscilloscope. Also, since we put the crystal in it seems like the peaks jump around instead of drifting around more slowly like they did before, so that might be hurting the lock. Zach is also adding in a fast feedback to the laser current.
<!--I'm also interested in measuring how well the cavity is mode matched. According to Jinlu's thesis there are three things you have to measure:
* The input coupler reflectivity with the cavity blocked
* The finesse of the cavity to determine |g| using <math>F=\frac{\pi\sqrt{g}}{1-|g|}</math>
* The reflection dip percentage <math>\eta=1-\frac{I_R}{I_{in}}</math>
-->
The polarization that generates the most green is vertical, I determined that with a Glan Taylor polarizer. We determined that in order to properly align the cavity we need to have the temperature far out of tune so we can see the cavity peaks produced from the vertical polarization.
'''5/9/14'''
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