I wrote a script which scans the laser slow control voltage and records the transmission power. Last night, we scaned the lasers over the entire -10 to 10 volt laser slow control for both cavities looking for 00 mode resonances. I scanned from -10 to 10 volts using increments of 0.0001 at a step rate of 10 Hz.
The laser is not given much time to thermalize, so the resonance voltage values reported in the plots below are not 100% accurate, but they give a good ballpark (in a test I ran, the reported value of the resonance is around 0.003 volts greater than it's true value at this increment value and step rate.)
Recall that the FSR of our L=3.67cm cavities is around 4 GHz. Each of the tallest peaks representing a 00 mode resonating in the cavity should be separated by this frequency as the laser frequency changes.
Next step is to find two of these modes which produce a beatnote in a "stable" laser region as examined in elog 1863, locked the cavities, and look for a transmission beatnote.
Also attached is a tar containing (1) the data, (2) the plots, and (3) the python scripts used to take the data on acromag2 (CavityResonancesFinder.py) and plot the data (txtPlotter.py).
Linear Y-axis on a cavity scan!!! Ahhhhhh, no!!!! https://www.mathsisfun.com/algebra/logarithms.html