How do you calibrate this to Hz/rtHz?
I measured the RC transmitted light signals here at the 40m. I made all connections through the PSL patch panel. No optics/PD were touched.
I measured the spectral density of the signal of the transmitted beam behind RefCav in both time and frequency domain.
This will be compared with the result from PSL lab later, so I can see how stable the signal should be.
We re-aligned the beam into the cavity (the DC level increased from 2 V to 3.83V)
and the reflected beam to the center of the RFPD.