Naoki, Daniel, Nutsinee
We moved MR20 and MR21 two holes to the left to make room for the new 24 MHz EOM that will now be used to lock the SHG. We're 87% mode matched to the SHG. The higher order mode is dominated by the donut mode (mode mismatch).
Also attached a function generator settings for the Thorlabs PZT driver so we don't have to figure this out next time.
Naoki, Daniel, Nutsinee
We sucessfully switched to 24.1 Hz locking for the SHG. We gained about a factor of 5 in error signal Vpp. SHG common mode gain was set to 5 dB before, now it's -8 dB. The locking sign is also flipped. Naoki put the new gain in the SHG Guardian and accepted the SDF.
According to the data sheet the modulation index coefficient is 0.14-0.16 Γ/Vpp. Assuming we have around 13dBm of 24.1MHz available at the EOM, we excpect Γ~0.42 (or about 9% of the laser power in RF). This seems a lot.
A 10dB attenuator has been added to the modulation input to reduce the modulation index by ~3.