Participant: Yuhang, Matteo, Eleonora, Aritomi

We checked many things and want to figure out why we have a 300kHz peak in the spectrum of homodyne.

We tried to remove green by putting line filter(1064nm), tried to investigate the locking of OPO, tried to see the effect of leaked p-pol to homodyne. Finally, we confirmed the problem comes from the coherent control beam directly.

Then we found the noise eater doesn't give any difference when we switch on/off noise eater. So we suspected that this is because we are using not enough power of cc laser. This guess is mainly from the remind of Chienming. Then we tried to increase the cc power. We found the peak disappeared after going beyond a current value of ~1.2A. So we confirmed that increasing the current value above ~1.2A can engage the noise eater.

Then we set the current value of 1.305 and temperature of 34.37 degrees for cc laser. This is done by compromising available ND filters, desirable value 15mW of IR after filters and the avoid of mode hop. As we know, we lose alignment each time after putting the ND filter. We also recovered alignment. The alignment situation is attached in figure 1. We will keep this setting for the future until we find additional problem.