After adjusted the waveplate and the EOM, we adjust the Faraday Isolator today to get more power transmit. Now more than half of the power can reach the cavity.
There are some problems we need to fixed,
1. The crystal is not fixed, when we try to get the mode matching, sometimes cannot avoid touch the cavity, then we lost everything. Matteo did the alignment many times in few hours working.
2.There are too many green reflected back, the maximum efficiency we got is about 17%, with a input infrared power of 670mW, and output green of 119mW, when the cavity is locked. But there are at least four reflect green beam on the mirror before the dichoric mirror, we are able to measure two of them, one has 1-2 mW power, the other has 4mW.
3. The green beam has some fringe on it, so this maybe means there is not only one green beam come out from the cavity, but we are not sure.
After first time we got a efficiency of about 16%, we break the lock and wait for twenty minutes to see if the system is stable or not. When we try to lock it again 20min later, the output of green is almost the same with some tiny re-alignment.