Progress of 16th and 17th

We found out the beam we are looking at is not clear enough, it will be harder to do the alignment with that, so I adjusted the camera and also the beam path. From the first picture, it is the beam path that if we want to look at the beam directly with CCD, I lower the camera instead of bending the holder which will make the situation more complicated. The second picture shows what we have now with CCD. It seems the higher order beam is in horizontal direction but the mode is a liitle bit strange. And before if we use the camera with the camera lens, and use the camera to look at the card, the beam is quiet small. So I changed the lens to make the beam larger and have more details of the beam. But then I found out that instead one beam, there were two separate spots on the card.( I didn't get very good picture to show this.) And first I thought it may be the TEM01 mode, but if it is, the pattern should be like one round spot cutting into two, but what I saw it two round spots and there is some distance between them. The other guess is that it is the reflection in the cavity, which means that the beam path inside the cavity is not overlap with the line between the center of miniscope and crystal.But when I drove the PZT, the distance between the two spot seems not change. So I am not sure where the two spots came from.