Since we received the mirror from Thorlabs BST11. We replaced this mirror with the mirror we replaced the day before.
1. We recovered the alignment of SHG. We increased the laser current and recovered the green production. Now the power after EOM is 53mW. This recover is also done by a better alignment. We found a mode hop between 1.2A and 1.34A. We also recovered the lock of filter cavity.
2. We did the characterization of transmission beam of BST11. The measurement of beam size is quite collamited with a beam dimension of around 1950um in diameter(we put a lens of 50mm). I did the simulation, the initial beam should be 17.5um in radius. (See attached picture).
| simulation of optocad | 9um |
| simulation of jammt | 12.6um |
| measurement | 17.5um |
We also found astigmatism and we solved this by rotating lens. However, now the tilt of 50mm lens is very large, like 30 degrees.
