This entry is log on May 28.
As I could not align the cavity with folded geometry and see the transmitted light, I decided to play with FP geometry to confirm whether the fused silica mirrors are O.K. or not.
The cavity length was set to 6.4 cm.
Actually, I could see the transmitted beam easily.
After that, I estimated the finesse by scanning the laser frequency.
The measured value was about 1.46*104 where the designed value was 1.5*104.
Therefore, the fused silica mirrors seemed to be O.K.
Next step is to lock the laser to this FP cavity and then I will try with folded cavity with shorter cavity length.