We preparing optics for the new layout. To reduce scattering noise, most of the Y1-1064 mirrors we have been using will be replaced by super polished mirrors.
We think Y1-1064 mirrors can cause scattering noise in the setup because the coating surfaces look very milky.
fig1: Y1-1064 mirror.
We have ~ 10-20 super polished mirrors. Some of them are good, some of them are rejected from the site. The good one will be used for periscope/ beat setup. I tested a couples of the rejected mirrors, but they can reflect both p and s beams with high efficiency. We will ask Peter to find out what is wrong with them.
fig2: Left and right, super polished mirror.
fig3: left, mirrors' case, right, certificate.
I have cleaned about half of the required optics, I think we should be able to lock the first cavity before next Wednesday.