Olli, Justin and Volker
Task: Set power at bottom of the PSL periscope to 200mW and rotate the polarization by 90 deg to resonate in the low finesse mode of the IMC.
The HWP for the main power control was "unlocked/untagged" and energized outside of the PSL enclosure.
First we measured the power after the TFP after the PMC. Initial value 20.5W.
Next we turned to the main power contro stage. While temporarily turning the power after the TFP down to 200mW we assured that the main power stage HWP is set to a value that dumps most of the power. After that we maximized the power after the TFP after the PMC to 23.1W (HWP turned to 208deg).
Now the power at the bottom of the periscope was set to 205mW by rotating the main power control HWP to 63deg.
Currently there is a HWP at the pottom of the periscope to control the polarization after the power control stage. Using this HWP the polarization was rotated to "p" to operate the IMC in low finesse mode. The angle of this HWP is now set to 46 deg.
We verified that the polarization is rotated by 90 degree using an additional PBS.
Finally, the HWP for the main power control was "locked/tagged" and deenergized outside of the PSL enclosure.