While doing our today's work (21564), we increased the input laser power from the PSL room to IMC and the following interferometer by rotating the HWP in front of the final periscope on the PSL table. Thanks to the encoder, the power-up/down and the HWP rotation seemed stable; as far as I did 1deg rotation to 0.3W change, but as you know the repsonse of a HWP should be sine so someone should once measure the wider range of the response; although there is a report on the working of this setup (20236), it seemed no one would measure such global response.

The IMC/PMC locking logic seems to tolerate this kind of power increasing while being locked.

Anyway, today we just increased the power from 4W to 6 W or so read by K1:LAS-POW_PSL2_OUT16 (seen at the foot of the final periscope in the PSL room), which is much diffrerent from the read by K1:LAS-POW_IMC_DC_OUT16 (usually shown in the IMC MEDM, wihch is calculated from the sum of the reflection and transmission of IMC), as found in the attached figure, and so this inconsistenct has to be fixed in the end for the upcoming commissioining.

I maybe too much reduced the power after I tested this function.