J. Kissel, K. Izumi

We have successfully mapped the IR beam into HAM4. In order to do so, we've increased the laser power to 1 [W] (see below for process / details). We've now handed off further alignment of ITMX, BS, and SRs to Betsy & Travis.

- Power meter reading after temporary half-wave plate just before PSL periscope before power increase before change: 202 [mW].
- PSL Monitor PD (IO_AB_PD2) reading ~20 [ct].
- Re-confirmed bypass path is aligned looking at IM4 trans wall-spot position, and IM4 trans QPD. Good; check.
- Confirmed MC3 is blocked with metal protection plate -- only IMC bypass beam continues through to IFO. No light resonant in IMC.
- Moved PRM to parking position P = -107; Y = -5707 (see LHO aLOG 9377)
- Unlocked/untagged power control of rotation stage, energized rotation stage.
- Tried using temporary half-wave plate just before final PSL periscope to increase power via polarization, but transmission was already at maximum (as measured by IR card at PR2 in HAM3).
- Changed rotation stage angle to 72.25 [deg] via MEDM
- Power meter reading after half-wave plate after power increase after change: 1.08 [W]
- Monitor periscope PD is at ~125 [ct]
- For the record -- beam looks dreadfully mis-centered (withing 1 [beam diameter]) of light pipe edge in yaw (though this has not been changed, and alignment into IMC was confirmed good yesterday).
- De-energized rotation stage, locked/tagged power control of rotation stage.