Lisa, Kiwamu, Alexa, Sheila, Elli, Evan
The matrix element for REFLAIR_A_RF9I → SRCL has been adjusted from −8.8 to −3.75. The procedure was as follows:
After the sensing matrix adjustments, we measured the OLTFs of PRCL, MICH, and SRCL. Plots and data are attached.
Note that the PSL power may have been slightly low here because the rotation stage didn’t restore the nominal power completely. So the optical gains during nominal PSL power may be a factor of 10 % higher or so.
We found that a BS misalignment of 0.2–0.3 μrad in either pitch or yaw is sufficient to induce hopping of the SRC mode from TEM00 to TEM10/TEM01. We did this as follows:
Below are plots with the SRC sideband power vs BS misalignment. The "hopped" region corresponds to ~0.3 urad misalignment wrt to the "aligned" state. The power drop is about 30%. This is pretty similar to what has been observed before using the TCS to match the ITMs thermal lenses.