Ryan S, Camilla, Sheila
We put a temporary steering mirror into HAM7, upstream of ZM4 sending the beam out to SQZT7 to try to measure the M^2 and beam astigmatism before ZM4. Location of mirror attached. Repeated with different ZM2 PSAMs values.
- Steering mirror to BM3 = 635mm
- Steering mirror to ZM4 = 450mm
- Steering mirror to Beam Diverter = 235mm
The M^2 data is attached but seemed debatable, with high with M^2 values: > 1.5 when we expect <1.2 to align with 90783. Maybe as the beam was large at the Thorlabs M^2 head, but it was smaller than specs, ~5mm diameter when max was 9mm diameter.
This morning Ryan and I moved the steering mirror to downstream of ZM4 and repeated these measurements, with different ZM4 PSAMs values and then with ZM4 PSAMs back to nominal and a few different ZM2 PSAMS settings. Data attached.
Yesterday we moved the flipper mirror picking off the beam into the M^2 2" off the nominal path, today we moved it back to be in the nominal Homodyne/IR PD path.
- Steering mirror to ZM4 = 395mm
- Steering mirror to beam diverter = 150mm