matthewrichard.todd@LIGO.ORG - posted 23:56, Wednesday 17 December 2025 (88585)
CHETA build log -- Wednesday 12/17
M. Todd, G. Vajente, L. Dartez
Wednesday 12/17
- Additional optics mounted
- ZnSe 2” lens
- 2” silver and gold flipper mirrors (not installed)
- Additional beam dump for reflection of Polarizer2
- We had the PD chassis milled out further to take an offset out that prevented the board from sitting flush.
- We noticed that the coating had been burned on the first beam sampler we got from EdmundOptics. Emailed vendor to ask if this is common, because the power density is not at all expected to have produced this.
- We also took beam profiles with a rail installed to get a fit of the beam evolution between M2 and M3. I made a fit of the data, assuming that M2 was perfect (I was having trouble with the nonlinear fit without M2=1, will revisit).
To do tomorrow:
- Try and compare the lens solution to the fitted q we have from measurements.
- Try and set up the coaligned visible laser
--- Horizontal (A1) Fit ---
Data range: z = [339.0, 897.8] mm
Beam radii: [1525.0, 2150.0] µm
Fixing M² = 1
Fit converged: w₀=1034.2 µm, z₀=-465.0 mm, M²=1.00 (fixed)
BeamFitResult(w0=1034.2±49.9 µm, z0=-465.0±33.9 mm, M²=1.00±0.00)
--- Vertical (A2) Fit ---
Data range: z = [339.0, 897.8] mm
Beam radii: [1138.5, 1825.2] µm
Fixing M² = 1
Fit converged: w₀=828.8 µm, z₀=-80.0 mm, M²=1.00 (fixed)
BeamFitResult(w0=828.8±32.5 µm, z0=-80.0±21.1 mm, M²=1.00±0.00)
Images attached to this report
