The EUCLID-style Michelson readout is on the SP table now and is aligned. See image below. I took several power spectra with the plotter attached to the HP3563 (not sure if there's another way to get the data out) and I'm still waiting to calibrate (since dP/dL isn't constant as it isn't locked, this is taking a bit longer). When put into XY mode on the oscilliscope (plotting Voltage at PD2 on the x and Voltage at PD3 on the y), a Lissajous figure as in the first plot below. It's offset and elliptical due to imperfections (noise, dc offset, etc) but can ideally be used to calculate the L_ target mirror movement. By rotating the first quarter wave plate by ~80.5deg counter-clockwise (fast axis was originally at Pi/8, now at 103deg), I was able to turn the Lissajous figure from an ellipse into a more circular shape, which would ideally allow for us to use a circular approximation (much simpler) in our displacement calculations. |