This is nice. Can we test this idea with POP22 + a razor blade?

Just to take transfer functions in PRMIsb between the PRM angle to POP QPD/POP22+razor blade
as well as the noise spectrum measurement are already useful.

We want to figure out the requirement for the 2f QPD.
(Transimpedance / Noise level / Beam size / etc)

Depending on the requirement we'll see if we need demodulation or just a power detector.