This is my paper on comparing RF Jitter Alignment Sensing (RFJAS) to the traditional WaveFront Sensing (WFS)
alignment schemes together. WFS is currently being used at LIGO, and we explore the limits of it.
Our study shows that WFS is limited by beam spot motion (BSM) nosie on the QPDs. This is the noise
that comes from the need to have the beam centered between all quadrants of the QPDs. More details
about it can be found in the paper. Animation of BSM can be found in Animations tab
BSM
- RFJAS (PDF)