Optical position detection for MOEMS scanner mirrors with arbitrary trajectories

For electrostatically driven MOEMS devices, which do not have intrinsic on-chip feedback, position information can be provided by optical methods, most simply by using a reflection from the backside of a MOEMS scanner. One possibility, which is applicable to arbitrary trajectories, is based on the measurement of the position of the back-reflected light with a quadrant diode. In this work, we present results from tests with a quadrant diode with a central hole, which provides robust results and enables a very compact design.