Resolution limit of the quadrant photodetector

A theoretical analysis of the resolution limit of the light spot position measurement with the quadrant photodetectors has been presented in this paper. In order to reduce the interquadrant crosstalk each quadrant is separated from the adjacent quadrants with a narrow light-insensitive gap. However, it was found that these gaps limit the measurement resolution. Nevertheless, the estimated resolution is still just an order of magnitude lower than the resolution in position measurement with the standard quantum limited interferometer based on the He-Ne laser.