Theoretical analyses for the relationship between the performance of quadrant photodetector and the size of incident light spot

Quadrant photodetector is one of the most popular detection devices for tip/tilt sensing. The measurement range and detection sensitivity, depending on the size of light spot incident on the quadrant photodetector, are theoretically analyzed and discussed in the application cases of the uniform irradiance distribution and of Gaussian irradiance distribution of the incident light spot. According to the theoretical results, the larger the size of the light spot is, the greater the measurement range of the quadrant photodetector, and the smaller the detection sensitivity of the quadrant photodetector.