Transient response characteristics of position sensitive detector irradiated by moving light source

摘要

A distributed RC transmission-line approximation is used to analyze the transient response characteristic of one-dimensional (1D) position sensitive detectors (PSDs). A generalized mathematical model has been developed for a moving light source illuminated on the PSD. The relative error curve has been given between the computed and true incident positions of light under different moving speeds, and the impact of different starting positions has been analyzed on the position detection error of light. It is shown that when the moving speed is less than the tenth characteristic speed, the output photocurrents can be rather linearly detected as long as the measuring time is longer than the delayed time maximum. It is also found that the distance between the original point and starting position should be as short as possible in order to obtain the correct incident position of light. The computed photocurrents have been compared with data simulated using the ANSYS software, and qualitative agreement is found.