Improving measurement accuracy of Position Sensitive Detector (PSD) for a new scanning PSD microscopy system

摘要

Measurement accuracy of Position Sensitive Detector (PSD) can be greatly affected by inaccuracies in interface circuits, system connections, outside environmental changes and the semi-conductive properties of the sensor. The presence of these factors causes noises and distortions that heavily degrade the performance of the PSD and any system built on it. This work addresses improving measurement accuracy of the PSD by using various correcting methods and filters to eliminate signal noises throughout the system and also develops a distortion rectifying methodology to rectify pincushion-type radial distortion associated with the PSD devices, which would enhance measurement accuracy in a larger active area of the PSD. Experimental validation demonstrates the effectiveness of these accuracy improvement methods. The improved PSD system can be further used for a proposed scanning PSD microscopy system. The system is capable of scanning an object in scale of a few micrometers for rapidly measuring the dimensions of the object based on the vanishing effect and the multi-channel photo-current feedback mechanism. Preliminary results show the measurement performance of the proposed microscopy.