An active method to improve the measurement accuracy of four-quadrant detector

Abstract

Improving measurement accuracy over a wide range is very important for the measurement system based on four-quadrant detector (4QD). However, its measurement performance is easily affected by the energy distribution of the spot imaged on 4QD, which limits its wider practical application. Existing methods mainly use the collected data for curve fitting to improve the measurement accuracy. However, actual data collection may be difficult, and the spot energy distribution imaged on 4QD may change at any time. In this paper, an active method to improve the measurement accuracy of 4QD is proposed, which can adapt to the change of the spot energy distribution without additional actual data. Experimental results show that the proposed method can effectively improve the measurement accuracy over a wide range with fast detection speed.