The effect of spot size on linearity improvement of tetra-lateral position sensitive detector

Linearity improvement of tetra-lateral position sensitive detector (PSD) is highly desired in many applications where accurate measurements of the PSD are required. The effect of beam size on our newly proposed linearity improvement scheme is discussed in this paper. Theoretical studies on the electrical potential and collected photocurrents are presented to simplify the numerical calculation when the beam size of the spot is considered. Simulation results show that our new formula can still give a nearly perfect linearity and measurement accuracy even if the spot has a considerable beam size.