Impact of Standard Deviation and Reflectance of the Measured Surface on Laser Diode-Position Sensitive Detector System

For improving the accuracy and applicability of laser diode-position sensitive detector (LD-PSD) system, a model of roughness and reflectance of the measured surface is established. Combining this model with the light intensity response model of PSD and the space radiation model, we derived the relationship between the standard deviation (σ), reflectance (ρ) and the center-of-gravity of light intensity (Χ0). This relationship shows that Χ0 is disturbed by σ or ρ only if σ or ρ changes within the spot. We conducted a simulation and experiment to test this relationship. The results showed a good consistency with the theory, which proved that the variation of σ and ρ can greatly impact the accuracy and robustness of LD-PSD system, and a smaller light spot can improve this situation.