Wide-angle narrow-bandpass optical detection system optimally designed to have a large signal-to-noise ratio

A method for achieving optimal design of a wide-angle narrow-bandpass optic al detection system composed of a spherical interference filter and a circu lar photodetector is introduced. It was found that there is an optimal phot odetector diameter that maximizes the signal-to-noise ratio (SNR) for a giv en filter configuration. We show how to optimize optical detection systems based on spherical interference filters for all the important parameters si multaneously. The SNR values of these systems are compared with the SNR val ues of spherical-step-filter-based detection systems. When large silicon ph otodetectors are used, the two systems have equal SNR values so that the mo re economical step-filter systems are preferable. The results given here in the near-infrared region can be used for the optimization of any configura tion of a detection system based on a spherical interference filter and a s ilicon photodetector working at the same wavelength range, without further calculations. (C) 2000 Optical Society of America.