A COMPARISON OF THE LIMITS TO THE PERFORMANCE OF THERMAL AND PHOTON DETECTOR IMAGING ARRAYS

Photon detectors are fundamentally limited by generation-recombination noise arising from photon exchange with a radiating background. Thermal detectors are fundamentally limited by temperature fluctuation noise arising from radiant power exchange with a radiating background. These two classes of detectors have differing dependencies of their detectivities upon their operating temperature and that of the radiating background. The limits favor photon detectors at shorter wavelengths (LWIR) and lower operating temperatures. Thermal detectors are favored at longer wavelengths (VLWIR) and higher operating temperatures.