Sensitivity enhancement of thermal infrared imagers with bimaterial cantilevers through piezoelectric actuation

Sensitivity enhancement of a thermal infrared imager with bimaterial cantilevers is demonstrated while being piezoelectrically actuated at its resonance frequency. The enhanced sensitivity is investigated by both theoretical analysis and experimental measurement of the vibration amplitude of the absorption mirror within a focal plane array, mounted on top of a piece of piezoelectric thin film and actuated at the resonance frequency of the thermal infrared imager. This work presents that the minimum detectable radiation power of an infrared photodiode is 0.02 mW with the infrared imager under vibration at its resonance frequency. However, the same radiation power, 0.02 mW or even a higher radiation power of the infrared photodiode cannot be detected without piezoelectric actuation with all the other experimental conditions unchanged. The proposed sensitivity enhancement approach is feasible for the infrared imagers with the output signals generated from their structural motion. (c) 2006 American Institute of Physics.