Methods to achieve wavelength selectivity in infrared microbolometers
A simple Salisbury Screen structure has been adopted for conventional infrared microbolometer, which is usually designed to detect only one infrared band. Dielectric coated Salisbury Screen modified from the Salisbury Screen successfully shows narrow wavelength band absorption in a given wavelength range that is required for hyperspectral imaging. An approach for designing simple Salisbury Screen for broad band and Dielectric coated Salisbury Screen for wavelength selectivity is presented. Calculations of electromagnetic behaviors of designs and verification are presented. Additionally, Dielectric coated Salisbury screen without air gap and simple Salisbury Screen with dielectric spacer layer are fabricated, and the spectral response of those devices are measured. Comparison between simulated and measured data of these devices are presented and discussed. Finally, the narrow wavelength band absorption of the patterned resistive sheets in LWIR is presented for future work.