Evaluating the spectroradiometric performance of an uncooled midwave infrared hyperspectral interferometer using a microbolometer array detector

Improved technology and emerging interferometric techniques have allowed the use of uncooled microbolometers in the long-wave infrared (LWIR; 8 to 14 mu m) for hyperspectral imaging (HSI). The midwave infrared (MWIR; 3 to 5 mu m) presents several advantages with respect to the LWIR for Earth and planetary science. For example, important atmospheric trace gases on Earth such as CO2 and CH4 are not masked by other atmospheric constituents in the MWIR. However, HSI in the MWIR is more challenging at ambient Earth temperatures because less radiance is available to measure. We describe how hyperspectral images in the MWIR can be acquired with an instrument using an uncooled microbolometer married to a Sagnac interferometer. Standard characterization tests are used to benchmark the performance of the microbolometer instrument with a cryogenically cooled photon detector with the same optical design. At a spectral resolution of 100 cm(-1) (17 bands between 3 and 5 mu m), we measured a signal-to-noise ratio (SNR) of 100 at 30 degrees C with the microbolometer instrument and an SNR of 50 at 50 cm(-1) (33 bands). Results from this work show that coupling microbolometers with interferometers allows for quality measurements with adequate SNR for high-temperature science applications. (C) 2020 Society of Photo-Optical Instrumentation Engineers (SPIE)