Progress on characterization of a dualband IR imaging spectrometer

A dualband infrared focal plane array is the central component of a compact, low mass, multispectral imaging spectrometer with perfect spectral registration. The prototype spectrometer design uses a grating blaze chosen to be efficient over both 3.75-6.05 and 7.5-12.1 µm, although the mercury cadmium telluride focal plane array limits the bandwidths with cutoff wavelengths near 5.2 and 10.5 µm. The spectrometer has been spectrally calibrated with flooded blackbody illumination and offset and gain corrections have been performed. The wavelength resolution is ±0.024 µm in the MWIR and ±0.083 µm in the LWIR, however this limitation is caused by the calibration method and not by the design. The potential for determining the temperature of a blackbody or greybody from the ratio of two narrow wavebands has been demonstrated