Abstract: Spectra corresponding to overlapping grating orders are focused onto a multi-waveband focal plane array in order to create spectral images of a scene simultaneously in multiple wavelength regions. The blaze of the grating is chosen so that all spectral orders are dispersed with high grating efficiency. Such an approach extends the spectral range of disperse spectrometers to several octaves of wavelength, while preserving the compact packaging and cryogenic requirements of conventional (one octave) instruments.

Abstract: A multi-band pupil stop is disclosed for use in multi-band focal plane array imaging systems. The object is to provide similar point spread functions at the focal plane array. The pupil stop is comprised of one or more nested annuli. Each annulus is a pass-band filter with the outermost annulus passing the longest wavelength waveband and each successive inner annulus passing a successively shorter wavelength waveband. The pass-band of each annulus is such that the ratio of the center wavelength of each pass-band to the outer diameter of each annulus is approximately equal.