Compact optical wavelength discriminator radiometer

Abstract

A wavelength discriminator designed to collect broadband, multiple wavelength input energy, to isolate specific narrow bands of interest, and to image such narrow bands of interest upon closely spaced, separate detectors. This discriminator comprises optical devices (22, 18) for directing incoming radiant energy of a certain quality and involving a wide range of wavelengths through first (26a) and second (26b) wavelength selective reflectors separated by a medium that transmits the wavelengths of interest. The wavelength selective reflectors in accordance with this invention are in a non-parallel configuration and disposed in a double pass geometrical arrangement wherein energy of a certain wavelength reflected from the second wavelength selective reflector (26b) passes back through the first wavelength selective reflector (26a), with the energy from the first and second wavelength reflectors thereafter being directed onto respective detectors (32aand 32b). An embodiment involving a third wavelength selective reflector (26c) grouped with the first and second reflectors may be utilized, wherein energy of a different wavelength reflected from the third wavelength selective reflector passes back through both the second and first wavelength selective reflectors, with the selected wavelengths thereafter falling upon three separate detectors (32a, 32band 32c) of the array.