Optical system and method for eliminating overlap of diffraction spectra
AssigneeLitton Systems, Inc.
InventorsBruce A. Horwitz, Steven J. Wein
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Abstract
An optical system and a method for separating overlapping spectra from a diffraction grating and an imaging spectrometer with increased free spectral range are disclosed. The light from a diffraction grating consists of multiple spectra overlapping each other and displaced along a spectral axis. The invention directs the light from the grating to a refractive element such, as a prism. The prism further disperses the light along the same spectral axis. The individual spectra are sufficiently displaced such that they no longer interfere with each other.
Claims23
A method of separating spatially overlapping diffraction spectra comprising:
- diffracting light from a scene to produce a first plurality of spectra, said first plurality of spectra being spatially distributed along a spectral axis and spatially overlapping along the spectral axis;
- and
- directing the light of the first plurality of spectra through a dispersive element, said dispersive element spectrally dispersing the light of the first plurality of spectra along the spectral axis to produce a second plurality of spectra, said second plurality of spectra spatially overlapping along the spectral axis less than the first plurality of spectra.
An optical system for separating overlapping diffraction spectra comprising:
- an apparatus for diffracting incoming light from a scene into a first plurality of spectra, said first plurality of spectra being spatially distributed along a spectral axis and spatially overlapping along the spectral axis;
- and
- a dispersive element for spectrally dispersing the light of the first plurality of spectra along the spectral axis to produce a second plurality of spectra, said second plurality of spectra spatially overlapping along the spectral axis less than the first plurality of spectra.
An imaging spectrometer comprising:
- an aperture for passing light from a scene;
- a diffraction grating for producing a first plurality of spectra, said first plurality of spectra being spatially distributed along a spectral axis and spatially overlapping along the spectral axis;
- and
- a refractive element for spectrally dispersing the light of the first plurality of spectra along the spectral axis to produce a second plurality of spectra, said second plurality of spectra overlapping along the spectral axis less than the first plurality of spectra.
Dependencies are inferred from the claim text.