Patent ID: 6952260

Claim:
A device for separating light into its components providing a light output in a spectral band from sample light input into the device, comprising: (a) an input light source; (b) a first concave spectrographic diffraction grating positioned to receive light from said input light source and configured to provide a once diffracted light output dispersing the components of said input light source, said dispersing forming said input light into an intermediate spectra, said intermediate spectra being formed in a focal volume by said once diffracted light; (c) a slit substantially positioned in said focal volume or approximately in said focal volume, said slit having a first edge whose position corresponds to the shortest wavelength for light to be passed by said slit and having a second edge whose position corresponds to the longest wavelength for light to be passed by said slit; and (d) a second concave diffraction grating positioned to receive said once diffracted light from said slit and configured to provide an image on a focal surface in the form of a twice diffracted light output, said first concave spectrographic diffraction grating being oriented to disperse the components in a first direction on said focal surface as a function of wavelength, said second concave diffraction grating dispersing the components of said once diffracted light in a second direction on said focal surface, said second direction on said focal surface being different from said first direction on said focal surface, said dispersion forming said input light into an output spectra, said output spectra being formed on said focal surface by said twice diffracted light, said output spectra having an orientation which is oblique with respect to said first and second directions.