Patent ID: 7265827

Claim:
A device for separating light into its components providing a light output in a selected spectral band from a sample light input into the device for separating light into its components, comprising: (a) an input light source having a wavelength component or components; (b) a first concave spectrographic diffraction grating, said first concave grating defining first optical grooves and being positioned to receive light from said input light source, said first grooves being oriented in a first direction and said first grooves being configured to provide once diffracted light, dispersing said components of said input light source in a first dispersive direction, said dispersing forming said input light into an intermediate spectrum, said intermediate spectrum being formed on a focal surface by said once diffracted light; (c) a slit substantially positioned on said focal surface or approximately on said focal surface, 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, said second concave diffraction grating defining second optical grooves positioned to receive once diffracted light from said slit, said second grooves being oriented in a second direction and said second grooves being configured to provide a twice diffracted light, said second concave diffraction grating dispersing the components of said once diffracted light in a second dispersive direction, said second dispersive direction extending across said first dispersive direction, said dispersion forming said input light into an output spectra, said output spectra being formed on a focal surface by said twice diffracted light.