Patent ID: 7116418

Claim:
A spectral imaging apparatus, comprising: a diffraction grating having an entrance slit formed therein, said entrance slit having a long dimension oriented in a y-direction, said entrance slit being adapted to transmit an incident radiation therethrough; a collecting reflecting element for receiving said incident radiation transmitted through said entrance slit and reflecting said incident radiation to a diffractive surface of said diffraction grating, a plurality of grooves on said diffractive surface being substantially parallel to said y-direction, said collecting reflecting element including an aspherically-shaped portion; and a reimaging system adapted to receive radiation diffracted by said diffractive surface and to provide a spectral image at a focal surface, wherein said spectral image being further adapted to provide a spectrum of radiation from the incident radiation propagating through said entrance slit such that a first portion of the spectrum of radiation from a first region in the y-direction can be distinguished from a second portion of the spectrum of radiation from a second region in the y-direction.