Spectral imaging apparatus and methods

A spectral imaging apparatus, comprising:

• a diffraction grating having a plurality of entrance apertures formed therein, said entrance apertures being distributed along an axis having a long dimension oriented in a y-direction, said entrance apertures being adapted to transmit an incident radiation therethrough;
• a collecting reflecting element for receiving said incident radiation transmitted through said entrance apertures 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;
• 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 apertures 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.

A method for spectral imaging, comprising:

• transmitting incident radiation through an entrance slit formed in a diffraction grating, said entrance slit having a long dimension oriented in a y-direction;
• receiving said transmitted radiation via a collecting reflecting element including an aspherically-shaped portion and reflecting said transmitted radiation to a diffractive surface of said diffraction grating, grooves on said diffractive surface being substantially parallel to said y-direction;
• and
• receiving radiation diffracted by said diffractive surface and producing a spectral image of said incident radiation transmitted through said entrance slit at a focal surface, wherein said spectral image provides a spectrum of 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.

A method for spectral imaging, comprising:

• transmitting incident radiation through a plurality of entrance apertures formed in a diffraction grating and distributed along an axis having a long dimension oriented in a y-direction;
• receiving said transmitted radiation via a collecting reflecting element and reflecting said transmitted radiation to a diffractive surface of said diffraction grating, grooves on said diffractive surface being substantially parallel to said y-direction;
• and
• receiving radiation diffracted by said diffractive surface and producing a spectral image of said incident radiation transmitted through said entrance apertures at a focal surface, wherein said spectral image provides a spectrum of radiation propagating through said entrance apertures 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.