Patent ID: 8379203

Claim:
An optical system, comprising: an entrance for receiving a radiation from a source object; a first transmissive aberration corrector in optical communication with the entrance; an aberration-corrected concave diffraction grating in optical communication with the first transmissive aberration corrector, wherein the aberration-corrected concave diffraction grating includes a plurality of grooves that are non-parallel and unequally-spaced; a second transmissive aberration corrector in optical communication with aberration-corrected concave diffraction grating; and an image plane in optical communication with the second transmissive aberration corrector for recording a spectral image of the entrance slit, wherein the radiation of the source object is refracted through the first transmissive aberration corrector, projected onto and diffracted from the aberration-corrected concave diffraction grating, refracted through the second transmissive aberration corrector before projected on to the image plane to form the spectral image.