Abstract: A high resolution aberration corrected concentric spectrometer (10) includes a convex diffraction grating (60) having a plurality of nonparallel lines. The curved lines of the convex grating (60) provide correction for field aberrations. The utilization of a convex diffraction grating (60) enables the present spectrometer (10) to provide highly accurate spectral imaging with greatly improved resolution. By utilizing the convex diffraction grating (60) with the nonparallel grooves, the spectrometer is functional for a large number of applications.

Abstract: A spectral analysis system which may operate as a spectrograph or monochromator comprises a folded optical path within a housing wherein the optical input is provided on one side and the optical output is provided on an opposite side at a spectral focal field, thereby separating optical and electrical functions. The folded optical path is provided within a vertically extending portion of the housing providing for a narrow profile to the optical instrument and keeping the entrance and exit apertures in-line in close proximity. The grating is caused to operate in a near Littrow condition with a reflecting prism having first and second inclined surfaces which respectively reflect entrance aperture light to said grating and disperse exit aperture light from said grating along paths slightly inclined to the Littrow axis of the grating.