Abstract: A concentric spectrometer which reduces stray light and re-entrant spectra within the spectrometer. The spectrometer includes a non-direct optical path between the entrance slit assembly and exit aperture. Dyson and Offner concentric optical configurations are used to eliminate third-order aberrations The concentric optical system includes a light trap which mitigates or eliminate stray light due to reflection of light incident on the exit aperture region but which does not impinge on the active area of a detector optically coupled to the exit aperture. A two-dimensional area array detector concurrently senses a spectral signal corresponding to an input optical radiation signal and a signal corresponding to zero-input radiation, and the spectral signal is corrected according to the zero-input radiation signal.
Type:
Grant
Filed:
March 12, 1998
Date of Patent:
January 30, 2001
Assignee:
Gretag Macbeth LLC
Inventors:
Perry A. Palumbo, William L. Weber, Harold R. Van Aken, Robert K. McMahan