The Perkin-elmer Corporation

Robert Crane, Jr

Paul R Yoder

Eugene R Schlesinger

David S Dunavan

An imaging coherent radiometer incorporating a Fabry-Perot interferometer which is scanned or nutated, for detecting and determining location and wavelength of coherent radiation or the coherent absence of radiation in the presence of non-coherent ambient radiation.

Fabry-Perot scanning and nutating imaging coherent radiometer

An imaging coherent radiometer for detecting and determining the location and wavelength of coherent radiation or coherent lack of radiation in the presence of non-coherent ambient radiation. The apparatus includes an unequal path interferometer which divides incoming radiation containing coherent and non-coherent radiation into a first beam path and a second beam path through which a first beam and a second beam, respectively, travel. The optical path length difference between the first beam path and the second beam path are greater than the coherence length of the non-coherent radiation, but substantially less than the coherence length of the coherent radiation or coherent lack of radiation. Modulation means are provided to cause a predetermined difference in the optical frequencies between the first beam and the second beam proportional to a modulation signal. The first and second beams are then recombined into a recombined beam. Detecting means are provided to detect the interference of the first and second beams across the entire wavefront of the recombined beam, and over the entire image of the scene being viewed. Processing means detect and determine the location and wavelength of coherent radiation or coherent lack of radiation in the scene being viewed by the apparatus. This information can then be visually displayed. Additional processing means to respond to specific coherent wavelengths or wavelength sets.

Imaging coherent radiometer

A passive compensating device which compensates for angular and translational misalignment errors in a polarized beam and assures the projected beam centroid remains at the same position. The device splits the incoming beam into two beams. Thereafter, optical orienting means disposed to intercept the two beams is operative to rotate the wavefront of both beams so that the composite beam exiting a combiner has two components wherein one component has its wavefront rotated 180.degree. about two orthogonal axes with respect to the other beam. Accordingly, the composite beam centroid is maintained at one position regardless of jitter of the beam entering the compensator device.

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Westport, CT, United States of America

Robert Crane, Jr