Blue-Green Filter Technology.
Abstract
New concepts in wide field-of-view (approx. f/0.5), very narrow band (approx. 0.1 A) optical filters in the blue-green spectral region are sought for submarine receivers in the Navy OPSATCOM laser communication link. This program was an attempt to extend the current state of the art by exploring novel techniques that would lead to improved, useful receiver filters. Of the six general approaches investigated, two were considered principal candidates: the electrooptic iso-index coupled-wave filter, and nearly degenerate four-wave mixing. It was shown that a coupled-wave electrooptic filter exhibits a theoretical 2pi field of view (FOV) and a passband of 0.2 A at 4970 A using a 1-cm sample of AgGaS2. Tunability above and below the resonant wavelength was also shown to be feasible. The four-wave mixing approach also has a 2pi FOV and, with adequate pump power, can exhibit gain. Very narrow optical bandwidths (approx. 0.08 A) and maximum skirt rejection were demonstrated theoretically. The latter approach has the biggest potential payoff but the highest risk, while the coupled-wave EO technique is basically very simple, limited only by materials availability. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1979
- Accession Number
- ADA067789
Entities
People
- D. M. Henderson
- J. F. Lotspeich
Organizations
- HRL Laboratories