Claims
- 1. A method of protecting a sensitive photodetector from high-intensity, multiple-wavelength, coherent input radiation present in a non-coherent input radiation spectrum through the use of a photorefractive crystal, including the steps of:
- cutting the photorefractive crystal such that the surfaces of incidence and exit are parallel to each other and to the direction of the largest electro-optic coefficient, normally referred to as the C axis of the crystal;
- orienting said photorefractive crystal such that input radiation entering the crystal does so at an angle falling within a predetermined range as determined by the angular range of the specific crystal material selected over which enhanced beam fanning occurs for multi-wavelength coherent radiation, known as rainbow scattering, with said angle being measured between a plane perpendicular to the C axis of the crystal and the angle of incidence of the input radiation;
- focusing said input radiation onto the face of said crystal whereby the angle of incidence of the input radiation within the predetermined angular rainbow scattering range of the crystal, where enhanced beam fanning occurs.
Government Interests
The invention described herein may be manufactured, used, and licensed by the U.S. Government for governmental purposes without the payment of any royalties thereon.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4772785 |
Cheng et al. |
Sep 1988 |
|
4877297 |
Yeh |
Oct 1989 |
|