Wide Field of View Narrowband Holographic Grating Array for Improved Spectral Filtering in High Altitude Antisubmarine Warfare Systems

RL Associates, Inc. proposes to design, construct, and test a narrowband, wide field of view, volume holographic optical element (VHOE) array for use as a filter in high altitude antisubmarine warfare (ASW) Light Detection and Ranging (LIDAR) systems. High altitude LIDAR systems are currently limited by available spectral filter technology. These systems, which utilize an interrogation source of a visible wavelength, have poor signal to noise ratios when operated in the daylight, due to scattered returns from sunlight off the water’s surface. Narrowband spectral filters are used to improve daytime performance by blocking returned signals outside the spectral band of the interrogation source. However, many narrowband filters have the added disadvantage of restricting the system field of view. We propose to develop a new type of spectral filter composed of an array of volume holographic gratings which can be tailored to a broad acceptance angle while maintaining an extremely narrow spectral bandpass of 1 Å or less. We also propose to study volume holograms for use as beam splitters in multispectral systems.