Volume Holographic Gratings for Improved Beam Splitting in Multi-Spectral Passive Anti-Submarine Warfare System

RL Associates, Inc. proposes to design, construct, and test a 12-channel multi-spectral beamsplitter using volume holographic optical elements for use in the Navy’s electro-optic passive antisubmarine warfare system (EPAS). EPAS currently uses 12 spectral filters, one per visible channel, each having separate lenses for collection of visible spectra. These distinct optics and optical mounts for each channel result in a large and unnecessarily complex system. By optimizing beamsplitting using a single volume holographic element with spatially or volumetrically multiplexed gratings, the size and weight of collection optics can be greatly reduced. The advantage of using holographic gratings to optimize beamsplitting lies in the ability to tailor the bandpass, diffraction angle, and output beam characteristics to the specific system. The ability to multiplex several gratings in one substrate is an added advantage when looking for a multi-spectral beamsplitting solution. We propose to continue design and testing of a 12-channel optical beamsplitter composed of a series of multiplexed volume holographic gratings which can be tailored to the desired acceptance angle and spectral range of a particular multi-spectral system.