Development of a High-Efficiency Ultra-Narrowband Volume Holographic Optical Filter

The overall objective of this project is to design, build, and test a prototype optical filter with the following characterisitcs; Operating Wavelength - 530.286 nm and 630.25nm, Filter Linewidth - 0.05 nm at 530 nm and 0.016 nm at 630 nm, TuningSensitivity - 2.96 degrees / nm, Tuning Range > 2 nm, Efficiency: > 75%, Aperture - 40 mm, Angular Acceptance - 0.5 degrees. We have demonstrated in the Phase I effort that the optimal choice of a filter optical element is a thick volume holographicdiffraction grating written into MEMPLEXr, a photopolymeric material. Numerous systems currently under development by all departments within the DOD involve detection of weak optical signals in the presence of significant unwanted background noise suchas solar radiation. These systems are being applied in arenas such as astronomical observation, which utilizes passive systems to detect plasma emissions, and active systems for observing specific excitations, as in gravity wave detection of sodium lines.Another area of application is light detection and ranging (LIDAR) which is used to detect everything from cloud formations and airborne objects to underwater objects such as mines and submarines. The signal-to-noise ratio in these systems is directlyproportional to the transmission of a bandpass optical filter and inversely proportional to the filter linewidth. A narrow linewidth, high efficiency optical filter would greatly enhance the performance of all types of these systems.