P. R. SCHUSTER ET AL. APPLIED RESEARCH Development of Optical Filters Based on Photorefract.pdf

P. R. SCHUSTER ET AL. APPLIED RESEARCH Development of Optical Filters Based on Photorefractive Materials Paul R. Schuster, Joseph A. Miragliotta, Michael E. Thomas, and David M. Rust hotorefractive optical filters meet many of the very stringent requirements of P modern electro-optic systems. They provide a narrow passband and good throughput. However, difficulties arise when designing a filter to operate at wavelengths where the photorefractive material has low sensitivity. We have demonstrated initial success in overcoming the frequency dependence. This task was accomplished by using an optical configuration of high sensitivity in terms of wavelength, incident angle, and polarization to generate prespecified grating spacings. The grating spacings were designed to satisfy Bragg conditions for efficient operation of the filter (diffraction efficiency) even when using lower sensitivity wavelengths and alternative geometries of interest. INTRODUCTION High-speed electro-optic systems with narrowband can be constructed from measurements of the polariza- spectral resolution and tunability are of interest for tion in spectral lines that are sensitive to the Zeeman optical filtering within a variety of applications. Global effect.1 These maps can be used to develop techniques climate change and airborne pollution have created a to forecast solar activity and its effects on communi- need for spectral imaging devices with sufficient sen- cations and satellite orbits. Also, as discussed by sitivity and wavelength resolution to measure minute Kunches et al.,2