Excited State-Atomic Optical Filters at 532 nm

RL Associated proposes to develop two types of extremely narrow linewidth optical filters at 532 mm which could greatly enhance all light detection and ranging systems which use doubles Nd: YAG as their transmitter. These systems include; airborne remote sensing of ocean water temperature and salinity, airborne underwater target detection and imaging, airborne ocean water environmental sensing and space based satellite communications. Both filters are based upon polarization rotation in atomic vapors caused by a transition between two excite-states. These filters offer extremely narrow linewidth because they are based on atomic transitions and are easily "gateable" by quickly switching the optical pump responsible for the excited-state population. Both filters have the following characteristics: center wavelength 532.33, linewidth 20, transition > 5%, aperture > 1". The main goal of this proposed phase I effort is to study the feasibility of building these filters to integrate into currently existing systems. A prototype design will also be done for incorporation into a subsequent phase II effort. An optional task allows for the experimental measurement of the filters¿ performance.