Spaceborne Multispectral Imager

The proposed program contains two innovations to improve the useability of acousto-optic tunable filters (AOTF's). The first is the use of a phased array for the acoustic transducer to achieve acoustic wavefront steering. This will permit real-time control of bandwidth. The technique can be applied to existing non-collinear AOTF's such as TeO2. The second innovation is the use of amorphous polymer materials instead of crystals as the acousto-optic medium. By inducing birefringence in the polymer, material optical properties can be changed in real time. Each of these innovations would provide the ability to control bandwidth based on the measuring conditions rather than have the bandwidth increase as the square of the wavelength as is presently the case in today's AOTF's and liquid crystal tunable filters. These innovations would make AOTF's useful for spectral imaging for Earth observation.