Abstract

Imaging spectrometers have been used extensively in the NASA community. The data acquired are especially useful where both spatial and spectral information is necessary for object identification (e.g., mineral recognition and rocket plumeanalysis). Unlike current imaging spectrometers, acousto-optic tunable filters (AOTFs) have the capability of acquiring two-dimensional images at a narrow spectral band. In addition, the spectral band can be randomly selected by changing the rf frequency that drives the AOTF. These two characteristics and the lack of moving part make AOTF technology excellent for mineral analysis and geological mapping in future planetary missions. In this paper, we present the results of an AOTF imaging spectrometer that is currently being developed at the Jet Propulsion Laboratory. The spectrometer uses a tellurium dioxide acousto-optic cell and operates in the visible band (0.5–0.8 µm). The system has a spectral bandwidth of 4 nm and a field of view of 5°. Experimental results showing spectral imaging and measurements of rock samples will be presented. An AOTF spectrometer system using a fiber-optic bundle in the fore-optics and preliminary results of a near-infrared (0.8–2.5 µm) spectrometer will also be described.

© 1990 Optical Society of America