Translator Disclaimer
16 September 1992 Tunable solid state infrared filters for multispectral imaging
Author Affiliations +
This paper will review fundamental aspects of an innovative approach to multi-spectral imaging by exploiting variable electronic conductance properties of semi-conductor and semi- metal materials to create a tunable, bandpass infrared filter. The filter would operate through use of a controlled wavelength dependent change in optical reflectance that is a characteristics of electrochromic and photochromic materials. The reflectance effect is predicted by modified Drude free electron models for metallic-like conducting systems. As a design example, a filter based on doped tungsten trioxide (WO3), will be presented. Another filter design resulting in an all solid state device would use properly constructed and doped silicon or GaAs and operate at cryogenic temperatures. These filter designs use a Michelson interferometer configuration with different reflective structures in the two 'arms'. Wavelength control is provided through electric field induced changes to the electronic charge carrier concentrations found in a thin layer at the surface of the active mirror materials.
© (1992) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
David A. Swanson and Leo Laux "Tunable solid state infrared filters for multispectral imaging", Proc. SPIE 1690, Design of Optical Instruments, (16 September 1992);

Back to Top