Wavelength and Polarization Agile Infrared Detectors based on HgCdTe

Modern seekers need to detect, recognize, identify and track a variety of autonomously guided munitions under a wide spectrum of conditions and countermeasures. We propose the implementation of hyperspectral and polarization-sensitive techniques based on HgCdTe infrared detectors to improve the accuracy of target detection for these seekers. In the proposed hyperspectral system, the HgCdTe detector senses only infrared photons of a particular wavelength selected by a tunable Fabry-Perot interferometric filter. The Fabry-Perot structure consists of a pair of vertically distributed Bragg mirrors and a membrane, with an air gap, the thickness of which determines the narrow wavelength band of infrared radiation that passes through to the detector. The filter tunability is achieved by applying a bias voltage across the two distributed Bragg mirrors. Polarization detection capabilities will be added to the hyperspectral elements by overlaying an array of microgrid polarizers. We will extract the Stokes parameters and obtain polarization images. The proposed technique will operate at high frame rates with minimum distortion, will be lightweight and compact. EPIR Technologies is the only small company with the facilities and demonstrated expertise for the molecular beam epitaxial growth of high-quality HgCdTe-based materials and its processing into high performance detectors.