H-PDLC Tunable Filter for Hyperspectral Imaging

Weapons of Mass Destruction (WMD) are a threat to society and national security. Hyperspectral Imaging (HSI) provides a means for detecting WMD. A core element of a HSI system is a tunable wavelength filter. There is a need for faster tunable wavelength filters than those that currently exist in practice. The Phase I effort addressed this shortfall by developing and demonstrating a tunable wavelength filter based on a Holgraphically formed-Polymer Dispersed Liquid Crystal (H-PDLC). These devices consist of a polymer and micron sized LC droplets composite, resulting in improved electro-optical properties compared to traditional LC materials. Advantages include faster switching times, wide wavelength operating range across the ultraviolet to infrared, narrow wavelength resolution, and high transmission. In the Phase II effort, development will continue to increase filter clear aperture to greater than 2 inches, increase reflection efficiency to greater than 70%, achieve single wavelength operation over 90 degree full field acceptance angles, and faster switching speed and lower switching voltage. The Phase II effort will culminate with fabrication and testing of a single-substrate H-PDLC tunable filter that operates across 400-800 nm and provides 10 nm wavelength resolution. Commercial Applications and other Benefits as described by the awardee: A HSI network of multiple sensors can be used simultaneously to monitor a given location and acquire spectral content that uniquely provides information on materials. The collected spectral information can be analyzed through the use of libraries and databases to identify materials characterizing potential threats. This information can then be sent on to government and military security officials in order initiate a suitable response. Within the private sector HSIs may be widely adopted for natural resource assessment and management, particularly in the areas of agriculture and sylvaculture.