Miniature Spherical Retroreflectors Fabricated by Fluidized Bed CVD

As part of the DOE Proliferation Detection Program, miniature spherical lenses are sought for remote chemical detection using LIDAR. These miniature lenses can serve as retroreflectors for the atmospheric detection of chemical threat agents. Currently, there is no reliable method for producing these spherical lenses, which require a graded index profile of at least 0.2 over their entire radius, at a size in the few mm. This project will develop miniature spherical lenses with controlled refractive index profile using fluidized bed chemical vapor deposition (FBCVD). Phase I will demonstrate proof-of-concept by fabricating millimeter-sized, silica-based glass spheres with a defined and controllable index profile, and characterize their optical properties and quality. Phase II will expand the technology to include other material compositions, including chalcogenide glasses, to extend the transmission wavelength, tune index profiles, refine optical quality, and scale up for economical Phase III production. Commercial Applications and other Benefits as described by the awardee: The graded index retroreflector spheres would improve national security by enhancing the capability of remote chemical sensing. These retroreflector spheres also could find use in other applications of remote chemical sensing, including the monitoring of automobile exhaust, chemical and power plant effluent, and others.