SBIR Phase II: Hydrothermal Growth of Potassium Beryllium Fluoroborate (KBBF) for deep UV Nonlinear Optical Applications.

This Small Business Innovation Research (SBIR) Phase II project will develop a commercial growth process for single crystals of KBe2BO3F2 (KBBF) using hydrothermal techniques. The compound was developed 10 years ago and shows exceptional promise as a deep UV non-linear optical (NLO) material. The sub-200 nm region is presently inaccessible for solid-state lasers, and optical components functioning at these wavelengths are limited. KBBF has excellent deep UV properties and shows great promise for laser applications like frequency doubling and wavelength mixing. A previous flux growth method for the crystals demonstrated excellent performance in deep UV lasing, but the material is very difficult to grow in the required single crystal form. Additionally, China has embargoed crystals grown by this method, as well as the process, so KBBF crystals are currently unavailable outside of China. The broader impact/commercial potential of this project will be to continue to develop the hydrothermal method for growth of single crystals for optical applications. NLO materials are vital for the development of solid-state lasers with wavelengths below 200 nm for use in photolithography, micromachining and spectroscopy. The availability of KBBF crystals will also enable new technologies, such as standoff explosive detection. This technology will help the rebirth of the advanced materials industry in the United States. The crystal growth industry has moved nearly completely offshore, leaving the United States vulnerable in terms of advanced applications, with a shrinking pipeline of new strategic materials, especially in the field of optics. This field is particularly dependent on new materials and the US is in serious danger of losing our once-substantial competitive edge. Additionally, a postdoctoral student will be supported through a subaward to Clemson University, and will become part of the next generation of materials scientists and engineers in this country.