Description: Deep-ultraviolet (UV) Raman spectroscopy is a powerful method to collect chemically specific information about complex samples because deep-UV (?? < 250 nm) excitation shows an over 200-fold greater efficiency compared to commonly used 785 nm excitation and has the ability to avoid fluorescence background in the Raman spectra. The availability of compact, robust, and reliable deep-UV laser sources has been always considered a major bottleneck problem on implementing this spectroscopic technique for NASA's space-borne applications. TIPD proposes to develop an ultrastable, compact, and long-lived deep-UV laser source for Raman spectroscopy based on our substantial experiences and facilities in developing single-frequency fiber lasers and solid-state deep-UV laser sources. Cooperating with the University of Arizona, we will develop an ultrastable and compact high power single-frequency single-polarization fiber laser system at 976 nm. The deep-UV laser source at 244 nm will be generated through two successive frequency doubling systems. In this phase I program, we will demonstrate deep-UV generation though frequency quadrupling of a 976 nm single-frequency fiber laser. In phase II, a deep-UV laser prototype meeting all the criteria of NASA's applications will be developed.

Benefits: Deep-UV Raman spectroscopy is a powerful tool to identify a variety of gas, liquid, and solid materials in the universe. Compact and ultrastable deep-UV laser sources can be used for planetary compositional, geological, and mineralogical analyses, planetary sample acquisition and habitability assessment, the search for past life on Mars, and human protection in aerospace.

Deep UV sources can be broadly used for Raman spectroscopy, laser cooling and trapping, laser inspection, optical data storage, metrology, biomedical applications, and laser lithography. Besides as ultra-stable narrow-linewidth laser sources for nonlinear wavelength converter, the single-frequency fiber lasers at 976 nm can also be used for low noise laser pumps for a variety of lasers at 1 ??m and 1.5 ??m. The 488 nm blue lasers have potential applications in submarine imaging, sensing, communications, data storage, undersea oil exploration, full color displays, and medicine.