Highly-sensitive detection techniques are required in many aspects of biotechnology. One highly sensitive technique for detecting trace levels of proteins and other biomolecular species is capillary electrophoresis with laser-induced-fluorescence detection. Capillary electrophoresis with direct laser excitation of biochemical species using ultraviolet light is especially sensitive. The object of this Phase I program is to determine the feasibility of a compact and efficient optical source in the 266nm ultraviolet spectral region by frequency-quadrupling the continuous-wave output of a diode- pumped Nd:YAG laser. The long range goal of this program is to develop a 266nm laser source in the 10-100 mW power range for use in clinical instrumentation. The compactness and reliability of such sources should lead to the development of instrumentation useful in recombinant DNA, monoclonal antibody and biopharmaceutical research.