Described is research work aimed at the development of techniques for frequency tripling laser radiation which is incident on mixtures of metal vapors and inert gases. Principal accomplishments of the program include: the demonstration of the first nonlinear optical technique in the vacuum ultraviolet region of the spectrum; the generation of kW peak powers at 1773 A, 1520 A, and 1182 A; the development of a very general analysis for studying the potential conversion efficiency in the alkali metal-inert gas system; and most recently the proposal and demonstration of the very simple technique of third harmonic generation in mixtures of inert gases. (Author).