Frequency Tuning and Efficiency Enhancement of High Power FIR Lasers

Abstract

National Magnet Laboratory Massachusetts Institute of Technology Cambridge, Mass. 02139 Introduction Laser pumped molecular lasers have many useful applications including radar, plasma diagnostics and spectroscopy. This range of applications would be expanded considerably with the development of highly efficient and/or frequency tunable laser pumped lasers. In this paper, we describe techniques for achieving these goals, techniques based on excitation of a molecular gas far off resonance. We have already demonstrated such excitation in CO2 laser pumping of CH3F gas. Experimental and theoretical work has been carried out on a tunable far infrared (FIR) laser based on Raman scattering of tunable CO2 laser pump radiation in molecular gases. Good agreement between theory and experiment is obtained. Stimulated multiphoton emission processes are considered as a method of achieving efficiency enhancement in laser pumped lasers. These processes achieve high efficiency through the simultaneous emission of several low frequency photons for each high frequency photon absorbed.