Alkali lasers: a new type of scalable high-power lasers

Abstract

Historically, an optically pumped alkali (potassium) vapor laser was the first laser proposed by A.L. Schawlow and C.H. Townes in 1958, but was not experimentally demonstrated at that time. In the next 45 years, many experiments with alkali vapors were performed that demonstrated stimulated emission, gain and amplified spontaneous emission. However, the real interest in alkali vapor lasers appeared in the last several years, when really efficient lasing in Rb and Cs vapors was demonstrated. The US Air Force Academy performed a variety of experiments on alkali lasers, including the demonstration of efficient Rb, Cs and K vapor lasers, power scaling experiments with multiple diode laser pumping sources and experiments on diode pumped alkali vapor amplifiers. As a result of this effort we have increased the alkali lasers output power to tens of watts in continuous wave operation. In this paper we present a review of the most important achievements in high power alkali lasers research and development, discuss some problems existing in this field.