Gain and lasing of optically pumped metastable rare gas atoms

TLDR

Optically pumped alkali vapor lasers are under development, but metal atom reactivity poses challenges; however, metastable rare gas atoms in the np(5)(n+1)s (3)P(2) state have similar spectral properties to alkali metals. The objective is to construct high‑powered lasers that also exhibit excellent beam quality. The authors used three‑level lasing schemes exciting the np(5)(n+1)p←np(5)(n+1)s transitions, with He or Ar as collisional energy transfer agents to establish population inversion. Gain and lasing were observed in optically pumped Ar, Kr, and Xe, demonstrating that these systems can use inert, room‑temperature gases as reagents.

Abstract

Optically pumped alkali vapor lasers are currently being developed in several laboratories. The objective is to construct high-powered lasers that also exhibit excellent beam quality. Considerable progress has been made, but there are technical challenges associated with the reactivity of the metal atoms. Rare gas atoms (Rg) excited to the np(5)(n+1)s (3)P(2) configuration are metastable and have spectral properties that are closely similar to those of the alkali metals. In principle, optically pumped lasers could be constructed using excitation of the np(5)(n+1)p←np(5)(n+1)s transitions. We have demonstrated this potential by observing gain and lasing for optically pumped Ar(*), Kr(*) and Xe(*). Three-level lasing schemes were used, with He or Ar as the collisional energy transfer agent that established the population inversion. These laser systems have the advantage of using inert reagents that are gases at room temperature.