CC BY
10*
ALT'23
The 30th International Conference on Advanced Laser Technologies
LS-I-20
Laser on metastable atoms of inert gases with optical pumping
P. Mikheyev1, A. Torbin12, A. Chernyshov1, M. Zagidullin12, M. Svistun1, N. Ufimtsev1
1- P.N. Lebedev Physical Institute, Samara branch, 221 Novo-Sadovaya st. Samara, 443011, Russia 2- Samara National Research University, 34, Moskovskoye shosse, Samara, 443086, Russia
Optically pumped all-rare-gas laser (OPRGL) which was proposed recently [1], utilizes metastable atoms of Ne, Ar, Kr and Xe as lasing species and have a potential for scaling to a high-power system with good beam quality. Like alkali atoms, rare gas metastables host just one electron on the outer shell, making OPRGL kinetically analogous to the extensively studied diode pumped alkali laser (DPAL) [2]. However, OPRGL has a sound advantage - its active medium is chemically inert. Both DPAL and OPRGL are three-level systems where energy transfer from the optically pumped level is provided in collisions with a bath gas. However, in the most extensively studied cesium-based DPAL light hydrocarbons have to be used to provide efficient energy transfer at a moderate pressure. In that case, the presence of the excited alkali atoms leads to a complex chemistry that finally results in degradation of the laser medium. In OPRGL, energy transfer is efficient at an atmospheric pressure when He is the collisional partner. The pump wavelengths for the OPRGL's fall in a well-developed spectral region for laser diodes and the energy from large arrays of diodes can be combined to a high-power, high-quality beam. All lasing wavelengths fall in the atmospheric transparency window. Rate coefficients for collisional energy transfer from pump to upper laser level are about 10-11 cm-3 s-1. Theoretical estimations [3] showed that the specific laser output in Ar:He mixture can be on the order of 102 W cm-3 with overall efficiency (including discharge requirements) more than 50%. A discharge system should provide the metastables' number density about 1013 cm-3 or larger at near atmospheric pressure and this is the key problem for this class of lasers. Analysis of the discharge in Ar:He mixture [3] showed that efficient Ar(1ss) production is possible when E/N« 10 Td or larger. That rules out cw discharges and leaves a repetitively pulsed nanosecond discharge as the most suitable for an OPRGL. In this report the successful experiments with OPRGL lasing are reviewed and possible approaches for its further development and scaling are discussed.
[1] J. Han, M. Heaven, Gain and lasing of optically pumped metastable rare gas atoms, Optics Letters, vol. 37, pp. 2157-2159, (2012).
[2] W. Krupke, Diode pumped alkali lasers - A review, Progress in Quantum Electronics, vol. 36, pp. 4-28, (2012).
[3] A. Demyanov, I. Kochetov, P. Mikheyev, Kinetic study of a cw optically pumped laser with metastable rare gas atoms produced in an electric discharge, Journal of Physics D: Applied Physics, vol. 46, p. 375202, (2013).
