CC BY
6The 30th International Conference on Advanced Laser Technologies LS-I-19
ALT'23
The role of rate constants measurement for the development of gas lasers
A. Torbin1'2
1 - Lebedev Physical Institute, Samara Branch, Novo-Sadovaya str., 221, Samara, Russia, 443011 2 - Samara National Research University, Moskovskoye shosse, 34, Samara, Russia, 443086
Main author email address: [email protected]
To date, the most promising laser systems that would combine high power and diffraction quality of radiation are hybrid gas lasers with diode optical pumping. Systems of this type include, for example, diode pumped alkali metal vapor lasers (DPAL) and optically pumped metastable heavy rare gas lasers (OPRGL). The advantage of a gaseous active medium in comparison with a solid one is the lower influence of temperature that affect the output beam quality and the appearance of optical inhomogeneities. Due to this, a larger limiting energy output per volume unit of the active medium is achieved in a gas laser. The photon source in gas lasers is an electronically or vibrationally excited particle Ex*. The main parameters of the laser operation, such as the gain or specific energy output, are expressed in terms of the number densities of these excited particles. Accordingly, laser efficiency and its limiting parameters can only be calculated with exact knowledge of the rates of chemical and energy transfer processes in which Ex* are produced and destroyed. In turn, the physical quantity that determines the rate of chemical reactions is the rate constant. Consequently, development of accurate mathematical models and the design of new gas laser systems is fundamentally impossible without experimentally measured rate constants of processes involving Ex*. The measurement of these constants requires the use of modern research methods and precise scientific equipment.
For many years, our scientific group has been measuring the rate constants of processes occurring in the active medium of various lasers. In studies aimed at the development of DPAL [1,2], the rate constants of the deactivation processes of the electronically excited rubidium atoms in collisions with diluent gases H2, CH4, and C2H6 were measured, and a conclusion was made about the preferential use of methane in this role. We measured a number of kinetic constants of processes involving thermalized and vibrationally excited singlet oxygen 02(a,u), vibrationally excited ozone O3(u), and O atoms occurring in the active medium of an electric-discharge oxygen-iodine laser (EOIL) [3-5]. In [5] an explanation was given for the sharp drop in 02(a) number density at the output of an electric discharge generator of singlet oxygen in EOIL, based on the occurrence of the previously disregarded reaction 02(a) + O3(u). Currently, the Samara branch of LPI is working on measuring the temperature dependences of the rate constants of energy transfer processes involving metastable argon atoms Ar* in a mixture with helium He, which are necessary for the development of the OPRGL. Since Ar* atoms in OPRGL are produced in the plasma of a repetitively pulsed discharge, knowledge of the temperature dependences of the rate constants becomes critical for the development of this new promising laser system.
[1] V. N. Azyazov, A. P. Torbin, A. M. Mebel, S. M. Bresler and M. C. Heaven, Product channels of the reactions of Rb(62P) with H2, CH4 and C2H6, Journal of Quantitative Spectroscopy & Radiative Transfer, vol. 196, pp. 46-52, (2017).
[2] V. N. Azyazov, A. P. Torbin, S. M. Bresler, A. M. Mebel and M. C. Heaven, Removal of Rb(62P) by H2, CH4 and C2H6, Optics Letters, vol. 41, pp. 669-672, (2016).
[3] A. P. Torbin, A. A. Pershin, A. M. Mebel, M. V. Zagidullin, M. C. Heaven and V. N. Azyazov, Collisional relaxation of 02(a'A, u = 1, 2, 3) by CO2, Chemical Physics Letters, vol. 691, pp. 456-461, (2018).
[4] A. A. Pershin, A. P. Torbin, M. V. Zagidullin, A. M. Mebel, P. A. Mikheyev and V. N. Azyazov, Rate constants for collision-induced emission of 02(a'Ag) with He, Ne, Ar, Kr, N2, CO2 and SF6 as collisional partners, Physical Chemistry Chemical Physics, vol. 20, pp. 29677-29683, (2018).
[5] V. N. Azyazov, A. P. Torbin, P. A. Mikheyev, A. A. Pershin and M. C. Heaven, Kinetics of Oxygen Species in an Electrically Driven Singlet Oxygen Generator, Chem. Phys., vol. 463, pp. 65-69, (2015).
