Herald of the Bauman Moscow State Technical University Series Natural Sciences

Influence of a Scattering Medium Consisting of Potassium Atoms on the Luminescent Signal Decay Time: Theoretical Investigation by Monte Carlo Method

V.M. Yamshchikov

Published Jun 1, 2022• 1 citation

Abstract

The study solves the problem of the luminescent photons propagation in a resonantly absorbing medium consisting of atoms of the studied substance and a buffer inert gas. The Monte Carlo method was used in numerical experiments carried out to simulate real processes that occur in a chamber designed to determine the lifetime of an individual atom in an excited state by the method of measuring the luminescence intensity decay time. Findings of the research show that when luminescent photons are repeatedly scattered (scattering means the process of absorption and re-emission of a photon by an atom) in a medium, the luminescence decay time noticeably increases, reaching a value greater than the average lifetime of an individual atom in an excited state. The reflection of photons from the walls that make up the chamber can lead to errors in measuring the lifetime. The process of luminescence decay is studied theoretically for various detunings of the laser frequency from the resonant transition frequency. A three-level model of the atom and a model of complete frequency redistribution were applied. The study describes an algorithm based on the Monte Carlo method, which is used to model the three-level population kinetics, laser radiation transfer, radiation trapping, and frequency redistribution

DOI: 10.18698/1812-3368-2022-3-69-85

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