Some questions of optimal focusing during second harmonics generation in nonlinear crystals. Part 2. Results of numerical calculations
V.O. Troitskii
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634021, Russia
Keywords: генерация второй гармоники, одноосный нелинейный кристалл, скрещенные цилиндрические линзы, оптимальная фокусировка, second harmonics generation, uniaxial nonlinear crystal, crossed cylindrical lenses, optimal focusing
Abstract
The problem of second harmonics generation (SHG) of monochromatic spatially coherent paraxial radiation in homogeneous quadratic nonlinear uniaxial crystals is considered theoretically. It is assumed that the laser radiation is focused into a crystal by two crossed cylindrical lenses with different focal lengths. The aim of this study is to find dependences of optical focusing parameters on the primary radiation power. The work consists of two parts. Part 2 presents main results of numerical calculations. It is shown that optimal focusing parameters first vary insignificantly as the primary radiation power increases. Then, beginning from a certain power value, which depends on the initial conditions of the problem, the SHG efficiency maximum becomes attainable at weaker and weaker focusing, and the value of the efficiency maximum monotone increases, probably tending to a value close to 100% under an infinite increase in the power.
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