Vol. 39, issue 09, article # 12

Abstract:

The paper continues the theoretical study [1]. Unlike [1], this work analyzes situations where the power of fundamental radiation and, hence, the SHG efficiency are sufficiently high, but the preset field approximation (PFA) is not applicable. Estimates are made with the use of numerical methods for solving the full set of reduced nonlinear wave equations. It is shown that the abandonment of PFA does not qualitatively change the main conclusions of [1]. If restrictions on the beam damage threshold of a nonlinear medium are neglected, the maximum possible SHG efficiency is achieved upon optimal focusing of laser radiation at the center of a crystal. In the cases where the pump power density should be reduced to prevent crystal damage, telescope systems are preferable to long-focus lenses.

Keywords:

second harmonic generation, set of reduced nonlinear equations, fast Fourier transform, nonlinear process optimization, telescope aspect ratio, amplitude profile

References:

1. Troitskii V.O. Generatsiya vtoroi garmoniki s ispol'zovaniem teleskopicheskikh sistem. Part 1 // Optika atmosf. i okeana. 2025. V. 38, N 4. P. 320–328. DOI: 10.15372/AOO20250411.
2. Kobernichenko V.G. Osnovy tsifrovoi obrabotki signalov: ucheb. posobie. Ekaterinburg: Ural. feder. un-t, 2018. 150 p.
3. Voropaeva N.V., Novikov S.Ya., Fedina M.E. Diskretnoe preobrazovanie Fur'e v obrabotke signalov: ucheb. posobie. Samara: Samarskii un-t, 2015. 48 p.