Title Cascaded nonlinearity induced spatial domain effects in a high power femtosecond optical parametric oscillator /
Authors Stasevičius, Ignas ; Vengris, Mikas
DOI 10.1364/OE.404177
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Is Part of Optics express.. Washington : Optical Society of America. 2020, vol. 28, no. 22, p. 33490-33503.. ISSN 1094-4087
Keywords [eng] supercontinuum generation ; soliton formation ; self-compression
Abstract [eng] We have investigated the effect of cascaded optical nonlinearity on the spatial beam properties of a femtosecond optical parametric oscillator (OPO). The OPO was operated with a tunable phase mismatch by varying the angle of the nonlinear crystal. The cascaded nonlinearity induced self-focusing and defocusing changed resonator's stability and impacted mode properties. With tuning of a phase mismatch, the calculated parabolic part of cascaded nonlinearity lens focal length changes from f similar to 30 mm (D similar to 33 m(-1) at Delta theta similar to -0.5 degrees) to infinity and back to f similar to -110 mm (D similar to -9 m(-1) at Delta theta similar to 0.9 degrees) in the LBO nonlinear crystal. Such high power nonlinear lenses in a cavity operated near its stability limit promoted the generation of axially asymmetric or pass-to-pass unstable resonator modes. It was shown that phase mismatched optical parametric oscillation changes the physical character of the resonator from linear to ring-like with two nonlinear crystals having two different focusing powers. Calculations showed that the QCN induced spatial nonlinear phase should lead to severe longitudinal chromatic aberrations for broad spectrum pulses. A numerical simulation in XYZ spatial domain and calculations using ABCD matrix approach confirmed the physical mechanisms underlying the experimental results and allowed for the interpretation of the observed effects.
Published Washington : Optical Society of America
Type Journal article
Language English
Publication date 2020
CC license CC license description