Features of noncollinear parametric generation light in LiNbO_3 crystal pumped by the fundamental radiation of Nd:YAG laser

摘要

Theoretical and experimental studies the features of parametric generation light in LiNbO_3 with noncollimnear phase matching from noncollinear angle i_(23), i.e. angle between pump wave vector and resonant signal wave vector, are presented. It was shown that at the small angle i_(23)< 0,3 deg four nonlinear processes can simultaneously take place: these processes are noncollinear parametric conversion of the 1.0642μm into the signal and an idler waves; second-harmonic generation of the signal; noncollinear difference-frequency mixing of the doubled signal and the idler; parametric conversion of the doubled signal into new pair: the signal and an idler waves. It is shown that the maximum efficiency of noncollinear OPO takes place for tangential phase-matching at i_(23) ≈ 0,9 deg. Spectral broadening of the signal wave of LiNbO_3 noncollinear OPO was studied. Theoretically it is shown that the spectral bandwidth of the signal wave depends on the divergence of the signal wave.