Higher-order Kerr effect including the uncertainties of their nonlinear coefficients

Abstract

We numerically generalize the nonlinear propagation Schrödinger equation by introducing contribution (to the nonlinear refractive index variation) factor α , only for the numerical investigation of the higher-order Kerr effect (HOKE) with the higher-order Kerr nonlinear coefficients (n₄, n₆, n₈). Our results confirm that the uncertainties of the higher-order Kerr nonlinear coefficients have a non-negligible effect on propagation of the intense femtosecond laser pulse in air, when the HOKE is considered. The smaller the α the larger the defocusing that is caused by HOKE, and the weaker the clamping intensity, and the remoter the position where the filamentation starts, and the longer the length of filament. Moreover, the higher-order Kerr terms play a role before the plasma defocusing, if the HOKE is considered.