Asymmetric Spectral Broadening of 0.3 ps, 1030 nm Laser Pulse in BaWO₄ Crystal

Abstract

Asymmetric spectral broadening combined with an efficient transient stimulated Raman scattering is experimentally demonstrated in a BaWO₄ crystal pumped by 0.3 ps 515 nm laser pulse. This effect is explained by a non-instantaneity of the orientational Kerr nonlinearity that is for the first time observed in a solid medium. In this paper, we verify the nature of the asymmetric spectral broadening in a BaWO₄ crystal related to the “slow” Kerr nonlinear response. We demonstrate this fact by experiments with 0.3 ps 1030 nm laser pulse, namely, in conditions of no evident effect of stimulated Raman scattering on a self-phase-modulation-induced broadening of the pump pulse spectrum. The nonlinear refractive index and its decay time in the BaWO₄ crystal retrieved from 1030 nm wavelength data are in a good agreement with ones obtained for 515 nm wavelength.