Modeling of ultrabroadband and single-cycle phenomena in anisotropic quadratic crystals

Abstract

We present a comprehensive model to describe the propagation of single-cycle and broadband optical pulses in anisotropic, dispersive, and nonlinear materials. Two nonlinear coupled wave equations describe the dynamics and interactions of optical pulses in uniaxial second-order nonlinear materials. The equations are first order in the propagation coordinate and are valid for arbitrarily wide pulse bandwidth, providing an accurate modeling of the evolution of ultrabroadband pulses also when the separation into different coupled frequency components is not possible or not profitable. We exploit this model to simulate recently observed femtosecond single-cycle multiterahertz transients in gallium selenide and to predict harmonic generation and spectral broadening in the visible and mid-infrared in lithium niobate.