Mesoscopic Transport of the Second-harmonic Light Generated within a Nonlinear Disordered Medium

Nonlinear disordered photonic media uniquely combine multiple scattering with nonlinear light generation; a combination that has been recently shown to offer a versatile platform for applications in encryption, all-optical logic gates, and photonic machine learning [1], [2]. These materials consist of strongly scattering nanodomains with a high second-order susceptibility tensor. When excited by a fundamental beam, each nanodomain generates second-harmonic (SH) waves, which are scattered with random amplitudes and phases. The interference of the generated waves enables efficient nonlinear light generation without stringent phase-matching conditionsa process known as random quasi-phase matching.