Impact of domain size and orientation on broadband second-harmonic generation using random quasi-phase matching in disordered media

This paper presents second-order broadband optical generation based on random domain size orientation in a birefringent nonlinear crystal. A higher degree of structural disorder seems to enhance the efficiency in response to an increasing number of domains, while the higher level of disorder growth is characterized by a wider dispersion. This observation holds true across various domain sizes, rendering the system robust to structural fluctuations. The simulation results for broadband second-harmonic generation in birefringent, transparent media with arbitrary domain configurations are explored in this paper. Additionally, the idea of expanding the mid-infrared second-harmonic generation’s bandwidth is described analytically for the proposed configuration. The analysis includes the disordered assembly of magnesium-oxide-doped lithium niobate and investigates the impact of birefringence on the random quasi-phase matching process in both monodispersed and polydispersed assemblies, considering the random rotation of different domains. The efficiency of 3.49% and 2.01% with 3-dB bandwidth of 135[Formula: see text]nm and 210[Formula: see text]nm, centered at 1170[Formula: see text]nm and 1135[Formula: see text]nm for monodispersed and polydispersed cases, respectively, have been obtained in phase matching case.