Broadband sum-, difference-frequency generation and enhancement governed by Tamm state

Considering the second-order nonlinear effects of nonlinear media, utilizing the dynamically tunable property of field localization in aperiodic nonlinear hyperstructure (HS), the dependence relationship between the nonlinear processes generated by dual optical incidence and the layered HS is presented. Sum and difference frequency generation with a certain bandwidth is realized through the correspondence between conversion frequency and nonlinear medium thickness. The transfer S-matrix method is applied to calculate the efficiency of frequency conversion, where the conversion from T -matrix to S -matrix formalism enhances numerical stability while reducing the complexity of expressions. Matching the frequencies of two incident waves with Tamm resonances inside two band gaps enhances the nonlinear effects by exploiting the field localization characteristics.