Optical surface polaritons of TM type at the nonlinear semiconductor–nanocomposite interface

TM-polarized optical surface polaritons in a nonlinear semiconductor–nanocomposite guiding structure have been considered. The nanocomposite consists of alternating layers of bismuth-containing garnet ferrite (BIG, Lu$_{3-x}$Bi$_{x}$Fe$_{5-y}$Ga$_{y}$O$_{12}$) and gallium–gadolinium garnet (Gd$_{3}$Ga$_{5}$O$_{12}$), and the semiconductor ($n$-InSb) has a cubic nonlinearity and is characterized by two components of the nonlinear susceptibility tensor. With allowance for the anisotropy of the optical properties of the nanocomposite, caused by the magnetization of the BIG layers, the dispersion relation has been obtained and analyzed and its solutions are shown to split into two pairs of high- and low-frequency branches. The influence of the electric field at the interface on the wave characteristics and the existence domains of nonlinear surface TM polaritons has been studied. By solving the inverse problem of finding the profile of the longitudinal electric component of the surface polariton, it has been found that the nonlinearity gives rise to soliton-like wave fields.