Nonlinear frequency up-conversion via double topological edge modes

作者：Cheng Qian, Ka Hei Choi, Raymond P. H. Wu, Yongliang Zhang, Kai Guo, Kin Hung Fung · 发表于：Optics Express · 年份：2018 · DOI：10.1364/oe.26.005083 · 被引用次数：19 · 研究领域：Plasmonic and Surface Plasmon Research、Photonic Crystals and Applications、Advanced Fiber Laser Technologies

We study the nonlinear frequency up-conversion in a plasmonic thin film sandwiched between one-dimensional photonic crystals (PCs) of different Zak phases by rigorous numerical time-domain nonlinear hydrodynamic calculations. We show that the proposed hetero-structure can support robust fundamental and high-order topological edge modes that simultaneously enhance the third-harmonic generation. Numerical simulations also show that femtosecond pulses can excite double topological edge modes through optical tunneling in band gaps, leading to a large nonlinear response. The obtained third harmonic generation (THG) conversion efficiency of the hetero-structure is three orders of magnitude larger than that of a single plasmonic film. The results presented here may open new avenues for designing high-efficiency nonlinear photonic devices.