1 / 2017-07-12 15:48:32

Plasmonic enhancement of second harmonic generation from Ag-coated ZnTe/ZnO nanowires

second harmonic generation,light-matter interaction,metal-semiconductor hybrids,nanowire

In recent years, nonlinear optical properties of metal-integrated semiconductors have attracted a lot of attentions due to their potential applications in sub-wavelength biological imaging [1], nonlinear optical microscopy [2], and ultraviolet source [3]. Second harmonic generation (SHG) is a nonlinear optical process that converts the incident fundamental wave (FW) with frequency into another wave with double frequency . It has been demonstrated that metal-coated nonlinear medium shows an unparalleled ability to enhance the SHG intensity of devices compared to bare nonlinear medium through enhancing electromagnetic field intensities in the nonlinear medium [4]. In this work, we demonstrated dramatic plasmonic enhancement of second harmonic generation from Ag-coated ZnTe/ZnO nanowires by coupling with Ag film (Fig.1). The intensity of the SHG from Ag-coated ZnTe/ZnO NW is about 30 times higher than that from the same bare NW under TM excitation, and the conversion efficiency is about . The coated Ag film serves as an efficient mirror to keep the light from leaking out, which leads to the enhancement of the electric field distribution in the NW. The combination of the light concentration of Ag film and the dielectric resonance of NW opens up new avenues for enhancing coherent, nonlinear light-matter interactions and achieving high conversion efficiency of the SHG.