Enhancement of second harmonic generation from three layers hybrid dielectric/metal/dielectric nanospheres

Abstract

Due to the significant linear and nonlinear (NL) optical properties, hybridization of high-index dielectric and plasmonic materials can result in generating NL optical phenomena with high efficiency compared to the individual nanostructures made of these materials. The efficient surface second harmonic generation (SSHG) from three layers Si/Au/Si (SAS) nanospheres are investigated by the finite element method. The resonance wavelengths are determined by the numerical calculation of the linear spectral response. Then, by calculating the SSHG from each interface of the SAS at resonance wavelengths, it is shown that the core surface (the middle interface) has the dominant contribution at shorter (longer) wavelengths to enhance the SSHG. Finally, the total SSHG is compared to individual silicon nanosphere (SNS), which shows enhancing the efficiency of SHG up to 50 times at some resonance wavelength. The results of this work can pave the way for investigating and enhancing the efficiency of nano-photonic devices such as nano-lasers and nano-sensors.