Designs for improving plasmonic nanowire microcavity quality factor

Abstract

Plasmonic nanolasers have been demonstrated in multiple structures, among which semidconductor-metal (SM) plasmonic nanowire laser has simple structure and is suitable for electric pumping. A typical SM plasmonic nanowire laser consists of a high-quality perovskite nanowire laying on the ultra-flat single-crystal silver film. Due to the intrinsic ohmic loss of metal and high radiation loss of nanowire facets, SM plasmonic nanowire laser has features of low quality factor and high threshold. Here, we report a series of designs for improving the quality factor of the plasmonic nanowire microcavities. First, based on the principle of distributed Bragg reflector (DBR), we design 4 forms of structure to enhance the reflectivity of the microcavity nanowire facets. Our simulation results show that one of the designs, dielectric/air DBR at the end of nanowire, owns largest reflectivity. Then the dielectric/air DBR is applied to the plasmonic nanowire laser microcavity. The simulation results indicate that the quality factor of microcavity is improved by more than 75%. This design is easy to implement in the semiconductor process and is able to be applied in the high Q-factor semiconductor-metal (SM) plasmonic nanowire lasers in the near future.