An Appropriate Nanorod-Based Plasmonic Nanolaser for Utilizing as a Waveguide-Integrated Plasmon Source

One of the leading obstacles in scaling down semiconductor lasers in all three dimensions is the diffraction limit. Experimental results show that plasmonic cavities can overcome this great challenge. However, one of the main problems is how to utilize these structures more efficiently as integrated devices in optoelectronic and plasmonic circuits since they have low coupling efficiency. One solution is to benefit metal-insulator-semiconductor (MIS) nanostructures with inline or waveguide-integrated nanocavities to achieve higher coupling efficiency. In this paper, a plasmonic nanolaser based on semiconductor-insulator-metal-insulator-semiconductor (SIMIS) nanostructure is proposed and investigated. This structure is suitable for utilizing as a waveguide-integrated nanocavity in a hybrid plasmonic waveguide based on coupled nanorods. Simulation results based on the finite element method (FEM) show that the presented structure with a radius of 40 nm and insulator layer thickness of more than 8.7 nm has lower threshold and simultaneously lower normalized mode area at the lasing wavelength of 490 nm compared to the previously reported MIS nanostructure with the same parameters. So, the SIMIS based spaser may result in a proper performance as a waveguide-integrated plasmon source.