Rational design of a ZnO nanowire laser on a surface plasmon polariton.

Plasmonic lasers, which use the strong confinement of surface plasmon polaritons, are key parts to realize ultracompact coherent light sources at deep subwavelength scales. We propose a plasmonic laser composed of a silicon substrate, ZnO nanowire, dielectric layer, metal layer, and electrode. In this structure, the superimposed coupling of the surface plasmon mode at the metal interface with the high refractive index gain nanowire mode makes the electric field in the spacer layer significantly enhanced. The ZnO nanowire is used as gain material to provide gain compensation. The optical and electrical properties are simulated with the geometric parameters and dielectric layer material. The results show that the structure has strong confinement of the optical field and can realize a deep subwavelength constraint at a lower threshold level. It provides theoretical support for realizing ultracompact coherent light sources.