Simultaneously surface- and edge-emitting plasmonic laser operating in the near-infrared region

Abstract

Near-infrared (IR) plasmonic lasers are a crucial stepping stone toward building sustainable nanoscale optoelectronic circuitry. Nevertheless, plasmonic lasers are at their infancy, and optimized designs for improved characteristics and novel applications are essential. We design an efficient plasmonic laser that simultaneously works in the near-IR region as a surface- and edge-emitting laser with collimated far-field beam pattern. While the surface emission is enhanced with a planar two-dimensional (2D) metal nanohole array (NHA) interfaced with the gain medium, the edge emission is enhanced with a 2D array of grooves. Additionally, 2D NHA or grooves on the metal layer collimate the far-field beam pattern of surface emission in the forward and backward direction, respectively. By contrast, the edge emission diverges at the far-field with an angle-resolved beam pattern from -90° to 90°. We propose and design a plasmonic collimator that uses groove-aperture nanostructures carved on gold slabs mounted on the laser facet to collimate the far-field beam patterns for edge emission. We determine the optimal dimensional parameters of the collimator. The optimized collimator produces a far-field beam that is focused to a narrow spot of 3° × 4° only.