Theory of Metal-Cavity Surface-Emitting Microlasers and Comparison With Experiment

We present a theoretical model of the recently demonstrated metal-cavity surface-emitting microlaser, which lases at room temperature with continuous-wave operation. A transfer-matrix method with the effective index of the guided mode as the input and an emission model that incorporates the modal characteristics explain the experimental results, such as the asymmetrical lineshape well. We also discuss the design rules and approaches to improve the performance of the nanoscale laser. With the combination of the metal coating and distributed Bragg reflector, of which the multilayer thicknesses are redesigned according to the modal dispersion of a small metallic waveguide, the laser size can be potentially reduced to the subwavelength regime. In addition, our rigorous rate-equation model explains the output power versus injection current with excellent agreement.