Surface-Plasmon-Polariton Laser based on an Open-Cavity Fabry-Perot Resonator

TL;DR

This paper reports the development of a room-temperature, ultra-narrow linewidth laser based on surface plasmon polaritons in an open Fabry-Perot cavity, enabling potential applications in sensing and on-chip communications.

Contribution

It introduces a novel open-cavity plasmonic laser with a subwavelength gain medium and a nanoslit sensor interface, advancing nanolaser technology and sensing capabilities.

Findings

Achieved visible frequency ultra-narrow linewidth lasing at room temperature.

Demonstrated high-sensitivity refractive-index sensing using evanescent coupling.

Implemented an open-cavity design for integrated nanophotonic applications.

Abstract

Recent years have witnessed growing interest in the development of small-footprint lasers for potential applications in small-volume sensing and on-chip optical communications. Surface-plasmons, electromagnetic modes evanescently confined to metal-dielectric interfaces, offer an effective route to achieving lasing at nanometer-scale dimensions when resonantly amplified in contact with a gain-medium. Here, we achieve visible frequency ultra-narrow linewidth lasing at room-temperature by leveraging surface plasmons propagating in an open Fabry-Perot cavity formed by a flat metal surface coated with a subwavelength-thick layer of optically-pumped gain medium and orthogonally bound by a pair of flat metal sidewalls. Low perturbation transmission-configuration sampling of the lasing plasmon mode is achieved via an evanescently coupled recessed nanoslit, opening the way to high-figure-of-merit refractive-index sensing of analytes interacting with the open cavity.