Plasmonic lasing of nanocavity embedding in metallic nanoantenna array

TL;DR

This paper reports a room-temperature, low-threshold plasmonic nanolaser using a nanoantenna array design, addressing high lasing thresholds and poor optical pumping efficiency in subwavelength nanocavities.

Contribution

It introduces a cavity-embedded nanoantenna array design enabling low-threshold, reproducible plasmonic nanolasers operable at room temperature.

Findings

Lasing threshold of ~2.70 MW/mm² achieved

Mode volume approximately 0.22(λ/2n)^3

Nanoantenna array enhances optical pumping efficiency

Abstract

Plasmonic nanolasers have ultrahigh lasing thresholds, especially those devices for which all three dimensions are truly subwavelength. Because of a momentum mismatch between the propagating light and localized optical field of the subwavelength nanocavity, poor optical pumping efficiency is another important reason for the ultrahigh threshold but is normally always ignored. Based on a cavity-embedded nanoantenna array design, we demonstrate a room-temperature low-threshold plasmonic nanolaser that is robust, reproducible, and easy-to-fabricate using chemical-template lithography. The mode volume of the device is~0.22({\lambda}/2n)3 (here,{\lambda} is resonant wavelength and n is the refractive index), and the experimental lasing threshold produced is ~2.70MW/mm2. The lasing polarization and the function of nanoantenna array are investigated in detail. Our work provides a new strategy to achieve room-temperature low-threshold plasmonic nanolasers of interest in applications to biological sensoring and information technology.