A nanolaser with extreme dielectric confinement

TL;DR

This paper introduces a dielectric nanolaser that achieves extreme light and matter confinement within the same nanostructure, enabling room-temperature continuous-wave lasing with reduced thresholds by enhancing light-matter interactions.

Contribution

It demonstrates a novel dielectric nanolaser with simultaneous localization of light and carriers, surpassing diffraction limits without quantum confinement, and introduces a new interaction volume concept.

Findings

Achieved subwavelength mode and carrier volumes without quantum confinement.

Observed self-alignment of light and matter reduces laser threshold.

Enabled room-temperature continuous-wave lasing with enhanced light-matter interaction.

Abstract

The interaction between light and matter can be enhanced by spatially concentrating the light field to boost the photon energy density and increasing the photon dwell time to prolong energy transfer between light and matter. Traditionally, strong spatial light localization has been achieved using plasmonics, which, despite its effectiveness, entails ohmic losses. Recent advances in nanostructured dielectrics offer an avenue for achieving strong light confinement without metallic losses. However, previous studies primarily focused on minimizing the optical mode volume without adequately addressing light-matter interactions. Here, we develop a nanolaser that simultaneously localizes the electromagnetic field and excited carriers within the same region of a dielectric nanobridge. This extreme dielectric confinement of both light and matter achieves a mode volume below the diffraction limit and a subwavelength carrier volume without the introduction of lateral quantum confinement, enabling continuous-wave lasing at room-temperature. Moreover, we observe a strong correlation between the mode field and carrier distribution, and unexpectedly, the enhanced mode field localization automatically leads to more pronounced carrier localization, promoting self-alignment of light and matter, which significantly reduces the laser threshold. We quantify the intensified light-matter interaction with a newly proposed interaction volume, which generalizes the concept of mode volume to a broad class of active media. Our work lays the ground for developing ultra-efficient optoelectronic devices by greatly enhancing light-matter interactions through advanced material nanostructuring.