Chiral emission of vortex microlasers enabled by collective modes of guided resonances

TL;DR

This paper demonstrates chiral vortex emission from microlasers by harnessing collective modes of guided resonances in photonic crystal slabs, enabling stable, low-threshold, and energy-efficient vortex lasing with potential applications in quantum technologies.

Contribution

It introduces a novel approach to achieve chiral vortex microlasers using collective modes from hybridized guided resonances in photonic crystals, with experimental validation at room temperature.

Findings

Achieved stable single-mode vortex lasing with low threshold.

Demonstrated chiral emission via asymmetric pumping.

Validated vortex patterns through polarization and interference imaging.

Abstract

Vortex lasers have attracted substantial attention in recent years owing to their wide array of applications such as micromanipulation, optical multiplexing, and quantum cryptography. In this work, we propose and demonstrate chiral emission of vortex microlaser leveraging the collective modes from omnidirectionally hybridizing the guided mode resonances (GMRs) within photonic crystal (PhC) slabs. Specifically, we encircle a central uniform PhC with a heterogeneous PhC that features a circular lateral boundary. Consequently, the bulk GMRs hybridize into a series of collective modes due to boundary scatterings, resulting in a vortex pattern in real space with a spiral phase front in its radiation. Benefiting from the long lifetime of GMRs as quasi-bound state in the continuum and using asymmetric pumping to lift the chiral symmetry, we demonstrate stable single-mode lasing oscillation with a low optical pumping threshold of $18~\mathrm{kW/cm^2}$ at room temperature. We identify the real-space vortex through polarization-resolved imaging and self-interference patterns, showing a vivid example of applying collective modes to realize compact and energy-efficient vortex microlasers.