Dynamically Switchable Polarization Lasing between q-BIC and Bragg Resonance Modes

Abstract

Quasi-bound states in the continuum (q-BICs) enable low-threshold lasing through high-Q cavity modes, yet their polarization tunability remains constrained by nanostructure-imposed cavity symmetries. By engineering a microcavity with an optimized duty cycle (0.34), we demonstrate a polarization-switchable distributed feedback (DFB) laser with controlled emission transitions between dual off-Γ q-BIC lasing and single Γ-point Bragg resonance (BR) lasing through switching pump polarization. The switching mechanism shows unprecedented robustness in varying waveguide thickness and photonic crystal period of DFB structures. Our findings extend the capabilities of DFB lasers beyond their conventional limits, opening opportunities for nanophotonics, classical and quantum optics applications.

References in corpus (13)

• Asymmetric metasurfaces with high-$Q$ resonances governed by bound states in the continuum
• Resonantly Trapped Bound State in the Continuum Laser
• High-Q supercavity modes in subwavelength dielectric resonators
• Analytical Perspective for Photonic Bound States in the Continuum in Photonic Crystal Slabs
• Lasing in dark and bright modes of a finite-sized plasmonic lattice
• Observation of miniaturized bound states in the continuum with ultra-high quality factors
• Screened Strong Coupling of Excitons in Multilayer WS2 with Collective Plasmonic Resonances
• Ultra-low threshold continuous-wave quantum dot mini-BIC lasers
• Bound state in the continuum in slab waveguide enables low-threshold quantum-dot lasing
• Super Bound States in the Continuum on Photonic Flatbands: Concept, Experimental Realization, and Optical Trapping Demonstration
• Nonreciprocal Superradiant Phase Transitions and Multicriticality in a Cavity QED System
• Bound states in the continuum in strong-coupling and weak-coupling regimes under the cylinder-ring transition
• Inherent spin-orbit locking in topological bound state in the continuum lasing