Unidirectional Lasing from Mirror-Coupled Dielectric Lattices

Area of Science:

• Photonics
• Materials Science
• Optics

Background:

• High-quality optical resonances are crucial for laser development.
• Achieving strong light confinement away from metal surfaces is challenging due to losses.

Purpose of the Study:

• To demonstrate a hybrid system for high-quality lattice resonances.
• To achieve unidirectional lasing using these resonances.
• To investigate the underlying physics of the observed resonances.

Main Methods:

• Fabrication of transparent dielectric nanoparticle arrays (TiO2) on a metal mirror (Ag).
• Utilizing a mirror-image model to analyze resonance formation.
• Characterizing lattice resonances and demonstrating lasing under optical pumping.

Main Results:

• Observed high-quality lattice resonances with quality factors up to 2750 in the visible spectrum.
• Demonstrated unidirectional lasing with small array sizes (100 μm × 100 μm).
• Localized enhanced electromagnetic fields within the dielectric structures, away from the metal mirror.

Conclusions:

• The hybrid dielectric-metal system effectively generates bound states in the continuum for high-quality resonances.
• This approach enables efficient unidirectional lasing with potential for broader spectral applications.
• The scheme offers simultaneous strong surface field enhancement and high quality factors.