Spin and Orbital Angular Momentum Lasing from Phase-gradient Plasmonic Lattices

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Controlling polarization, wavefront, and directionality of lasing emission is crucial for optical technologies.
• Independent tunability of these characteristics in a single cavity remains a significant challenge.
• Dielectric metasurfaces offer wavefront control but often lack high-quality cavity modes for lasing.

Purpose of the Study:

• To demonstrate plasmonic cavities capable of supporting phase-gradient lattice resonances.
• To achieve strong coupling between excitons and chiral cavity modes for tunable lasing.
• To enable simultaneous control over spin and orbital angular momentum in laser beams.

Main Methods:

• Utilizing plasmonic cavities to support phase-gradient lattice resonances.
• Employing Cadmium Selenide (CdSe) nanoplatelets for exciton coupling.
• Engineering localized plasmons to manipulate phase singularities and geometric phase.

Main Results:

• Achieved unity circular polarization at engineered Fourier space positions.
• Demonstrated strong exciton-cavity coupling, yielding photoluminescence with near-unity chirality.
• Obtained low-threshold, simultaneous lasing from multiple beams with tunable angles.

Conclusions:

• Plasmonic cavities can support engineered phase-gradient lattice resonances for lasing.
• Strong coupling enables generation of chiral light with tunable properties.
• This work highlights the potential of localized plasmons for precise control of light angular momentum.