Topologically Controlled Intracavity Laser Modes Based on Pancharatnam-Berry Phase

Incorporation of a metasurface that involves spin-orbit interaction phenomenon into a laser cavity provides a route to the generation of spin-controlled intracavity modes with different topologies. By utilizing the geometric phase, Pancharatnam-Berry phase, we found a spin-enabled self-consistent cavity solution of a Nd:YAG laser with a silicon-based metasurface. Using this solution we generated a laser mode possessing spin-controlled orbital-angular momentum. Moreover, an experimental demonstration of a vectorial vortex is achieved by the coherent superposition of modes with opposite spin and orbital angular momenta. We experimentally achieved a high mode purity of ∼95% due to laser mode competition and purification. The photonic spin-orbit interaction mechanism within a laser-cavity can be implemented with multifunctional shared-aperture nanoantenna arrays to achieve multiple intracavity topologies.