Unidirectional unpolarized luminescence emission via vortex excitation

Controlling the direction of light emission on the subwavelength scale is a key capability for quantum information processing and optical imaging in photonics and biology 1 – 5 . The spin–orbit interaction of light is widely adopted for dynamically tuning the direction of circularly polarized photoluminescence (PL), but this is challenging to accomplish for many luminescence materials, which typically generate unpolarized luminescence. Here, we report optical control of unidirectional emission of unpolarized luminescence in a spatially symmetric nanopillar lattice assisted by photonic orbital angular momenta. The orientation of anti-Stokes shift PL emissions can be controlled by the helicity of incident vortex beams. The experimental directionality of unpolarized PL emission in the one-dimensional nanopillar lattice can reach 0.59, which is markedly stronger than that possible by a spin mechanism. Our findings thus offer a new promising approach for tuneable nanoscale optical control of emission.