Polarization-Selective On-Chip Orbital Angular Momentum Photon Sources Enabled by Nanodiamond Emitters in Metasurface-Decorated Waveguides

This is the authors' abstract. We don't add key points for this paper.

Encoding light with orbital angular momentum (OAM) provides additional photonic degrees of freedom for optical communications, structured-light engineering, and high-dimensional information processing. However, most OAM platforms rely on externally generated light, separating photon generation from OAM conversion. Here, we demonstrate source-integrated OAM photon generators combining nanodiamond-hosted nitrogen-vacancy emitters, dielectric waveguides, and metasurface-engineered holographic gratings in a chip-scale architecture. Emission from the embedded emitters is coupled into the fundamental waveguide mode, routed on chip, and converted into free-space vortex beams with prescribed helical phase fronts. A polarization-selective four-arm architecture further enables selective generation of OAM beam pairs with topological charges of ±1 and ±2 through control of excitation polarization. Experiments demonstrate high-purity OAM emission in agreement with simulations. This platform integrates photon generation, waveguide transport, and structured-light emission, providing a scalable route toward compact OAM sources and high-dimensional integrated photonic systems.