Wavelength and polarization multiplexed optical vortex demultiplexer

Optical vortex beams with orbital angular momentum (OAM) have recently received considerable attention in high-speed optical communication due to their spatial orthogonality. For realizing undamaged demultiplexing, an all-dielectric multiplexed metasurface for demultiplexing wavelength-division multiplexing and polarization-division multiplexing OAM light was proposed. This OAM demultiplexer works in the near-infrared spectral region and the transmitted vortex beams carry original topological charges and phase distribution. It is worth mentioning that this demultiplexer is vastly different from previous demultiplexers, in that it not only eliminates the cumbersome process of converting vortex beams into Gaussian beams but also maintains the original property of the transmitted vortex beams. The presented demultiplexer has flexible and compact features, which are suitable for OAM communication systems. Also, the designed wavelength- and polarization-multiplexed metasurface expands the scope of metasurface compactness multifunctional photonics, which has applications in information security and anti-counterfeiting.