Spin-Orbit Modal Optical Vortex Beam Shaping from Dielectric Metasurfaces

Optical information and communication technologies are essentially based on the ability to shape the light field, either at the transmission or at the reception of the optical signal. Nowadays, wavelength and polarization state are already implemented in current telecom architectures and adding the spatial structuring of the light field as a novel degree of freedom to enhance data rate is desirable. In this context, the development of optical devices to shape optical modes belonging to orthogonal basis remains challenging. Here, in the context of singular optics, this work reports on the design, fabrication, and characterization of modal optical vortex beam shaping of paraxial light in the visible domain, in the framework of the Laguerre-Gauss basis. Both the azimuthal and radial degrees of freedom are univocally shaped via optical spin-orbit interaction mediated by dielectric metasurfaces by combining the spatial modulation of amplitude, geometric phase, and dynamic phase. These results not only demonstrate the realization of new optical components, but also highlight how metasurface-based technologies can contribute to optical information processing in the classical or quantum regime.