Light Manipulation at Compact Scale via all–Dielectric Metasurfaces

Three dimensional metamaterials incur significant challenges in term of their costly and complex fabrication thus hinder their integration with photonic integrated systems. A special case of three dimensional metamaterials are metasurfaces which are patterned along the interface between two media are able to modify amplitude, phase and polarization of the incident wave. Practical examples of the metasurface-based application include flat lenses, holography, polarization converters and beam deflectors etc. A novel application of the metasurfaces is the generation of electromagnetic vortex beam carrying orbital angular momentum with helical wave front and phase singularity along the propagation axis forming the zero-intensity region. The applications of orbital angular momentum range from optical trapping, quantum optics, optical communication, optical machining and optical microscopy etc. This paper presents the numerical study of efficient and long-propagating optical vortex in the visible domain. The proposed phase gradient metasurfaces consist of cylindrical pillars, of low-loss dielectric material, which paves a way for numerous highly efficient metasurfaces-based applications.