Elliptic perfect vortex beam generation with selective modes based on single layer metasurface in broadband near-infrared range

Abstract

Asymmetric and multiple modes of perfect vortex beams (PVBs) are of great significance in the manipulation of nanoscale biological cells. As a powerful artificial subwavelength platform, miscellaneous metasurfaces have been reported to generate PVBs. However, these reported PVBs are always symmetric, that is, only one simple annular shape in the observation plane, which cannot provide multiple modes. Here, using multi-coordinate transformation techniques (MCTT), we established the phase profile of mode-selective elliptic perfect vortex beams (MS-EPVBs) in elliptical coordinate and generated multiple modes of EPVBs with arbitrary eccentricity and orientation in broadband near-infrared range based on all-dielectric metasurface, greatly enriching the modes of PVBs. Composed of optimized half-waveplate-like silicon cylinders, the designed metasurface can freely transform the incident light into EPVBs with arbitrary eccentricity and orientation with high efficiency. Furthermore, during the mode transformation, the properties of the “perfect” and broadband were preserved. This work will find potential applications in advanced fields like biophotonics and genetic engineering.