Dolphin-shaped cell circle array metasurface

Abstract

A novel dolphin-shaped cell circular array metasurface for generating local composite polarized light fields. The metasurface is a circular array-shaped micro-nano metal structure, which is composed of N (N≥3 and N is a positive integer) dolphin-shaped metal cell structures arranged in equiangular rotation to form a circular array. The dolphin-shaped metal cell binds the incident light energy to the surface of the structure, and finally generates a local focused strong field at the tip of each dolphin-shaped cell. Changing the structure factor m (m>1) can adjust the enhancement factor of the focus field; due to the dolphin Shaped metal cell itself and a circular array structure arranged at an equal angle, and can convert the incident linearly polarized light into a helical phase beam; the z-direction component of the transmitted light field E z The proportion of the intensity of the total light field E intensity decreases with the increase of the propagation distance, but with the increase of the propagation distance E z The better the phase spiral. The invention can be used as an optical tweezers and an optical angular momentum controller, and has important application value in the fields of broadband optical communication, optical imaging, nanometer manipulation and the like.

Description

technical field [0001] The invention belongs to the field of optics and optoelectronics technology, and relates to light field polarization modulation, nanometer manipulation, and surface plasmon excitation, in particular to a novel dolphin-shaped cellular circular array metasurface for generating local compound polarized light fields. Background technique [0002] When light passes through a structured material with subwavelength features, its propagation constant can depend on its polarization state, even if all its components are optically isotropic. At present, many kinds of subwavelength optical devices have been designed, which can control the polarization state of the light field, that is, the spin angular momentum. At the same time, the orbital angular momentum related to the space degree of freedom of the light field can also be adjusted. Orbital angular momentum has been identified as a useful degree of freedom to enhance the information-carrying capacity of photo...

AI Technical Summary

Problems solved by technology

However, in the existing research results, there is still insufficient research on how to control linearly polarized light into a vortex beam.

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