Reflection type metasurface designed for high efficiency vectorial field generation.

Shiyi Wang,Qiwen Zhan

doi:10.1038/srep29626

Abstract

We propose a reflection type metal-insulator-metal (MIM) metasurface composed of hybrid nano-antennas for comprehensive spatial engineering of the properties of optical fields. The capability of such structure is illustrated in the design of a device that can be used to produce a radially polarized vectorial beam for optical needle field generation. This device consists of uniformly segmented sectors of high efficiency MIM metasurface. With each of the segment sector functioning as a local quarter-wave-plate (QWP), the device is designed to convert circularly polarized incidence into local linear polarization to create an overall radial polarization with corresponding binary phases and extremely high dynamic range amplitude modulation. The capability of such devices enables the generation of nearly arbitrarily complex optical fields that may find broad applications that transcend disciplinary boundaries.

Highlights

We propose a reflection type metal-insulator-metal (MIM) metasurface composed of hybrid nanoantennas for comprehensive spatial engineering of the properties of optical fields
A filter consisting of concentric rings with discrete amplitude and binary phase is designed to obtain extended depth of focus (DOF) with uniform axial intensity profile and high purity longitudinal polarization
To simplify the complexity of fabrication and design, we demonstrate a device with five modulation rings for optical needle field (ONF) generation with 5λDOF by following the method reported in[17] (Fig. 1(a))

Summary

Introduction

We propose a reflection type metal-insulator-metal (MIM) metasurface composed of hybrid nanoantennas for comprehensive spatial engineering of the properties of optical fields. With each of the segment sector functioning as a local quarter-wave-plate (QWP), the device is designed to convert circularly polarized incidence into local linear polarization to create an overall radial polarization with corresponding binary phases and extremely high dynamic range amplitude modulation The capability of such devices enables the generation of nearly arbitrarily complex optical fields that may find broad applications that transcend disciplinary boundaries. With a circularly polarized illumination, devices that consist of segmented MIM meta-quarter-wave-plates can be designed for high efficiency generation of spatially polarized light with phase and amplitude modulations These nano-engineered vectorial optical fields find broad potential applications, such as optical needle field (ONF) generation under high numerical aperture (NA) focusing[13]. The overall hybrid metasurface structure integrates several functions within one device, leading to a compact device for vectorial optical field engineering that may enable highly desirable solutions for optical integration

Methods

Results

Conclusion