Twisting phase and intensity of light with plasmonic metasurfaces

Yuchao Zhang,Xiaodong Yang,Jie Gao

doi:10.1038/s41598-018-23382-7

Yuchao Zhang, Xiaodong Yang + Show 1 more

Open Access

https://doi.org/10.1038/s41598-018-23382-7

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Abstract

Twisting light in both phase and intensity has recently drawn great interests in various fields related to light-matter interactions such as optical manipulation of particles and quantum entanglement of photons. Conventionally, bulky optical components are required to produce such twisted optical beams, which significantly limits their applications in integrated photonics and optical chips. Here, we design and demonstrate aluminum plasmonic metasurfaces consisting of nanoslit antennas as ultracompact beam converters to generate the focused twisted beams in both phase and intensity across the visible wavelength range. The metasurface is encoded with the combined phase profile containing the helico-conical phase function together with a Fourier transform lens based on the Pancharatnam-Berry (PB) geometric phase. It is demonstrated that the created twisted beams simultaneously possess three-dimensional (3D) spiral intensity distribution around the propagation axis and complex phase structure containing both the central vortex and the peripheral vortex string. Moreover, the twisted beam exhibits an arithmetic intensity spiral at the focal plane with the maximum photon concentration located at the leading point of the spiral. Our results show the promising potential for advancing metasurface-based integrated devices in many applications of light-matter interactions.

Highlights

Optical vortices having helical phase profiles and phase singularities have drawn considerable attention in many exciting areas related to light-matter interactions, such as quantum optics[1,2,3,4,5], high-resolution imaging[6,7], optical communications[8,9], and optical manipulation of particles[10,11,12]
By introducing the Pancharatnam-Berry geometric phase accompanied with polarization conversion[25,26,27,28,29,30,31], metasurfaces have been widely used for building on-chip wavefront shaping devices such as optical vortex generators[32,33,34,35,36], flat optical lenses[37,38,39,40,41,42] compact wave plates[43,44,45], and multiplexed holograms[46,47,48,49,50,51]
We present aluminum plasmonic metasurfaces constructed from nanoslit antenna arrays to generate HC beams with both twisted phase and intensity profiles in the visible wavelength range from 400 nm to 800 nm

Summary

Introduction

Optical vortices having helical phase profiles and phase singularities have drawn considerable attention in many exciting areas related to light-matter interactions, such as quantum optics[1,2,3,4,5], high-resolution imaging[6,7], optical communications[8,9], and optical manipulation of particles[10,11,12]. One solution for the above issue is to consider optical beams with both twisted phase and intensity profiles so that TC-independent high photon density can be realized in the focused areas. The conventional method to generate HC beam requires free-space bulky optical components including spatial light modulator and Fourier transform lens, which increases the optical system complexity and limits the photonic chip integration. We present aluminum plasmonic metasurfaces constructed from nanoslit antenna arrays to generate HC beams with both twisted phase and intensity profiles in the visible wavelength range from 400 nm to 800 nm. Our demonstrated results will provide new opportunities for realizing metasurface-based photonic devices used in various applications of light-matter interactions such as quantum information processing, optical trapping, and optical communications

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