Polarization selective beam shaping using nanoscale dielectric metasurfaces.

Boris Desiatov,Yeshaiahu Fainman,Uriel Levy,Noa Mazurski

doi:10.1364/oe.23.022611

Abstract

Metasurfaces consisting of ultrathin nanostructures are utilized to control the properties of light including its phase, amplitude and polarization. Hereby, we demonstrate the capability of such structures to perform arbitrary polarization selective beam shaping using dielectric nanoscale metasurfaces implemented in silicon. By illuminating the structure with right handed circular polarization we reconstruct a desired image. When switching the polarization into its orthogonal state, we obtain the reconstruction of a different image. This demonstration shows the potential of using dielectric metasurfaces for high efficiency beam shaping applications in general, and specifically for polarization coded beam shaping.

Highlights

Controlling the refractive index of materials at will is a prime goal of photonics research
We demonstrate the capability of a dielectric metasurface to perform arbitrary polarization selective beam shaping
In conclusion we demonstrate the design, fabrication and experimental characterization of a dielectric metasurface acting as a polarization selective computer generated hologram, and operating at near infrared wavelength of 1550 nm

Summary

Introduction

Controlling the refractive index of materials at will is a prime goal of photonics research. Such structures exhibit strong birefringence properties, known as “form birefringence”, which can be an order of magnitude higher than the birefringence of natural materials Using this property, numerous demonstrations of polarization transformations could be achieved, including for example the generation of radially and azimuthally polarized light [12,13,14,15]. Following this plethora of demonstrations, recent years brought into the forefront the concept of metallic metasurface, in which thin metallic nanostructures have been used for the purpose of controlling the properties of light [16,17,18] polarization of the incident beam, yet with limited energetic efficiency due to the ohmic loss in the metal The latter claim is true for transmission type devices. This limitation has tailored the research focus back towards dielectric metasurfaces, with several recent important demonstrations, e.g. the use of thin silicon nanoantennas for phase and polarization control [19,20,21,22,23,24,25,26,27] as well as directional light scattering and reflection [28,29]

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Conclusion