• Advanced Photonics
  • Vol. 4, Issue 2, 024001 (2022)
Jaekyung Kim1、†, Junhwa Seong1, Younghwan Yang1, Seong-Won Moon1, Trevon Badloe1, and Junsuk Rho1、2、3、*
Author Affiliations
  • 1Pohang University of Science and Technology, Department of Mechanical Engineering, Pohang, Republic of Korea
  • 2Pohang University of Science and Technology, Department of Chemical Engineering, Pohang, Republic of Korea
  • 3POSCO–POSTECH–RIST Center for Flat Optics and Metaphotonics, Pohang, Republic of Korea
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    DOI: 10.1117/1.AP.4.2.024001 Cite this Article
    Jaekyung Kim, Junhwa Seong, Younghwan Yang, Seong-Won Moon, Trevon Badloe, Junsuk Rho. Tunable metasurfaces towards versatile metalenses and metaholograms: a review[J]. Advanced Photonics, 2022, 4(2): 024001 Copy Citation Text show less

    Abstract

    Metasurfaces have attracted great attention due to their ability to manipulate the phase, amplitude, and polarization of light in a compact form. Tunable metasurfaces have been investigated recently through the integration with mechanically moving components and electrically tunable elements. Two interesting applications, in particular, are to vary the focal point of metalenses and to switch between holographic images. We present the recent progress on tunable metasurfaces focused on metalenses and metaholograms, including the basic working principles, advantages, and disadvantages of each working mechanism. We classify the tunable stimuli based on the light source and electrical bias, as well as others such as thermal and mechanical modulation. We conclude by summarizing the recent progress of metalenses and metaholograms, and providing our perspectives for the further development of tunable metasurfaces.

    1 Introduction

    Metasurfaces are composed of two-dimensional (2D) periodic arrays of subwavelength-scale artificial elements, called meta-atoms. They have attracted great attention due to their ability to manipulate the properties of electromagnetic waves.18 Several design methods have been proposed with various shapes and compositions of meta-atoms.8,9 The Pancharatnam–Berry (PB) phase, also called geometric phase, has been investigated using rectangular-shaped meta-atoms that impart a phase delay proportional to their rotation angle. Propagation phase has been investigated by exploiting an effective refractive index to manipulate the retardation phase by changing the volume ratio, aspect ratio, and height of meta-atoms.10,11 Resonant effects such as plasmonic resonance,1215 Mie resonance,16,17 and Fabry–Pérot resonance18,19 have also been exploited. By exploiting these resources, optical elements can be highly miniaturized and various optical applications have been implemented, such as beam splitters,2022 absorbers,2329 metalenses,30,31 metaholograms,3240 selective thermal emitters,4143 detecting devices,4446 and structural color.4752

    Copy Citation Text
    Jaekyung Kim, Junhwa Seong, Younghwan Yang, Seong-Won Moon, Trevon Badloe, Junsuk Rho. Tunable metasurfaces towards versatile metalenses and metaholograms: a review[J]. Advanced Photonics, 2022, 4(2): 024001
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