Advances in exploiting the degrees of freedom in nanostructured metasurface design: from 1 to 3 to more

Abstract

The unusual electromagnetic responses of nanostructured metasurfaces endow them with an ability to manipulate the four fundamental properties (amplitude, phase, polarization, and frequency) of lightwave at the subwavelength scale. Based on this, in the past several years, a lot of innovative optical elements and devices, such as metagratings, metalens, metaholograms, printings, vortex beam generators, or even their combinations, have been proposed, which have greatly empowered the advanced research and applications of metasurfaces in many fields. Behind these achievements are scientists’ continuous exploration of new physics and degrees of freedom in nanostructured metasurface design. This review will focus on the progress on the design of different nanostructured metasurfaces for lightwave manipulation, including by varying/fixing the dimensions and/or orientations of isotropic/anisotropic nanostructures, which can therefore provide various functionalities for different applications. Exploiting the design degrees of freedom of optical metasurfaces provides great flexibility in the design of multifunctional and multiplexing devices, which can be applied in anticounterfeiting, information encoding and hiding, high-density optical storage, multichannel imaging and displays, sensing, optical communications, and many other related fields.

From Lingering to Rift: Metasurface Decoupling for Near‐ and Far‐Field Functionalization

“…By manipulating light's properties with a more degree of freedom, various metasurfaces have been proposed recently to construct specific light field distribution in the near‐ and far‐field. [ 20–37 ] The near‐field is the region where light's propagation distance is much less than one wavelength, while the far‐field denotes the region in which light propagates far beyond one wavelength. [ 38 ] Enabled by dividing the metasurfaces into several segments corresponding to different functionalities, the stacking, [ 23–25 ] segmenting, [ 28 ] or interleaving metasurfaces [ 29 ] can implement the integration of the near‐ and far‐field functionalities.…”

“…DOI: 10.1002/adma.202007507 in the near-and far-field. [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] The nearfield is the region where light's propagation distance is much less than one wavelength, while the far-field denotes the region in which light propagates far beyond one wavelength. [38] Enabled by dividing the metasurfaces into several segments corresponding to different functionalities, the stacking, [23][24][25] segmenting, [28] or interleaving metasurfaces [29] can implement the integration of the near-and far-field functionalities.…”

Full‐Color Holographic Display and Encryption with Full‐Polarization Degree of Freedom

“…[6][7][8][9][10] By skillfully tailoring the subwavelength nanostructure parameters, the optical response of each unit of a metasurface can be independently and completely controlled. [11,12] Previous works have demonstrated that such artificial planar material has powerful functionalities for manipulating light wave with multiple degrees of freedom, [13][14][15][16][17][18][19] which make various applications experimentally demonstrated in visible regime. Moreover, the application scenarios of such metasurface in holographic 3D imaging and information encryption are also demonstrated.…”

Optical Singularity Built on Tiny Holes

“…focused on the design of the metasurfaces with the nanoscatterers taking different shapes, different dimensions, and various rotation angles, and reviewed the related basic and applied studies in light field manipulation including the optical vortices. [ 25 ] Chen et al. summarized the researches about the phase control of metasurfaces and the applications in wave front manipulation, holography imaging, and parallel output.…”