A Single‐Celled Tri‐Functional Metasurface Enabled with Triple Manipulations of Light

Abstract

Metasurfaces capable of controlling more than two types of optical properties have drawn a broad interest recently, as they can bring great flexibility and possibilities to the design of highly-integrated multifunctional devices such as simultaneous nanoprint and holograms. However, current multifunctional metasurfaces can perform only two types of optical manipulations separately. Furthermore, their supercell or multilayer design strategies would complicate both the nanostructure design and manufacturing, and are difficult to implement the miniaturization, low-cost, and multifunctionality of light integration. Herein, merely with a single-cell design approach, a tri-functional metasurface enabled with triple manipulations of light is proposed. By merging the spectrum, polarization and phase manipulations into a single metasurface, a "three-in-one" meta-device simultaneously acting as a structural-color nanoprint, a polarization-controlled grayscale meta-image displayer and a phase-modulated meta-hologram can be constructed. Specifically, the structural-color image appears right at the metasurface plane under a natural light source while the grayscale meta-image and holographic image are reconstructed by taking different optical setups as decoding keys, which can not only significantly increase the light integration but also improve the reliability of both images. The proposed metasurface represents a new paradigm in designing multifunctional meta-devices, and has promising prospects in image displays, optical storage, optical anti-counterfeiting, etc.

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.…”

“…As a result, light works for one function is actually noise for another one, which would lower down device efficiency and crosstalk between functions is unavoidable. Besides, multifunctional integration schemes based on orientation degeneracy [ 30–32 ] have not yet eliminated the coupling between functionalities due to the limited degeneracy degree of Malus's law, leading to finite step amounts of phase manipulation (2‐ or 4‐step). Combining structural color with phase manipulation is another attempt to decouple the near‐ and far‐field functionalities, [ 33–35 ] but either the near‐field structural colors generated by varied nanostructures lead to unwanted spectral amplitude modulation for the far‐field, [ 33,34 ] or the amounts of structural colors is severely limited for homogenizing the far‐field spectral amplitude, [ 35 ] thus hindering the complete decoupling.…”

“…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.…”

Multidimensional Information Encryption and Storage: When the Input Is Light

“…The multiple polarization-dependent films could altogether provide five different images corresponding to different polarization light. Similarly, a metasurface with a single-cell designed structure could also show different responses to unpolarized light, LPL and CPL by spectrum, polarization, and phase manipulations of light [ 100 ]. Three different images merged into a single metasurface, acting as a structural color nanoprint, a polarization-controlled grayscale metaimage displayer, and a phase-modulated metahologram ( Figure 5(h) ).…”

“…(i) Approaches of information encryption based on the metasurface with an independent channel of wavelength and polarization and its corresponding pattern presented under different input conditions. Reproduced with permissions: (a) from [ 92 ], Copyright 2016, American Chemical Society; (d, e) from [ 95 ], Copyright 2019, The Royal Society of Chemistry; (f) from [ 98 ], Copyright 2018, The Royal Society of Chemistry; (g) from [ 99 ], Copyright 2019, Wiley-VCH; (h) from [ 100 ], Copyright 2020, Wiley-VCH; (i) from [ 102 ], Copyright 2019, American Chemical Society.…”