Controlling the degrees of freedom in metasurface designs for multi-functional optical devices

Abstract

This review discusses the control over the degrees of freedom (DOF) in the design space to develop multi-functional metasurfaces.

Realizing Colorful Holographic Mimicry by Metasurfaces

“…Metasurfaces, [14][15][16][17][18][19] an emerging 2D photonic platform made of subwavelength arrays of artificially designed scatters, have demonstrated many unique features that are unavailable in conventional materials. [17,20,21] Because of the exceptional ability to modify the phase, [14][15][16]22,23] polarization, [24][25][26] and amplitude [27][28][29][30][31][32] of reradiated light, metasurfaces have enabled a number of applications, including broadband wave-plates, [33,34] polarization rotators, [25,26] perfect absorbers, [27,35] metalenses, [36][37][38][39] plasmonic color display, [28,[40][41][42] holograms, [43][44][45][46][47] and so on.…”

“…More convenient reconfigurable metasurfaces still remain great challenges. In this work, utilizing the multiple degrees of freedom in metasurface designs, [18,19] we propose and experimentally demonstrate a holographic mimicry device for the first time, which can show different images in different surrounding circumstances. To realize such a novel function, we propose a general mathematical method, called phase matrix transformation, for achieving the fully independent phase modulation and designing the objective holographic images that we want to mimic.…”

Photoelastic plasmonic metasurfaces with ultra-large near infrared spectral tuning

“…Plasmonic metasurfaces have received a great deal of attention in photonics, due to their unique ability to abruptly change the amplitude, phase and polarization of a propagating light beam. 1–4 Through localized surface plasmon resonances, metasurfaces allow for sophisticated control over the light-matter interactions, serving as a design tool for potential applications in the fields of beam manipulation, 5 flat lenses, 6 nano-holography, 7 biosensing, 8 and color printing. 9 For future applications towards adaptive optics and tunable photonic devices, there is a strong need to reversibly control the plasmonic signals.…”

Frequency‐Coded Passive Multifunctional Elastic Metasurfaces

“…Governed by generalized Snell's law, [1] these materials modulate the wavefront by relying on gradually accumulated phase Moreover, these approaches are difficult to be scaled down to suit to microscale applications such as on-chip elastic/acoustic wave devices. [26] An alternative approach to realize multifunctionality, which is often termed as multiplexing technique in the optical community, [27,28] is to design structures whose responses are tailored for different states of the incident wave such as amplitudes, frequencies, polarizations, etc. Switching between different functionalities is then achieved by changing the state of the incident wave.…”