Reconfigurable metasurfaces that enable light polarization control by light

Abstract

Plasmonic metasurfaces have recently attracted much attention because of their novel characteristics with respect to light polarization and wave front control on deep-subwavelength scales. The development of metasurfaces with reconfigurable optical responses is opening new opportunities in high-capacity communications, real-time holograms and adaptive optics. Such tunable devices have been developed in the mid-infrared spectral range and operated in light intensity modulation schemes. Here we present a novel optically reconfigurable hybrid metasurface that enables polarization tuning at optical frequencies. The functionality of tuning is realized by switching the coupling conditions between the plasmonic modes and the binary isomeric states of an ethyl red switching layer upon light stimulation. We achieved more than 20° nonlinear changes in the transmitted polarization azimuth using just 4 mW of switching light power. Such design schemes and principles could be easily applied to dynamically adjust the functionalities of other metasurfaces.

Optomechanics of Chiral Dielectric Metasurfaces

“…Conversely, the polarization state of the photons addressing the device can deeply influence the mechanical resonator by shifting its resonance frequency through an optothermal spring effect. Mechanical elements have been previously conjoined with optical metamaterials to augment the functionalities provided by the bare photonic patterning; however, fast light polarization and chirality manipulation has never been addressed so far. In addition, previous reports of mechanically reconfigurable metasurfaces were based on metallic scatterers, which offer limited performances due to ohmic losses; on the contrary, in the all‐dielectric system we are relying on, optical losses are extremely weak, allowing for sharp and definite resonances originating from the high refractive index contrast between the patterned semiconductor and the surrounding (air or vacuum).…”

Lattice Collective Interaction Engineered Optical Activity in Metamaterials

“…Therefore, one may expect a similar spectral collapse in the optical activity effect from the finite metamaterial arrays as the number of constitutive metamolecules increases, and experimental results demonstrate exactly that. We used a home‐built polarimeter, consisting of a rotating superachromatic quarter‐wave plate (WP), GT polarizer, and a fiber coupled spectrometer, to analyze the polarization state of the output beams from the different arrays for the x ‐polarized incidence (whose ϕ and χ are both 0) . The dispersion properties of the quarter‐wave plate, including its retardation and optical axis azimuth variation in the studied wavelength range, have already been taken into consideration and calibrated for when we performed the polarimetric measurement.…”

“…Meanwhile the electrons are further bounded to each other by an elastic spring. Such chirally arranged electron oscillators show different response to light with different handedness, and successfully explained the chiral response from the optically active molecules that coupled with two chromophores or even some complex systems . On the other hand, Lindman proposed to use a helix to represent the chiral molecule, in which electrons are constrained to move along twisting paths.…”

“…And mimicking the mechanism in the natural chiral substances, by carefully designing metamolecules with chiral symmetry, giant optical activity with several orders of magnitude stronger than the natural materials has been achieved from metamaterials with a thickness of only a fraction of wavelength resulting from the strong field localization and enhancement of light–matter interactions . Until now, researchers have got the enhanced coupling between electric dipoles excited in different layers of metamolecules, and propose artificial helix structures or planar chiral metamaterial, i.e., chiral metasurface to get boosted electric–magnetic dipole coupling. Furthermore, higher‐order multipoles or toroidal moments in metamolecules, which were essentially difficult to achieve in natural materials, also become possible and were adopted to generate giant optical activities.…”

Metasurface zone plate for light manipulation in vectorial regime

“…Metasurfaces that are composed of subwavelength antenna arrays can be promising functional elements to replace conventional thin film-based rings of the FZP for the functional multiplicity. Subwavelength antennas develop strong EM resonances, so the transmission amplitude, phase, and polarization can be modulated by adjusting the shape and arrangement of antennas [15][16][17][18][19][20] , exhibiting many applications such as lenses [21][22][23][24] , holograms [25][26][27][28][29][30] , polarizers 17,31,32 , beam splitters 33 , optical isolators 34 , and color filters 35 . In this article, we designate FZPs in which thin film-based rings are replaced with metasurfaces as metasurface zone plates (MZPs) to distinguish them from conventional thin film-based FZPs.…”