Figure 3.

Optically tunable metasurfaces. (a) A semiconductor-based OTM achieving dynamical modulation on transmitted THz wave under different pumping conditions. Inset: SEM picture of the involved meta-atom. (b) Optically controlled EIT peak tuning achieved in a THz OTM with photoconductive silicon incorporated. (c) Illustration of ultrafast all-optical tuning of Mie-resonant mode in a GaAs involved dielectric OTM. Inset: measured transient reflectance of the metadevice and the substrate under the same optical pumping. (d) Measured field-dependent nonlinear transmission spectra of a THz OTM with VO₂ incorporated. Inset: optical image of the SRR deposited on a VO₂/sapphire substrate. (e) All-optical and high-contrast transmission switching of near-IR light in a metadevice incorporated GST nanolayer. Inset: schematics of the multilayer structure of the designed OTM. (f) An OTM realized with optically sensitive polymers for dynamic polarization manipulation of visible light. Reproduced with permissions: (a) from [36] ©2009 NGP; (b) from [37]; (c) from [38]; (d) from [39] ©2012 NGP; (e) from [40] © 2013 Wiley-VCH; (f) from [41] © 2017 NPG.