Resonance tuning for dynamic Huygens metasurfaces

Metasurfaces with dynamic optical performance have the potential to enable a broad range of applications. We computationally investigate the potential of dielectric Huygens metasurfaces, supporting both electric and magnetic dipole resonances, as a candidate platform for dynamic tuning. The asymmetric response of the two dipole resonances to changes in geometric and material parameters, and the potential for separate control of amplitude and phase, is analyzed. A review of dynamic materials, and their promise and limitations for use in dynamic Huygens metasurfaces, is discussed. Vanadium dioxide ( V O 2 ) is recognized as a singularly interesting material, due to its variable refractive index and optical absorption in response to several stimuli. Transmitted phase modulation of ± π is computationally demonstrated as a function of decaying resonance utilizing only the first 5% of the insulator-metal transition, corresponding to a temperature change of < 10 ∘ C . As another case study utilizing asymmetric resonance tuning in response to changing incidence angle, phase modulation ( 2 π range for reflected light and > 1.5 π for transmitted light) and amplitude modulation (from R = 1 to T = 1 ) are demonstrated using a simple silicon metasurface with varying incident angle within a range of ∼ 15 ∘ on two axes. A promising implementation within a micro-electromechanical system (MEMS)-based spatial light modulator, similar to conventional digital micromirror devices, is discussed.