Nano-electromechanical Tuning of Dual-Mode Resonant Dielectric Metasurfaces for Dynamic Amplitude and Phase Modulation.

Planar all-dielectric photonic crystals or metasurfaces host various resonant eigenmodes including leaky guided mode resonances (GMR) and bound states in the continuum (BIC). Engineering these resonant modes can provide new opportunities for diverse applications. Particularly, electrical control of the resonances will boost development of the applications by making them tunable. Here, we experimentally demonstrate nano-electromechanical tuning of both the GMR and the quasi-BIC modes in the telecom wavelength range. With electrostatic forces induced by a few volts, the devices achieve spectral shifts over 5 nm, absolute intensity modulation over 40%, and modulation speed exceeding 10 kHz. We also show that the interference between two resonances enables the enhancement of the phase response when two modes are overlapped in spectrum. A phase shift of 144° is experimentally observed with a bias of 4 V. Our work suggests a direct route toward optical modulators through the engineering of GMRs and quasi-BIC resonances.