Multifunctional Metasurface Tuning by Liquid Crystals in Three Dimensions.

Optical metasurfaces present remarkable opportunities for manipulating wave propagation in unconventional ways, surpassing the capabilities of traditional optical devices. In this work, we introduce and demonstrate a multifunctional dynamic tuning of dielectric metasurfaces containing liquid crystals (LCs) through an effective three-dimensional (3D) control of the molecular orientation. We theoretically and experimentally study the spectral tuning of the electric and magnetic resonances of dielectric metasurfaces, which was enabled by rotating an external magnetic field in 3D. Our approach allows for the independent control of the electric and magnetic resonances of a metasurface, enabling multifunctional operation. The magnetic field tuning approach eliminates the need for the pre-alignment of LCs and is not limited by a finite set of directions in which the LC molecules can be oriented. Our results open new pathways for realizing dynamically reconfigurable metadevices and observing novel physical effects without the usual limitations imposed by the boundary conditions of LC cells and the external voltage.