High Q lithium niobate metasurfaces with transparent electrodes for efficient amplitude and phase modulation.

Lithium niobate (LN)-based metasurfaces have demonstrated remarkable potential in integrated electro-optically adjustable metadevices with the maturation of thin film LN on insulator (LNOI) technology. Here, we proposed a type of high factor tunable metasurface with etchless LN, which is electrically driven in the vertical direction by using transparent conductive film. A transmission amplitude modulation of over 60 dB at a voltage of 20 V is realized through guided mode resonances created at the LN layer with a factor of 1320.