Lithium niobate thin film electro-optic modulator.

The linear electro-optic effect offers a valuable means to control light properties via an external electric field. Lithium niobate (LN), with its high electro-optic coefficients and broad optical transparency ranges, stands out as a prominent material for efficient electro-optic modulators. The recent advent of lithium niobate-on-insulator (LNOI) wafers has sparked renewed interest in LN for compact photonic devices. In this study, we present an electro-optic modulator utilizing a thin LN film sandwiched between top and bottom gold (Au) film electrodes, forming a Fabry-Pérot (F-P) resonator. This resonator exhibits spectral resonance shifts under an applied electric field, enabling efficient modulation of reflected light strength. The modulator achieved a 2.3 % modulation amplitude under ±10 V alternating voltage. Our approach not only presents a simpler fabrication process but also offers larger modulation amplitudes compared to previously reported metasurface based LN electro-optic modulators. Our results open up new opportunities for compact electro-optic modulators with applications in beam steering devices, dynamic holograms, and spatial light modulators, and more.