An ultrahigh sensitivity three-dimensional electric-field sensor with barium titanate crystal waveguides

The high-speed development and applications of modern automation production, high-capacity high-speed telecommunications, and aerospace are promoting the detection and sensing of various electric fields. In this article, we investigate a three-dimensional high-frequency electric-field sensor with a barium titanate (BaTiO3) crystal film waveguide due to an extremely high electrooptic (EO) coefficient, r51 = r42. First, the dependences of the lowest electric field, namely, the sensitivity of the sensor to the electric field and the most sensitive direction, are modeled through the nonlinear EO modulation equation of the EO coefficient, r51, and birefringence, beo, with an embedded waveguide/electrode regime. Then, for the given r51/beo values, broad dependences of device sensitivities are numerically simulated with a broad design of electrodes. Thus, as a result, for a given BaTiO3 crystal thin-film having an EO coefficient value of r51 = ≥500 pm/V and an absolute beo value of ≤0.01, the lowest electric field of tens of kilovolt/m level and the electric-field direction could also be detected with a sensing length of millimeters. Meanwhile, the frequency dependence of a scattering parameter of the microwave sensor antenna, S11, is simulated and the frequency point of 2.15 GHz for the highest gain antenna is found.