An electric field detection device. In one embodiment, the electric field detection device includes an interferometer having a reference arm and an active arm. The reference arm comprises a first electro-optic waveguide. The active arm comprises a first electrically conductive plate, a second electrically conductive plate spaced apart from the first electrically conductive plate defining a first gap therebetween, a third electrically conductive plate disposed in the first gap and vertically extending from the first electrically conductive plate to define a T-shape structure and a second gap between the third electrically conductive plate and the second electrically conductive plate, where the second gap is substantially smaller than the first gap; and a second electro-optic waveguide disposed in the second gap and being in electrical communication with the second and third electrically conductive plates.