Electric field sensor based on photonic crystal at THz waves

Subject of study . A novel THz electric field sensor, based on two-dimensional photonic crystal, is proposed. Purpose of the work . In this work, the main efforts were made to design a novel electric field sensing structure based on two-dimensional photonic crystal, by use of the unique feature of the electric-optic effect for lithium niobate (LiNbO 3 ) at the frequency range of 1.5–3.5 THz. The influence of the change of the external electric field on the band structure of the THz electric field sensing structure based on two-dimensional photonic crystal and the electric field sensing characteristics of the THz electric field sensor within the detection range of electric field intensity were researched. Method . The structure size for the THz electric field sensor is analyzed to get the optimal value by the finite element method, in order that the sensitivity is able to reach the optimal value. Main results . The optimal structure size is given, and the sensitivity of the THz electric field sensor can reach 1.21×10 −3 THz/(mv/nm), and the photonic band gaps can reach 0.10 THz, within the detection range of the electric field intensity of 100–1000 mV/nm. The relationship between the electric field intensity and the terahertz frequency of photonic band gaps is obtained within the detection range of the electric field intensity. Practical significance . The detection of an electric field by a terahertz wave is realized. The proposed THz electric field sensor provides a new electric field detection technology for the field of electric field sensing detection.