Au film is mainly used to prepare the metal structure of the terahertz (THz) microstructure. When the metal structure is fixed, it is difficult to control the terahertz wave by using the properties of Au film. In this paper, the terahertz microstructure based on the soft magnetic FeNHf film with the high permeability is designed and fabricated on the high resistivity silicon substrate. The magnetization direction of soft magnetic film is controlled by the external magnetic field H. The THz transmission characteristics and electromagnetic resonance mode of the microstructure under the control of H in split triangular structure are systematically studied. The soft magnetic FeNHf film has the characteristic of magnetic anisotropy. Therefore, the direction of the magnetization M in FeNHf film can be controlled by the external magnetic field H to be perpendicular and parallel to the magnetic field of THz wave, respectively. The THz time domain spectroscopy system is used to test the terahertz transmis-sion characteristic of the microstructure. The finite difference time domain method is used to analyze the THz electromagnetic field distribution and modulation mechanism based on the microstructure of the FeNHf film. The experimental results show that the resonance frequency of the split triangular THz microstructure can be modulated under magnetic field. At the frequency of 1.3 THz, the tunability and modulation depth are about 5.7% and 15%, respectively.
Tunable terahertz structure based on the ferromagnetic film
First published at:Jun 15, 2020
 Shen N H, Massaouti M, Gokkavas M, et al. Optically implemented broadband blueshift switch in the terahertz regime[J]. Physical Review Letters, 2011, 106(3): 037403.
 Zhang X Y, Xing Y Y, Zhang Q, et al. High speed terahertz modulator based on the single channel AlGaN/GaN high electron mobility transistor[J]. Solid-State Electronics, 2018, 146: 9–12.
 Schurig D, Mock J J, Justice B J, et al. Metamaterial electromagnetic cloak at microwave frequencies[J]. Science, 2006, 314(5801): 977–980.
 Pendry J B. Negative refraction makes a perfect lens[J]. Physical Review Letters, 2000, 85(18): 3966–3969.
 Smith D R, Pendry J B, Wiltshire M C K. Metamaterials and negative refractive index[J]. Science, 2004, 305(5685): 788–792.
 Gu Y P, Xing Y Y, Zhang X Y, et al. Enhancement of the electromagnetic energy in the asymmetric split rings with compensated microstructures[J]. Optical and Quantum Electronics, 2018, 50(4): 168.
 Xing Y Y, Zhang X Y, Zhang Q, et al. Electromagnetic resonance in the asymmetric terahertz metamaterials with triangle microstructure[J]. Optics Communications, 2018, 415: 115–120.
 Tang Y Z, Ma W Y, Wei Y H, et al. A tunable terahertz metamaterial and its sensing performance[J]. Opto-Electronic Engineering, 2017, 44(4): 453–457.
唐雨竹, 马文英, 魏耀华, 等. 一种旋转可调的太赫兹超材料及其传感特性[J]. 光电工程, 2017, 44(4): 453–457.
 Ma C W, Ma W Y, Tan Y, et al. High Q-factor terahertz metamaterial based on analog of electromagnetically induced transparency and its sensing characteristics[J]. Opto-Electronic Engineering, 2018, 45(11): 180298.
马长伟, 马文英, 谭毅, 等. 高Q值THz类EIT超材料及传感特性研究[J]. 光电工程, 2018, 45(11): 180298.
 Chen H T, Yang H, Singh R, et al. Tuning the resonance in high-temperature superconducting terahertz metamaterials[J]. Physical Review Letters, 2010, 105(24): 247402.
 Liu C, Cao M, Xu G D, et al. Research on the property of electromagnetic wave in nanostructure based on magnetic modulation[J]. Journal of Suzhou University of Science and Technology (Natural Science), 2016, 33(2): 19–22.
刘畅, 曹明, 徐国定, 等. 基于磁调控微纳复合结构的电磁波特性研究[J]. 苏州科技学院学报(自然科学版), 2016, 33(2): 19–22.
 Zhang Y X, Qiao S, Liang S X, et al. Gbps terahertz external modulator based on a composite metamaterial with a double-channel heterostructure[J]. Nano Letters, 2015, 15(5): 3501–3506.
 Russat J, Suran G, Ouahmane H, et al. Frequency-dependent complex permeability in rare earth-substituted cobalt/nonmagnetic transition metal soft ferromagnetic amorphous thin films[J]. Journal of Applied Physics, 1993, 73(3): 1386–1389.
 Grover F W. Inductance calculations[M]. New York: Dover Publications, 2004.
the National Natural Science Foundation of China (61107093), Suzhou Key Laboratory for Low Dimensional Optoelectronic Materials and Devices (SZS201611), Jiangsu Key Disciplines of Thirteen Five-Year Plan (20168765), Natural Science Foundation of the Jiangsu Higher Education Institutions of China (19KJA140001), and the Graduate Research and Practice Innovation Project of USTS (SKCX18_Y13)
Get Citation: Zhang Qiang, Zhang Xiaoyu, Xing Yuanyuan, et al. Tunable terahertz structure based on the ferromagnetic film[J]. Opto-Electronic Engineering, 2020, 47(6): 190447.
Previous: Broadband cross-slots fractal nano-antenna and its extraordinary optical transmission characteristics
Next: Analysis of the transmission characteristics of Hank-Bessel beam in anisotropic ocean turbulence