[3] [3] Menikh A. Terahertz-biosensing technology: Progress, limitations, and future outlook\[J\]. Springer Ser. Chem. Sens. Biosens., 2010, 1(8): 283-295.

[4] [4] Alves F, Kearney B, Grbovic D, et al. Narrowband terahertz emitters using metamaterial films\[J\]. Opt. Express, 2012, 20(19): 21025-21032.

[5] [5] Xiao S, Wang T, Liu T, et al. Active metamaterials and metadevices: A review\[J\]. J. Phys. D: Appl. Phys., 2020, 53(50): 503002.

[6] [6] Nagel M, Richter F, Haring-Bolivar P, et al. A functionalized THz sensor for marker-free DNA analysis\[J\]. Phys. Med. Biol., 2003, 48(22): 3625.

[7] [7] Zhou H, Yang C, Hu D L, et al. Terahertz biosensing based on bi-layer metamaterial absorbers toward ultra-high sensitivity and simple fabrication\[J\]. Appl. Phys. Lett., 2019, 115(14): 143507.

[8] [8] Saadelain A S, Hameed M F O, Elkaramany E M A, et al. Highly sensitive terahertz metamaterial sensor\[J\]. IEEE Sensors J., 2019, 19(18): 7993-7999.

[9] [9] Wang J, Lang T, Hong Z, et al. Design and fabrication of a triple-band terahertz metamaterial absorber\[J\]. Nanomaterials, 2021, 11(5): 1110.

[10] [10] Abdulkarim Y, Xiao M, Awl H, et al. Simulation and lithographic fabrication of a triple band terahertz metamaterial absorber coated on flexible polyethylene terephthalate substrate\[J\]. Opt. Mater. Express, 2022, 12: 338-359.

[12] [12] Withayachumnankul W, Abbott D. Metamaterials in the terahertz regime\[J\]. IEEE Photonics J., 2009, 1(2): 99-118.