[1] Siegel P H. Terahertz technology[J]. IEEE Transactions on Microwave Theory and Techniques, 50, 910-928(2002).

[2] Tonouchi M. Cutting-edge terahertz technology[J]. Nature Photonics, 1, 97-105(2007).

[3] Fang P P, Shi X W, Liu C et al. Single- and dual-band convertible terahertz absorber based on bulk Dirac semimetal[J]. Optics Communications, 462, 125333(2020).

[4] Zhao Y T, Wu B, Huang B J et al. Switchable broadband terahertz absorber/reflector enabled by hybrid graphene-gold metasurface[J]. Optics Express, 25, 7161-7169(2017).

[5] Wang J L, Zhang B Z, Wang X et al. Flexible dual-band band-stop metamaterials filter for the terahertz region[J]. Optical Materials Express, 7, 1656-1665(2017).

[6] Zhou X T, Yin X, Zhang T et al. Ultrabroad terahertz bandpass filter by hyperbolic metamaterial waveguide[J]. Optics Express, 23, 11657-11664(2015).

[7] Wang J J, Guo K, Guo Z Y. THz filter based on the Si microdisk array[J]. AIP Advances, 9, 045106(2019).

[8] Kaveev A K, Kropotov G I, Tsygankova E V et al. Terahertz polarization conversion with quartz waveplate sets[J]. Applied Optics, 52, B60-B69(2013).

[9] Luo S W, Lin B, Yu A L et al. Broadband tunable terahertz polarization converter based on graphene metamaterial[J]. Optics Communications, 413, 184-189(2018).

[10] Yin Z P, Zheng Q, Wang K Y et al. Tunable dual-band terahertz metalens based on stacked graphene metasurfaces[J]. Optics Communications, 429, 41-45(2018).

[11] Tian S N, Guo H M, Hu J B et al. Dielectric longitudinal bifocal metalens with adjustable intensity and high focusing efficiency[J]. Optics Express, 27, 680-688(2019).

[12] Fan F, Zhang X Z, Li S S et al. Terahertz transmission and sensing properties of microstructured PMMA tube waveguide[J]. Optics Express, 23, 27204-27212(2015).

[13] He X J, Zhang Q F, Lu G J et al. Tunable ultrasensitive terahertz sensor based on complementary graphene metamaterials[J]. RSC Advances, 6, 52212-52218(2016).

[14] Pendry J B, Holden A J, Robbins D J et al. Magnetism from conductors and enhanced nonlinear phenomena[J]. IEEE Transactions on Microwave Theory and Techniques, 47, 2075-2084(1999).

[15] Smith D R, Padilla W J, Vier D C et al. Composite medium with simultaneously negative permeability and permittivity[J]. Physical Review Letters, 84, 4184-4187(2000).

[16] Shelby R A, Smith D R, Schultz S. Experimental verification of a negative index of refraction[J]. Science, 292, 77-79(2001).

[17] Zhang Y W, Qi L M, Liu C et al. Investigation of asymmetric transmission devices based on metamaterials[J]. Chinese Journal of Quantum Electronics, 35, 385-394(2018).

[18] Landy N I, Sajuyigbe S, Mock J J et al. Perfect metamaterial absorber[J]. Physical Review Letters, 100, 207402(2008).

[19] Tao H, Landy N I, Bingham C M et al. A metamaterial absorber for the terahertz regime: Design, fabrication and characterization[J]. Optics Express, 16, 7181-7188(2008).

[20] Pan M, Huang H Z, Fan B D et al. Theoretical design of a triple-band perfect metamaterial absorber based on graphene with wide-angle insensitivity[J]. Results in Physics, 23, 104037(2021).

[21] Zhou W, Chen J, Li H et al. Progress of electromagnetic metamaterial perfect absorber based on terahertz band[J]. Laser & Optoelectronics Progress, 59, 96-108(2022).

[22] Chen H T. Interference theory of metamaterial perfect absorbers[J]. Optics Express, 20, 7165-7172(2012).

[23] Li J S, Yan D X, Sun J Z. Flexible dual-band all-graphene-dielectric terahertz absorber[J]. Optical Materials Express, 9, 2067-2075(2019).

[24] Shen N H, Massaouti M, Gokkavas M et al. Optically implemented broadband blueshift switch in the terahertz regime[J]. Physical Review Letters, 106, 037403(2011).

[25] Choi H S, Ahn J S, Jung J H et al. Mid-infrared properties of a VO2 film near the metal-insulator transition[J]. Physical Review B, 54, 4621-4628(1996).

[26] Fang H M, Tian M, Chang S Q et al. Optical absorption properties in one-dimensional graphene-based photonic crystals[J]. Chinese Journal of Quantum Electronics, 35, 589-593(2018).

[27] Tao H, Bingham C M, Strikwerda A C et al. Highly flexible wide angle of incidence terahertz metamaterial absorber: Design, fabrication, and characterization[J]. Physical Review B, 78, 241103(2008).

[28] Wang B X, Zhai X, Wang G Z et al. Design of a four-band and polarization-insensitive terahertz metamaterial absorber[J]. IEEE Photonics Journal, 7, 1-8(2014).

[29] Alaee R, Farhat M, Rockstuhl C et al. A perfect absorber made of a graphene micro-ribbon metamaterial[J]. Optics Express, 20, 28017-28024(2012).

[30] Shen X P, Cui T J. Photoexcited broadband redshift switch and strength modulation of terahertz metamaterial absorber[J]. Journal of Optics, 14, 114012(2012).

[31] Andryieuski A, Lavrinenko A V. Graphene metamaterials based tunable terahertz absorber: Effective surface conductivity approach[J]. Optics Express, 21, 9144-9155(2013).

[32] Zhao Y, Huang Q P, Cai H L et al. A broadband and switchable VO2-based perfect absorber at the THz frequency[J]. Optics Communications, 426, 443-449(2018).

[33] Zhang M, Song Z Y. Terahertz bifunctional absorber based on a graphene-spacer-vanadium dioxide-spacer-metal configuration[J]. Optics Express, 28, 11780-11788(2020).

[34] Liu G D, Zhai X, Meng H Y et al. Dirac semimetals based tunable narrowband absorber at terahertz frequencies[J]. Optics Express, 26, 11471-11480(2018).

[35] Huang X, Yang F, Gao B et al. Metamaterial absorber with independently tunable amplitude and frequency in the terahertz regime[J]. Optics Express, 27, 25902-25911(2019).

[36] Yan D X, Li J S. Tunable all-graphene-dielectric single-band terahertz wave absorber[J]. Journal of Physics D: Applied Physics, 52, 275102(2019).

[37] Chen M, Chen C, Deng S J et al. Dynamically tunable polarization-independent terahertz absorber based on bulk Dirac semimetals[J]. OSA Continuum, 2, 2477-2486(2019).

[38] Xiong H, Shen Q. A thermally and electrically dual-tunable absorber based on Dirac semimetal and strontium titanate[J]. Nanoscale, 12, 14598-14604(2020).

[39] Huang X, He W, Yang F et al. Thermally tunable metamaterial absorber based on strontium titanate in the terahertz regime[J]. Optical Materials Express, 9, 1377-1385(2019).

[40] Deng G S, Xia T Y, Jing S C et al. A tunable metamaterial absorber based on liquid crystal intended for F frequency band[J]. IEEE Antennas and Wireless Propagation Letters, 16, 2062-2065(2017).

[41] Zheng W, Li W, Chang S J. A thermally tunable terahertz metamaterial absorber[J]. Optoelectronics Letters, 11, 18-21(2015).

[42] Cheng Y Z, Gong R Z, Zhao J C. A photoexcited switchable perfect metamaterial absorber/reflector with polarization-independent and wide-angle for terahertz waves[J]. Optical Materials, 62, 28-33(2016).

[43] Wang T L, Cao M Y, Zhang H Y et al. Tunable terahertz metamaterial absorber based on Dirac semimetal films[J]. Applied Optics, 57, 9555-9561(2018).

[44] Xiong H, Peng Y H, Yang F et al. Bi-tunable terahertz absorber based on strontium titanate and Dirac semimetal[J]. Optics Express, 28, 15744-15752(2020).

[45] Zhong M, Jiang X T, Zhu X L et al. Design and fabrication of a single metal layer tunable metamaterial absorber in THz range[J]. Optics & Laser Technology, 125, 106023(2020).

[46] Xing R, Jian S S. A dual-band THz absorber based on graphene sheet and ribbons[J]. Optics & Laser Technology, 100, 129-132(2018).

[47] Bao Z Y, Wang J C, Hu Z D et al. Coordinated multi-band angle insensitive selection absorber based on graphene metamaterials[J]. Optics Express, 27, 31435-31445(2019).

[48] Meng W W, Que L C, Lv J et al. A triple-band terahertz metamaterial absorber based on buck Dirac semimetals[J]. Results in Physics, 14, 102461(2019).

[49] Xu K D, Li J X, Zhang A X et al. Tunable multi-band terahertz absorber using a single-layer square graphene ring structure with T-shaped graphene strips[J]. Optics Express, 28, 11482-11492(2020).

[50] Chen M, Sun W, Cai J J et al. Frequency-tunable terahertz absorbers based on graphene metasurface[J]. Optics Communications, 382, 144-150(2017).

[51] Zhang Y, Lv J, Que L C et al. A double-band tunable perfect terahertz metamaterial absorber based on Dirac semimetals[J]. Results in Physics, 15, 102773(2019).

[52] Wang F L, Huang S, Li L et al. Dual-band tunable perfect metamaterial absorber based on graphene[J]. Applied Optics, 57, 6916-6922(2018).

[53] Li Z X, Wang T L, Qu L F et al. Design of bi-tunable triple-band metamaterial absorber based on Dirac semimetal and vanadium dioxide[J]. Optical Materials Express, 10, 1941-1950(2020).

[54] Li W Y, Cheng Y Z. Dual-band tunable terahertz perfect metamaterial absorber based on strontium titanate(STO) resonator structure[J]. Optics Communications, 462, 125265(2020).

[55] Yin Z P, Lu Y J, Xia T Y et al. Electrically tunable terahertz dual-band metamaterial absorber based on a liquid crystal[J]. RSC Advances, 8, 4197-4203(2018).

[56] Yao G, Ling F R, Yue J et al. Dual-band tunable perfect metamaterial absorber in the THz range[J]. Optics Express, 24, 1518-1527(2016).

[57] Li J S, Sun J Z. Umbrella-shaped graphene/Si for multi-band tunable terahertz absorber[J]. Applied Physics B, 125, 183(2019).

[58] Fan C Z, Tian Y C, Ren P W et al. Realization of THz dualband absorber with periodic cross-shaped graphene metamaterials[J]. Chinese Physics B, 28, 076105(2019).

[59] Luo J, Lin Q, Wang L L et al. Ultrasensitive tunable terahertz sensor based on five-band perfect absorber with Dirac semimetal[J]. Optics Express, 27, 20165-20176(2019).

[60] Zhang B H, Qi Y P, Zhang T et al. Tunable multi-band terahertz absorber based on composite graphene structures with square ring and Jerusalem cross[J]. Results in Physics, 25, 104233(2021).

[61] Wang R X, Li L, Liu J L et al. Triple-band tunable perfect terahertz metamaterial absorber with liquid crystal[J]. Optics Express, 25, 32280-32289(2017).

[62] Xu Z C, Gao R M, Ding C F et al. Photoexited switchable metamaterial absorber at terahertz frequencies[J]. Optics Communications, 344, 125-128(2015).

[63] Jia Y L, Yin H Y, Yao H W et al. Realization of multi-band perfect absorber in graphene based metal-insulator-metal metamaterials[J]. Results in Physics, 25, 104301(2021).

[64] Zhang R Y, Luo Y H, Xu J K et al. Structured vanadium dioxide metamaterial for tunable broadband terahertz absorption[J]. Optics Express, 29, 42989-42998(2021).

[65] Song Z Y, Wang K, Li J W et al. Broadband tunable terahertz absorber based on vanadium dioxide metamaterials[J]. Optics Express, 26, 7148-7154(2018).

[66] Mou N L, Sun S L, Dong H X et al. Hybridization-induced broadband terahertz wave absorption with graphene metasurfaces[J]. Optics Express, 26, 11728-11736(2018).

[67] Wu T, Shao Y B, Ma S et al. Broadband terahertz absorber with tunable frequency and bandwidth by using Dirac semimetal and strontium titanate[J]. Optics Express, 29, 7713-7723(2021).

[68] Feng H, Xu Z X, Li K et al. Tunable polarization-independent and angle-insensitive broadband terahertz absorber with graphene metamaterials[J]. Optics Express, 29, 7158-7167(2021).

[69] Xiao B G, Gu M Y, Xiao S S. Broadband, wide-angle and tunable terahertz absorber based on cross-shaped graphene arrays[J]. Applied Optics, 56, 5458-5462(2017).

[70] Li H, Yu J. Active dual-tunable broadband absorber based on a hybrid graphene-vanadium dioxide metamaterial[J]. OSA Continuum, 3, 2143-2155(2020).

[71] Xiong H, Shen Q, Ji Q. Broadband dynamically tunable terahertz absorber based on a Dirac semimetal[J]. Applied Optics, 59, 4970-4976(2020).

[72] Xiong H, Ji Q, Bashir T et al. Dual-controlled broadband terahertz absorber based on graphene and Dirac semimetal[J]. Optics Express, 28, 13884-13894(2020).

[73] Wang S X, Cai C F, You M H et al. Vanadium dioxide based broadband THz metamaterial absorbers with high tunability: Simulation study[J]. Optics Express, 27, 19436-19447(2019).

[74] Dao R N, Kong X R, Zhang H F et al. A tunable broadband terahertz metamaterial absorber based on the vanadium dioxide[J]. Optik, 180, 619-625(2019).

[75] Bai J J, Zhang S S, Fan F et al. Tunable broadband THz absorber using vanadium dioxide metamaterials[J]. Optics Communications, 452, 292-295(2019).

[76] Ye L F, Chen Y, Cai G X et al. Broadband absorber with periodically sinusoidally-patterned graphene layer in terahertz range[J]. Optics Express, 25, 11223-11232(2017).

[77] Huang X, He W, Yang F et al. Polarization-independent and angle-insensitive broadband absorber with a target-patterned graphene layer in the terahertz regime[J]. Optics Express, 26, 25558-25566(2018).

[78] Xu J, Qin Z J, Chen M et al. Broadband tunable perfect absorber with high absorptivity based on double layer graphene[J]. Optical Materials Express, 11, 3398-3410(2021).

[79] Song Z Y, Jiang M W, Deng Y D et al. Wide-angle absorber with tunable intensity and bandwidth realized by a terahertz phase change material[J]. Optics Communications, 464, 125494(2020).

[80] Han J Z, Chen R S. Tunable broadband terahertz absorber based on a single-layer graphene metasurface[J]. Optics Express, 28, 30289-30298(2020).

[81] Huang J, Li J N, Yang Y et al. Broadband terahertz absorber with a flexible, reconfigurable performance based on hybrid-patterned vanadium dioxide metasurfaces[J]. Optics Express, 28, 17832-17840(2020).

[82] Wu G Z, Jiao X F, Wang Y D et al. Ultra-wideband tunable metamaterial perfect absorber based on vanadium dioxide[J]. Optics Express, 29, 2703-2711(2021).

[83] Li Y L, Gao W, Guo L et al. Tunable ultra-broadband terahertz perfect absorber based on vanadium oxide metamaterial[J]. Optics Express, 29, 41222-41233(2021).

[84] Huang J, Li J N, Yang Y et al. Active controllable dual broadband terahertz absorber based on hybrid metamaterials with vanadium dioxide[J]. Optics Express, 28, 7018-7027(2020).

[85] Li Z X, Wang T L, Zhang H Y et al. Tunable bifunctional metamaterial terahertz absorber based on Dirac semimetal and vanadium dioxide[J]. Superlattices and Microstructures, 155, 106921(2021).

[86] Song Z Y, Chen A P, Zhang J H. Terahertz switching between broadband absorption and narrowband absorption[J]. Optics Express, 28, 2037-2044(2020).

[87] Zhu H L, Zhang Y, Ye L F et al. Switchable and tunable terahertz metamaterial absorber with broadband and multi-band absorption[J]. Optics Express, 28, 38626-38637(2020).

[88] Zhang M, Song Z Y. Switchable terahertz metamaterial absorber with broadband absorption and multiband absorption[J]. Optics Express, 29, 21551-21561(2021).

[89] Liu Y, Huang R, Ouyang Z B. Terahertz absorber with dynamically switchable dual-broadband based on a hybrid metamaterial with vanadium dioxide and graphene[J]. Optics Express, 29, 20839-20850(2021).

[90] Chen Z, Chen J J, Tang H W et al. Dynamically switchable broadband and triple-band terahertz absorber based on a metamaterial structure with graphene[J]. Optics Express, 30, 6778-6785(2022).

[91] Yuan S, Yang R C, Xu J P et al. Photoexcited switchable single-/ dual-band terahertz metamaterial absorber[J]. Materials Research Express, 6, 075807(2019).

[92] Chen Y, Li J S. Switchable dual-band and ultra-wideband terahertz wave absorber[J]. Optical Materials Express, 11, 2197-2205(2021).

[93] Li H, Xu W H, Cui Q et al. Theoretical design of a reconfigurable broadband integrated metamaterial terahertz device[J]. Optics Express, 28, 40060-40074(2020).

[94] Ye L F, Chen X E, Zhu C H et al. Switchable broadband terahertz spatial modulators based on patterned graphene and vanadium dioxide[J]. Optics Express, 28, 33948-33958(2020).

[95] Wang T L, Zhang H Y, Zhang Y P et al. A bi-tunable switchable polarization-independent dual-band metamaterial terahertz absorber using VO2 and Dirac semimetal[J]. Results in Physics, 19, 103484(2020).

[96] Lv T T, Dong G H, Qin C H et al. Switchable dual-band to broadband terahertz metamaterial absorber incorporating a VO2 phase transition[J]. Optics Express, 29, 5437-5447(2021).

[97] Li J S, Li X J. Switchable tri-function terahertz metasurface based on polarization vanadium dioxide and photosensitive silicon[J]. Optics Express, 30, 12823-12834(2022).

[98] Wang T L, Zhang Y P, Zhang H Y et al. Dual-controlled switchable broadband terahertz absorber based on a graphene-vanadium dioxide metamaterial[J]. Optical Materials Express, 10, 369-386(2020).

[99] Li H, Yu J. Bifunctional terahertz absorber with a tunable and switchable property between broadband and dual-band[J]. Optics Express, 28, 25225-25237(2020).

[100] Zhang B H, Xu K D. Dynamically switchable terahertz absorber based on a hybrid metamaterial with vanadium dioxide and graphene[J]. Journal of the Optical Society of America B, 38, 3425-3434(2021).

[101] Zhang B H, Xu K D. Switchable and tunable bifunctional THz metamaterial absorber[J]. Journal of the Optical Society of America B, 39, A52-A60(2022).