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Nonlinear difference frequency generation (DFG) is a key mechanism for realizing terahertz (THz) sources. Utilizing DFG within micro- and nano-structures circumvents phase-matching limitations while supporting device miniaturization and integrability, making it a significant area of research. Enhancing the local electric field through resonant modes in micro- and nano-structures has emerged as a promising approach to achieving efficient and tunable THz sources across a broad wavelength range. This study investigates the mechanism of DFG in high-Q-factor grating-waveguide structures for efficiently tunable THz radiation over a wide spectral range using numerical simulations based on the finite element method (COMSOL Multiphysics). Theoretical analysis reveals that modulating the positional perturbation of one of the adjacent gratings effectively doubles the grating period, causing Brillouin zone folding. This folding shifts the dispersion curve of the guided modes (GMs) within the waveguide layer above the light cone, forming a guided mode resonance (GMR) with an ultra-high Q-factor, thereby significantly enhancing THz generation across a broad spectral range. Using a cadmium sulfide (CdS) grating-waveguide structure as an example, numerical simulations demonstrate that the THz conversion efficiency reaches an order of 10⁻⁸ W⁻¹ when both fundamental frequency beams have an intensity of 100 kW/cm², which is 10⁹ times higher than the conversion efficiency of a CdS film of the same thickness. Moreover, the fundamental frequency resonance wavelength can be widely tuned by adjusting the incident angle. High-Q-factor resonance modes enable various fundamental frequency combinations by changing the incident angles of the two fundamental frequency beams, facilitating the generation of THz waves with arbitrary frequencies. This approach ultimately enables a highly efficient and tunable THz source over a wide spectral range, providing valuable insights for generating THz sources on micro- and nanophotonic platforms.
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[1] Tonouchi M 2007 Nat. Photonics 1 97
[2] Huang Y, Shen Y C, Wang J Y 2023 Engineering 22 106
[3] Koch M, Mittleman D M, Ornik J, Castro-Camus E 2023 Nat. Rev. Methods Primers 3 48
[4] Rubano A, Mou S, Marrucci L, Paparo D 2019 ACS Photonics 6 1515
[5] Li X R, Li J X, Li Y H, Ozcan A, Jarrahi M 2023 Light Sci. Appl. 12 233
[6] Lewis R A 2014 J. Phys. D: Appl. Phys. 47 374001
[7] Li H T, Lu Y L, He Z G, Jia Q K, Wang L 2016 J. Infrared, Millimeter, Terahertz Waves 37 649
[8] Li Q, Li Y D, Ding S H, Wang Q 2012 J. Infrared, Millimeter, Terahertz Waves 33 548
[9] Cao J C, Han Y J 2024 Chin. J. Lasers 51 0114001 (曹俊诚, 韩英军 2024 中国激光 51 0114001)
[10] Lai R K, Hwang J R, Norris T B, Whitaker J F 1998 Appl. Phys. Lett. 72 3100
[11] Upadhya P C, Fan W H, Burnett A, Cunningham J, Davies A G, Linfield E H, Lloyd-Hughes J, Castro-Camus E, Johnston M B, Beere H 2007 Opt. Lett. 32 2297
[12] Fan W H 2011 Chin. Opt. Lett. 9 110008
[13] Bakunov M I, Bodrov S B 2014 J. Opt. Soc. Am. B 31 2549
[14] Chai L, Niu Y, Li Y F, Hu M L, Wang Q Y 2016 Acta Phys. Sin. 65 070702 (柴路, 牛跃, 栗岩锋, 胡明列, 王清月 2016 物理学报 65 070702)
[15] Huang J G, Lu J X, Zhou W, Tong J C, Huang Z, Chu J H 2013 Acta Phys. Sin. 62 120704 (黄敬国, 陆金星, 周炜, 童劲超, 黄志明, 褚君浩 2013 物理学报 62 120704)
[16] Liu H, Xu D G, Yao J Q 2008 Acta Phys. Sin. 57 5662 (刘欢, 徐德刚, 姚建铨 2008 物理学报 57 5662)
[17] Zhong K, Yao J Q, Xu D G, Zhang H Y, Wang P 2011 Acta Phys. Sin. 60 034210 (钟凯, 姚建铨, 徐德刚, 张会云, 王鹏 2011 物理学报 60 034210)
[18] Bakunov M I, Efimenko E S, Gorelov S D, Abramovsky N A, Bodrov S B 2020 Opt. Lett. 45 3533
[19] Lu Y, Wang X, Miao L, Zuo D, Cheng Z 2010 Appl. Phys. B 103 387
[20] Tochitsky S Y, Ralph J E, Sung C, Joshi C 2005 J. Appl. Phys. 98 026101
[21] Zhong K, Yao J Q, Xu D G, Wang Z, Li Z Y, Zhang H Y, Wang P 2010 Opt. Commun. 283 3520
[22] Jiang Y, Ding Y J 2007 Appl. Phys. Lett. 91 091108
[23] Shi W, Ding Y J 2005 Opt. Lett. 30 1861
[24] Brenier A 2018 Appl. Phys. B 124 194
[25] Liu P X, Xu D G, Li J Q, Yan C, Li Z X, Wang Y Y, Yao J Q 2014 IEEE Photonics Technol. Lett. 26 494
[26] Wu F, Wu J J, Guo Z W, Jiang H T, Sun Y, Li Y H, Ren J, Chen H 2019 Phys. Rev. Appl. 12 014028
[27] Ning T Y, Li X, Zhao Y, Yin L Y, Huo Y Y, Zhao L N, Yue Q Y 2020 Opt. Express 28 34024
[28] Wu F, Qin M B, Xiao S Y 2022 J. Appl. Phys. 132 193101
[29] Wu F, Liu T T, Long Y, Xiao S Y, Chen G Y 2023 Phys. Rev. B 107 165428
[30] Wu F, Qi X, Luo M, Liu T T, Xiao S Y 2023 Phys. Rev. B 108 165404
[31] Wu F, Qi X, Qin M B, Luo M, Long Y, Wu J J, Sun Y, Jiang H T, Liu T T, Xiao S Y, Chen H 2024 Phys. Rev. B 109 085436
[32] Yan M, Sun K, Ning T Y, Zhao L N, Ren Y Y, Huo Y Y 2023 Acta Phys. Sin. 72 044202 (闫梦, 孙珂, 宁廷银, 赵丽娜, 任莹莹, 霍燕燕 2023 物理学报 72 044202)
[33] Sun K L, Wei H, Chen W J, Chen Y, Cai Y J, Qiu C W, Han Z H 2023 Phys. Rev. B 107 115415
[34] Boyd R W 2020 Nonlinear Optics (London: Academic Press)
[35] Jiang H, Han Z H 2022 J. Phys. D: Appl. Phys. 55 385106
[36] Sutherland R L 2003 Handbook of nonlinear optics (New York: Marcel Dekker)
[37] Amnon Yariv, Yeh P 1984 Optical waves in crystals (New York: Wiley)
[38] Lu J, Ding B Y, Huo Y Y, Ning T Y 2018 Opt. Commun. 415 146
[39] Liu W X, Li Y H, Jiang H T, Lai Z Q, Chen H 2013 Opt. Lett. 38 163
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