[1] [1] Hsu CW, Zhen B, Stone AD, Joannopoulos JD, Soljačić M. Bound states in the continuum. Nat Rev Mater. 2016;1:Article 16048.

[2] [2] Hsu CW, Zhen B, Lee J, Chua SL, Johnson SG, Joannopoulos JD, Soljačić M. Observation of trapped light within the radiation continuum. Nature. 2013;499(7457):188–191.

[3] [3] Neumann JV, Wigner E. Über merkwü rdige diskret Eigenwerte. Phys Z. 1929;30:465.

[4] [4] Friedrich H, Wintgen D. Interfering resonances and bound states in the continuum. Phys Rev A. 1985;32(6):3231–3242.

[5] [5] Marinica DC, Borisov AG, Shabanov SV. Bound states in the continuum in photonics. Phys Rev Lett. 2008;100(18):Article 183902.

[6] [6] Plotnik Y, Peleg O, Dreisow F, Heinrich M, Nolte S, Szameit A, Segev M. Experimental observation of optical bound states in the continuum. Phys Rev Lett. 2011;107(18):Article 183901.

[7] [7] Koshelev K, Bogdanov A, Kivshar Y. Engineering with bound states in the continuum. Opt Photonics News. 2020;31(1):38–45.

[8] [8] Koshelev K, Bogdanov A, Kivshar Y. Meta-optics and bound states in the continuum. Sci Bull. 2019;64(12):836–842.

[9] [9] Azzam SI, Kildishev AV. Photonic bound states in the continuum: From basics to applications. Adv Opt Mater. 2021;9(1):Article 2001469.

[10] [10] Joseph S, Pandey S, Sarkar S, Joseph J. Bound states in the continuum in resonant nanostructures: an overview of engineered materials for tailored applications. Nanophotonics. 2021;10(17):4175–4207.10.1515/nanoph-2021-0387

[11] [11] Koshelev KL, Sadrieva ZF, Shcherbakov AA, Kivshar YS, Bogdanov AA. Bound states of the continuum in photonic structures. Phys Usp. 2021.

[12] [12] Cong L, Singh R. Symmetry-protected dual bound states in the continuum in metamaterials. Adv Opt Mater. 2019;7(13):Article 1900383.

[13] [13] Koshelev K, Lepeshov S, Liu M, Bogdanov A, Kivshar Y. Asymmetric metasurfaces with high-Q resonances governed by bound states in the continuum. Phys Rev Lett. 2018;121(19):Article 193903.

[14] [14] Sadrieva Z, Frizyuk K, Petrov M, Kivshar Y, Bogdanov A. Multipolar origin of bound states in the continuum. Phys Rev B. 2019;100(11):Article 115303.

[15] [15] Zhen B, Hsu CW, Lu L, Stone AD, Soljačić M. Topological nature of optical bound states in the continuum. Phys Rev Lett. 2014;113(25):Article 257401.

[16] [16] Mermin ND. The topological theory of defects in ordered media. Rev Mod Phys. 1979;51(3):591.

[17] [17] Hwang MS, Park HG, Song Q, Kivshar Y. Advancing nanolasers. Opt Photon News. 2023;34(1):34–41.

[18] [18] Huang C, Zhang C, Xiao S, Wang Y, Fan Y, Liu Y, Zhang N, Qu G, Ji H, Han J, et al. Ultrafast control of vortex microlasers. Science. 2020;367(6481):1018–1021.10.1126/science.aba4597

[19] [19] Kodigala A, Lepetit T, Gu Q, Bahari B, Fainman Y, Kanté B. Lasing action from photonic bound states in continuum. Nature. 2017;541(7636):196–199.10.1038/nature20799

[20] [20] Ha ST, Fu YH, Emani NK, Pan Z, Bakker RM, Paniagua-Domínguez R, Kuznetsov AI. Directional lasing in resonant semiconductor nanoantenna arrays. Nat Nanotechnol. 2018;13(11):1042–1047.

[21] [21] Hwang M-S, Lee H-C, Kim K-H, Jeong K-Y, Kwon S-H, Koshelev K, Kivshar Y, Park H-G. Ultralow-threshold laser using super-bound states in the continuum. Nat Commun. 2021;12(1):4135.

[22] [22] Yang JH, Huang ZT, Maksimov DN, Pankin PS, Timofeev IV, Hong KB, Li H, Chen JW, Hsu CY, Liu YY, et al. Low-threshold bound state in the continuum lasers in hybrid lattice resonance metasurfaces. Laser Photonics Rev. 2021;15(10):Article 2100118.

[23] [23] Mekis A, Chen J, Kurland I, Fan S, Villeneuve PR, Joannopoulos J. High transmission through sharp bends in photonic crystal waveguides. Phys Rev Lett. 1996;77(18):3787.

[24] [24] Tittl A, Leitis A, Liu M, Yesilkoy F, Choi D-Y, Neshev DN, Kivshar YS, Altug H. Imaging-based molecular barcoding with pixelated dielectric metasurfaces. Science. 2018;360(6393):1105–1109.10.1126/science.aas9768

[25] [25] Leitis A, Tittl A, Liu M, Lee BH, Gu MB, Kivshar YS, Altug H. Angle-multiplexed all-dielectric metasurfaces for broadband molecular fingerprint retrieval. Sci Adv. 2019;5(5):eaaw2871.10.1126/sciadv.aaw2871

[26] [26] Yesilkoy F, Arvelo ER, Jahani Y, Liu M, Tittl A, Cevher V, Kivshar Y, Altug H. Ultrasensitive hyperspectral imaging and biodetection enabled by dielectric metasurfaces. Nat Photonics. 2019;13(6):390–396.

[27] [27] Yang Y, Peng C, Liang Y, Li Z, Noda S. Analytical perspective for bound states in the continuum in photonic crystal slabs. Phys Rev Lett. 2014;113(3):Article 037401.

[28] [28] Jin J, Yin X, Ni L, Soljačić M, Zhen B, Peng C. Topologically enabled ultrahigh-Q guided resonances robust to out-of-plane scattering. Nature. 2019;574(7779):501–504.10.1038/s41586-019-1664-7

[29] [29] Doeleman HM, Monticone F, den Hollander W, Alù A, Koenderink AF. Experimental observation of a polarization vortex at an optical bound state in the continuum. Nat Photonics. 2018;12(7):397–401.

[30] [30] Liu W, Wang B, Zhang Y, Wang J, Zhao M, Guan F, Liu X, Shi L, Zi J. Circularly polarized states spawning from bound states in the continuum. Phys Rev Lett. 2019;123(11):Article 116104.

[31] [31] Zhang Y, Chen A, Liu W, Hsu CW, Wang B, Guan F, Liu X, Shi L, Lu L, Zi J. Observation of polarization vortices in momentum space. Phys Rev Lett. 2018;120(18):Article 186103.

[32] [32] Yang Y, Yamagami Y, Yu X, Pitchappa P, Webber J, Zhang B, Fujita M, Nagatsuma T, Singh R. Terahertz topological photonics for on-chip communication. Nat Photonics. 2020;14(7):446–451.10.1038/s41566-020-0618-9

[33] [33] Xing H, Fan J, Lu D, Gao Z, Shum PP, Cong L. Terahertz metamaterials for free-space and on-chip applications: from active metadevices to topological photonic crystals. Adv Devices Instrum. 2022;2022:Article 9852503.

[34] [34] Shao ZK, Chen HZ, Wang S, Mao XR, Yang ZQ, Wang SL, Wang XX, Hu X, Ma RM. A high-performance topological bulk laser based on band-inversion-induced reflection. Nat Nanotechnol. 2020;15(1):67–72.10.1038/s41565-019-0584-x

[35] [35] Kumar A, Gupta M, Pitchappa P, Wang N, Szriftgiser P, Ducournau G, Singh R. Phototunable chip-scale topological photonics: 160 Gbps waveguide and demultiplexer for THz 6G communication. Nat Commun. 2022;13(1):5404.

[36] [36] Kang M, Mao L, Zhang S, Xiao M, Xu H, Chan CT. Merging bound states in the continuum by harnessing higher-order topological charges. Light Sci Appl. 2022;11(1):228.

[37] [37] Chen Z, Yin X, Jin J, Zheng Z, Zhang Z, Wang F, He L, Zhen B, Peng C. Observation of miniaturized bound states in the continuum with ultra-high quality factors. Sci Bull. 2022;67(4):359–366.

[38] [38] Fan J, Li Z, Xue Z, Xing H, Lu D, Xu G, Gu J, Han J, Cong L. Hybrid bound states in the continuum in terahertz metasurfaces. Opto-Electron Sci. 2023;2(4):Article 230006.

[39] [39] Ye W, Gao Y, Liu J. Singular points of polarizations in the momentum space of photonic crystal slabs. Phys Rev Lett. 2020;124(15):Article 153904.

[40] [40] Zeng Y, Hu G, Liu K, Tang Z, Qiu C-W. Dynamics of topological polarization singularity in momentum space. Phys Rev Lett. 2021;127(17):Article 176101.

[41] [41] Plum E, Fedotov V, Zheludev N. Optical activity in extrinsically chiral metamaterial. Appl Phys Lett. 2008;93(19):Article 191911.

[42] [42] Barron LD. True and false chirality and absolute asymmetric synthesis. J Am Chem Soc. 1986;108(18):5539–5542.

[43] [43] Yin X, Jin J, Soljačić M, Peng C, Zhen B. Observation of topologically enabled unidirectional guided resonances. Nature. 2020;580(7804):467–471.10.1038/s41586-020-2181-4

[44] [44] Yin X, Peng C. Manipulating light radiation from a topological perspective. Photonics Res. 2020;8(11):B25–B38.10.1364/PRJ.403444

[45] [45] Khanikaev AB, Shvets G. Two-dimensional topological photonics. Nat Photonics. 2017;11(12):763–773.10.1038/s41566-017-0048-5

[46] [46] Kim M, Jacob Z, Rho J. Recent advances in 2D, 3D and higher-order topological photonics. Light Sci Appl. 2020;9:130.10.1038/s41377-020-0331-y

[47] [47] Wu LH, Hu X. Scheme for achieving a topological photonic crystal by using dielectric material. Phys Rev Lett. 2015;114(22):Article 223901.

[48] [48] Zhang Z, Lan Z, Xie Y, Chen ML, Wei E, Xu Y. Bound topological edge state in the continuum for all-dielectric photonic crystals. Phys Rev Appl. 2021;16(6):Article 064036.

[49] [49] Huang L, Zhang W, Zhang X. Moiré quasibound states in the continuum. Phys Rev Lett. 2022;128(25):Article 253901.

[50] [50] Longhi S, Valle GD. Floquet bound states in the continuum. Sci Rep. 2013;3:Article 2219.

[51] [51] Li C, Kartashov YV, Konotop VV. Topological Floquet bound states in the continuum. Opt Lett. 2022;47(19):5160–5163.

[52] [52] Benalcazar WA, Cerjan A. Bound states in the continuum of higher-order topological insulators. Phys Rev B. 2020;101(16):Article 161116.

[53] [53] Cerjan A, Jürgensen M, Benalcazar WA, Mukherjee S, Rechtsman MC. Observation of a higher-order topological bound state in the continuum. Phys Rev Lett. 2020;125(21):Article 213901.

[54] [54] Hu Z, Bongiovanni D, Jukić D, Jajtić E, Xia S, Song D, Xu J, Morandotti R, Buljan H, Chen Z. Nonlinear control of photonic higher-order topological bound states in the continuum. Light Sci Appl. 2021;10:Article 164.

[55] [55] Maczewsky LJ, Heinrich M, Kremer M, Ivanov SK, Ehrhardt M, Martinez F, Kartashov YV, Konotop VV, Torner L, Bauer D, et al. Nonlinearity-induced photonic topological insulator. Science. 2020;370(6517):701–704.10.1126/science.abd2033

[56] [56] Kirsch MS, Zhang Y, Kremer M, Maczewsky LJ, Ivanov SK, Kartashov YV, Torner L, Bauer D, Szameit A, Heinrich M. Nonlinear second-order photonic topological insulators. Nat Phys. 2021;17(9):995–1000.10.1038/s41567-021-01275-3

[57] [57] Weidemann S, Kremer M, Helbig T, Hofmann T, Stegmaier A, Greiter M, Thomale R, Szameit A. Topological funneling of light. Science. 2020;368(6488):311–314.10.1126/science.aaz8727

[58] [58] Hu B, Zhang Z, Zhang H, Zheng L, Xiong W, Yue Z, Wang X, Xu J, Cheng Y, Liu X, et al. Non-Hermitian topological whispering gallery. Nature. 2021;597(7878):655–659.10.1038/s41586-021-03833-4

[59] [59] Li G, Zheng Y, Dutt A, Yu D, Shan Q, Liu S, Yuan L, Fan S, Chen X. Dynamic band structure measurement in the synthetic space. Sci Adv. 2021;7(2):Article eabe4335.

[60] [60] Minkov M, Williamson IA, Xiao M, Fan S. Zero-index bound states in the continuum. Phys Rev Lett. 2018;121(26):Article 263901.

[61] [61] Dong T, Liang J, Camayd-Muñoz S, Liu Y, Tang H, Kita S, Chen P, Wu X, Chu W, Mazur E, et al. Ultra-low-loss on-chip zero-index materials. Light Sci Appl. 2021;10:Article 10.

[62] [62] Yu N, Genevet P, Kats MA, Aieta F, Tetienne J-P, Capasso F, Gaburro Z. Light propagation with phase discontinuities: Generalized laws of reflection and refraction. Science. 2011;334(6054):333–337.10.1126/science.1210713

[63] [63] Khorasaninejad M, Chen WT, Devlin RC, Oh J, Zhu AY, Capasso F. Metalenses at visible wavelengths: Diffraction-limited focusing and subwavelength resolution imaging. Science. 2016;352(6290):1190–1194.10.1126/science.aaf6644

[64] [64] Wang S, Wu PC, Su V-C, Lai Y-C, Hung Chu C, Chen J-W, Lu S-H, Chen J, Xu B, Kuan C-H. Broadband achromatic optical metasurface devices. Nat Commun. 2017;8(1):187.

[65] [65] Overvig A, Alù A. Diffractive nonlocal metasurfaces. Laser Photonics Rev. 2022;16(8):Article 2100633.

[66] [66] Chen R, Wang S. Versatile platform of nonlocal metasurfaces for both spectral and spatial control of light waves. Light Sci Appl. 2022;11(1):295.

[67] [67] Malek SC, Overvig AC, Alù A, Yu N. Resonant wavefront-shaping flat optics. arXiv. 2020. 10.48550/arXiv.2009.07054

[68] [68] Cong L, Pitchappa P, Lee C, Singh R. Active phase transition via loss engineering in a terahertz MEMS metamaterial. Adv Mater. 2017;29(26):Article 1700733.

[69] [69] Cong L, Pitchappa P, Wu Y, Ke L, Lee C, Singh N, Yang H, Singh R. Active multifunctional microelectromechanical system metadevices: Applications in polarization control, wavefront deflection, and holograms. Adv Opt Mater. 2017;5(2):Article 1600716.

[70] [70] Cong L, Srivastava YK, Zhang H, Zhang X, Han J, Singh R. All-optical active THz metasurfaces for ultrafast polarization switching and dynamic beam splitting. Light Sci Appl. 2018;7(1):Article 28.

[71] [71] Fan S, Suh W, Joannopoulos JD. Temporal coupled-mode theory for the Fano resonance in optical resonators. J Opt Soc Am A. 2003;20(3):569–572.

[72] [72] Kwon H, Sounas D, Cordaro A, Polman A, Alù A. Nonlocal metasurfaces for optical signal processing. Phys Rev Lett. 2018;121(17):Article 173004.

[73] [73] Song J-H, van de Groep J, Kim SJ, Brongersma ML. Non-local metasurfaces for spectrally decoupled wavefront manipulation and eye tracking. Nat Nanotechnol. 2021;16(11):1224–1230.10.1038/s41565-021-00967-4

[74] [74] Koshelev K, Kruk S, Melik-Gaykazyan E, Choi J-H, Bogdanov A, Park H-G, Kivshar Y. Subwavelength dielectric resonators for nonlinear nanophotonics. Science. 2020;367(6475):288–292.10.1126/science.aaz3985

[75] [75] Koshelev K, Tang Y, Li K, Choi DY, Li G, Kivshar Y. Nonlinear metasurfaces governed by bound states in the continuum. ACS Photonics. 2019;6(7):1639–1644.

[76] [76] Overvig AC, Malek SC, Yu N. Multifunctional nonlocal metasurfaces. Phys Rev Lett. 2020;125(1):Article 017402.

[77] [77] Overvig AC, Malek SC, Carter MJ, Shrestha S, Yu N. Selection rules for quasibound states in the continuum. Phys Rev B. 2020;102(3):Article 035434.

[78] [78] Nguyen HS, Dubois F, Deschamps T, Cueff S, Pardon A, Leclercq JL, Seassal C, Letartre X, Viktorovitch P. Symmetry breaking in photonic crystals: On-demand dispersion from flatband to Dirac cones. Phys Rev Lett. 2018;120(6):Article 066102.

[79] [79] Malek SC, Overvig AC, Alu A, Yu N. Multifunctional resonant wavefront-shaping meta-optics based on multilayer and multi-perturbation nonlocal metasurfaces. Light Sci Appl. 2022;11(1):246.

[80] [80] Lan S, Zhang X, Taghinejad M, Rodrigues S, Lee K-T, Liu Z, Cai W. Metasurfaces for near-eye augmented reality. ACS Photonics. 2019;6(4):864–870.10.1021/acsphotonics.9b00180

[81] [81] Overvig AC, Mann SA, Alù A. Thermal metasurfaces: complete emission control by combining local and nonlocal light-matter interactions. Phys Rev X. 2021;11(2):Article 021050.

[82] [82] Overvig A, Alù A. Wavefront-selective Fano resonant metasurfaces. Adv Photonics. 2021;3(2):Article 026002.

[83] [83] Qiu CW, Zhang T, Hu G, Kivshar Y. Quo vadis, metasurfaces? Nano Lett. 2021;21(13):5461–5474.10.1021/acs.nanolett.1c00828

[84] [84] Krasnok A, Tymchenko M, Alù A. Nonlinear metasurfaces: a paradigm shift in nonlinear optics. Mater Today. 2018;21(1):8–21.10.1016/j.mattod.2017.06.007

[85] [85] Li G, Zhang S, Zentgraf T. Nonlinear photonic metasurfaces. Nat Rev Mater. 2017;2(5):Article 17010.

[86] [86] Overvig A, Yu N, Alù A. Chiral quasi-bound states in the continuum. Phys Rev Lett. 2021;126(7):Article 073001.

[87] [87] Chen Y, Gao J, Yang X. Chiral metamaterials of plasmonic slanted nanoapertures with symmetry breaking. Nano Lett. 2018;18(1):520–527.10.1021/acs.nanolett.7b04515

[88] [88] Valev VK, Baumberg JJ, Sibilia C, Verbiest T. Chirality and chiroptical effects in plasmonic nanostructures: Fundamentals, recent progress, and outlook. Adv Mater. 2013;25(18):2517–2534.10.1002/adma.201205178

[89] [89] Mun J, Kim M, Yang Y, Badloe T, Ni J, Chen Y, Qiu C-W, Rho J. Electromagnetic chirality: from fundamentals to nontraditional chiroptical phenomena. Light Sci Appl. 2020;9(1):139.

[90] [90] Gansel JK, Thiel M, Rill MS, Decker M, Bade K, Saile V, von Freymann G, Linden S, Wegener M. Gold helix photonic metamaterial as broadband circular polarizer. Science. 2009;325(5947):1513–1515.10.1126/science.1177031

[91] [91] Mark AG, Gibbs JG, Lee T-C, Fischer P. Hybrid nanocolloids with programmed three-dimensional shape and material composition. Nat Mater. 2013;12(9):802–807.10.1038/nmat3685

[92] [92] Fan J, Xiao D, Lei T, Yuan X. Incidence angle-dependent broadband chiral metamaterial for near-infrared light absorption. J Opt Soc Am B. 2020;37(11):3422–3428.

[93] [93] Khanikaev AB, Arju N, Fan Z, Purtseladze D, Lu F, Lee J, Sarriugarte P, Schnell M, Hillenbrand R, Belkin M. Experimental demonstration of the microscopic origin of circular dichroism in two-dimensional metamaterials. Nat Commun. 2016;7:Article 12045.

[94] [94] Cong L, Pitchappa P, Wang N, Singh R. Electrically programmable terahertz diatomic metamolecules for chiral optical control. Research. 2019;2019:Article 7084251.

[95] [95] Zhou J, Dong J, Wang B, Koschny T, Kafesaki M, Soukoulis CM. Negative refractive index due to chirality. Phys Rev B. 2009;79(12):Article 121104.

[96] [96] Decker M, Ruther M, Kriegler C, Zhou J, Soukoulis C, Linden S, Wegener M. Strong optical activity from twisted-cross photonic metamaterials. Opt Lett. 2009;34(16):2501–2503.10.1364/OL.34.002501

[97] [97] Wang Z, Jia H, Yao K, Cai W, Chen H, Liu Y. Circular dichroism metamirrors with near-perfect extinction. ACS Photonics. 2016;3(11):2096–2101.10.1021/acsphotonics.6b00533

[98] [98] Zhang X, Liu Y, Han J, Kivshar Y, Song Q. Chiral emission from resonant metasurfaces. Science. 2022;377(6611):1215–1218.10.1126/science.abq7870

[99] [99] Wei J, Chen Y, Li Y, Li W, Xie J, Lee C, Novoselov KS, Qiu C-W. Geometric filterless photodetectors for mid-infrared spin light. Nat Photonics. 2023;17:171–178.10.1038/s41566-022-01115-7

[100] [100] Cao T, Mao L, Qiu Y, Lu L, Banas A, Banas K, Simpson RE, Chui HC. Fano resonance in asymmetric plasmonic nanostructure: separation of sub-10 nm enantiomers. Adv Opt Mater. 2019;7(3):Article 1801172.

[101] [101] Gorkunov MV, Antonov AA, Kivshar YS. Metasurfaces with maximum chirality empowered by bound states in the continuum. Phys Rev Lett. 2020;125(9):Article 093903.

[102] [102] Gorkunov MV, Antonov AA, Tuz VR, Kupriianov AS, Kivshar YS. Bound states in the continuum underpin near-lossless maximum chirality in dielectric metasurfaces. Adv Opt Mater. 2021;9(19):Article 2100797.

[103] [103] Chen Y, Deng H, Sha X, Chen W, Wang R, Chen Y, Wu D, Chu J, Kivshar YS, Xiao S, et al. Observation of intrinsic chiral bound states in the continuum. Nature. 2023;613(7944):474–478.10.1038/s41586-022-05467-6

[104] [104] Kühner L, Wendisch FJ, Antonov AA, Bürger J, Hüttenhofer L, Menezes LdS, Maier SA, Gorkunov MV, Kivshar Y, Tittl A. Unlocking the out-of-plane dimension for photonic bound states in the continuum to achieve maximum optical chirality. arXiv. 2022. 10.48550/arXiv.2210.05339

[105] [105] Shi T, Deng ZL, Geng G, Zeng X, Zeng Y, Hu G, Overvig A, Li J, Qiu CW, Alu A, et al. Planar chiral metasurfaces with maximal and tunable chiroptical response driven by bound states in the continuum. Nat Commun. 2022;13(1):Article 4111.

[106] [106] Shen Z, Fang X, Li S, Yin W, Zhang L, Chen X. Terahertz spin-selective perfect absorption enabled by quasi-bound states in the continuum. Opt Lett. 2022;47(3):505–508.

[107] [107] Wang J, Shi L, Zi J. Spin hall effect of light via momentum-space topological vortices around bound states in the continuum. Phys Rev Lett. 2022;129(23):Article 236101.

[108] [108] Iwahashi S, Kurosaka Y, Sakai K, Kitamura K, Takayama N, Noda S. Higher-order vector beams produced by photonic-crystal lasers. Opt Express. 2011;19(13):11963–11968.

[109] [109] Wang B, Liu W, Zhao M, Wang J, Zhang Y, Chen A, Guan F, Liu X, Shi L, Zi J. Generating optical vortex beams by momentum-space polarization vortices centred at bound states in the continuum. Nat Photonics. 2020;14(10):623–628.10.1038/s41566-020-0658-1

[110] [110] Liu H, Guo C, Vampa G, Zhang JL, Sarmiento T, Xiao M, Bucksbaum PH, Vučković J, Fan S, Reis DA. Enhanced high-harmonic generation from an all-dielectric metasurface. Nat Phys. 2018;14(10):1006–1010.10.1038/s41567-018-0233-6

[111] [111] McDonnell C, Deng J, Sideris S, Ellenbogen T, Li G. Functional THz emitters based on Pancharatnam-Berry phase nonlinear metasurfaces. Nat Commun. 2021;12(1):30.

[112] [112] Carletti L, Koshelev K, De Angelis C, Kivshar Y. Giant nonlinear response at the nanoscale driven by bound states in the continuum. Phys Rev Lett. 2018;121(3):Article 033903.

[113] [113] Volkovskaya I, Xu L, Huang L, Smirnov AI, Miroshnichenko AE, Smirnova D. Multipolar second-harmonic generation from high-Q quasi-BIC states in subwavelength resonators. Nanophotonics. 2020;9(12):3953–3963.10.1515/nanoph-2020-0156

[114] [114] Ning T, Li X, Zhang Z, Huo Y, Yue Q, Zhao L, Gao Y. Ultimate conversion efficiency of second harmonic generation in all-dielectric resonators of quasi-BICs in consideration of nonlinear refraction of dielectrics. Opt Express. 2021;29(11):17286–17294.10.1364/OE.427355

[115] [115] Han Z, Ding F, Cai Y, Levy U. Significantly enhanced second-harmonic generations with all-dielectric antenna array working in the quasi-bound states in the continuum and excited by linearly polarized plane waves. Nanophotonics. 2021;10(3):1189–1196.10.1515/nanoph-2020-0598

[116] [116] Anthur AP, Zhang H, Paniagua-Dominguez R, Kalashnikov DA, Ha ST, Mass TWW, Kuznetsov AI, Krivitsky L. Continuous wave second harmonic generation enabled by quasi-bound-states in the continuum on gallium phosphide metasurfaces. Nano Lett. 2020;20(12):8745–8751.10.1021/acs.nanolett.0c03601

[117] [117] Khmelevskaia D, Markina DI, Fedorov VV, Ermolaev GA, Arsenin AV, Volkov VS, Goltaev AS, Zadiranov YM, Tzibizov IA, Pushkarev AP, et al. Directly grown crystalline gallium phosphide on sapphire for nonlinear all-dielectric nanophotonics. Appl Phys Lett. 2021;118(20):Article 201101.

[118] [118] Löchner FJF, Fedotova AN, Liu S, Keeler GA, Peake GM, Saravi S, Shcherbakov MR, Burger S, Fedyanin AA, Brener I, et al. Polarization-dependent second harmonic diffraction from resonant GaAs metasurfaces. ACS Photonics. 2018;5(5):1786–1793.

[119] [119] Vabishchevich PP, Liu S, Sinclair MB, Keeler GA, Peake GM, Brener I. Enhanced second-harmonic generation using broken symmetry III–V semiconductor fano metasurfaces. ACS Photonics. 2018;5(5):1685–1690.

[120] [120] Zhu D, Shao L, Yu M, Cheng R, Desiatov B, Xin CJ, Hu Y, Holzgrafe J, Ghosh S, Shams-Ansari A, et al. Integrated photonics on thin-film lithium niobate. Adv Opt Photon. 2021;13(2):242–352.10.1364/AOP.411024

[121] [121] Zheng Z, Xu L, Huang L, Smirnova D, Hong P, Ying C, Rahmani M. Boosting second-harmonic generation in the LiNbO3 metasurface using high-Q guided resonances and bound states in the continuum. Phys Rev B. 2022;106(12):Article 125411.

[122] [122] Zhang X, He L, Gan X, Huang X, Du Y, Zhai Z, Li Z, Zheng Y, Chen X, Cai Y, et al. Quasi-bound states in the continuum enhanced second-harmonic generation in thin-film lithium niobate. Laser Photonics Rev. 2022;16(9):Article 2200031.

[123] [123] Kühner L, Sortino L, Tilmann B, Weber T, Watanabe K, Taniguchi T, Maier SA, Tittl A. High-Q nanophotonics over the full visible spectrum enabled by hexagonal boron nitride metasurfaces. Adv Mater. 2023;35(13):Article 2209688.

[124] [124] Fang C, Yang Q, Yuan Q, Gu L, Gan X, Shao Y, Liu Y, Han G, Hao Y. Efficient second-harmonic generation from silicon slotted nanocubes with bound states in the continuum. Laser Photonics Rev. 2022;16(5):Article 2100498.

[125] [125] Zograf G, Koshelev K, Zalogina A, Korolev V, Hollinger R, Choi D-Y, Zuerch M, Spielmann C, Luther-Davies B, Kartashov D, et al. High-harmonic generation from resonant dielectric metasurfaces empowered by bound states in the continuum. ACS Photonics. 2022;9(2):567–574.10.1021/acsphotonics.1c01511

[126] [126] Carletti L, Kruk SS, Bogdanov AA, De Angelis C, Kivshar Y. High-harmonic generation at the nanoscale boosted by bound states in the continuum. Phys Rev Res. 2019;1(2):Article 023016.

[127] [127] Liu Z, Xu Y, Lin Y, Xiang J, Feng T, Cao Q, Li J, Lan S, Liu J. High-Q quasibound states in the continuum for nonlinear metasurfaces. Phys Rev Lett. 2019;123(25):Article 253901.

[128] [128] Sinev IS, Koshelev K, Liu Z, Rudenko A, Ladutenko K, Shcherbakov A, Sadrieva Z, Baranov M, Itina T, Liu J, et al. Observation of ultrafast self-action effects in quasi-BIC resonant metasurfaces. Nano Lett. 2021;21(20):8848–8855.

[129] [129] Yang G, Dev SU, Allen MS, Allen JW, Harutyunyan H. Optical bound states in the continuum enabled by magnetic resonances coupled to a mirror. Nano Lett. 2022;22(5):2001–2008.10.1021/acs.nanolett.1c04764

[130] [130] Camacho-Morales R, Xu L, Zhang H, Ha ST, Krivitsky L, Kuznetsov AI, Rahmani M, Neshev D. Sum-frequency generation in high-Q GaP metasurfaces driven by leaky-wave guided modes. Nano Lett. 2022;22(15):6141–6148.

[131] [131] Hu L, Wang B, Guo Y, Du S, Chen J, Li J, Gu C, Wang L. Quasi-BIC enhanced broadband terahertz generation in all-dielectric metasurface. Adv Opt Mater. 2022;10(12):Article 2200193.

[132] [132] Tu Y, Sun X, Wu H, Zan X, Yang Y, Liu N, Wang X, Meng C, Lyu Z, Zhu Z, et al. Enhanced terahertz generation from the lithium niobate metasurface. Front Phys. 2022;10:Article 883703.

[133] [133] Luo L, Chatzakis I, Wang J, Niesler FB, Wegener M, Koschny T, Soukoulis CM. Broadband terahertz generation from metamaterials. Nat Commun. 2014;5:Article 3055.

[134] [134] McDonnell C, Deng J, Sideris S, Li G, Ellenbogen T. Terahertz metagrating emitters with beam steering and full linear polarization control. Nano Lett. 2022;22(7):2603–2610.

[135] [135] Lu Y, Feng X, Wang Q, Zhang X, Fang M, Sha WEI, Huang Z, Xu Q, Niu L, Chen X, et al. Integrated terahertz generator-manipulators using epsilon-near-zero-hybrid nonlinear metasurfaces. Nano Lett. 2021;21(18):7699–7707.10.1021/acs.nanolett.1c02372

[136] [136] Liu Z, Wang J, Chen B, Wei Y, Liu W, Liu J. Giant enhancement of continuous wave second harmonic generation from few-layer GaSe coupled to High-Q quasi bound states in the continuum. Nano Lett. 2021;21(17):7405–7410.10.1021/acs.nanolett.1c01975

[137] [137] Wang T, Zhang S. Large enhancement of second harmonic generation from transition-metal dichalcogenide monolayer on grating near bound states in the continuum. Opt Express. 2018;26(1):322–337.

[138] [138] Liu Y, Zhu S, Zhou Q, Cao Y, Fu Y, Gao L, Chen H, Xu Y. Enhanced third-harmonic generation induced by nonlinear field resonances in plasmonic-graphene metasurfaces. Opt Express. 2020;28(9):13234–13242.10.1364/OE.391294

[139] [139] Bernhardt N, Koshelev K, White SJU, Meng KWC, Froch JE, Kim S, Tran TT, Choi DY, Kivshar Y, Solntsev AS. Quasi-BIC resonant enhancement of second-harmonic generation in WS2 monolayers. Nano Lett. 2020;20(7):5309–5314.10.1021/acs.nanolett.0c01603

[140] [140] Löchner FJF, George A, Koshelev K, Bucher T, Najafidehaghani E, Fedotova A, Choi D-Y, Pertsch T, Staude I, Kivshar Y, et al. Hybrid dielectric metasurfaces for enhancing second-harmonic generation in chemical vapor deposition grown MoS2 monolayers. ACS Photonics. 2021;8(1):218–227.10.1021/acsphotonics.0c01375

[141] [141] Hong P, Xu L, Rahmani M. Dual bound states in the continuum enhanced second harmonic generation with transition metal dichalcogenides monolayer. Opto-Electron Adv. 2022;5(7):Article 200097.

[142] [142] Wang J, Clementi M, Minkov M, Barone A, Carlin J-F, Grandjean N, Gerace D, Fan S, Galli M, Houdré R. Doubly resonant second-harmonic generation of a vortex beam from a bound state in the continuum. Optica. 2020;7(9):1126–1132.10.1364/OPTICA.396408

[143] [143] Mobini E, Alaee R, Boyd RW, Dolgaleva K. Giant asymmetric second-harmonic generation in bianisotropic metasurfaces based on bound states in the continuum. ACS Photonics. 2021;8(11):3234–3240.

[144] [144] Xiao S, Qin M, Duan J, Wu F, Liu T. Polarization-controlled dynamically switchable high-harmonic generation from all-dielectric metasurfaces governed by dual bound states in the continuum. Phys Rev B. 2022;105(19):Article 195440.

[145] [145] Xu L, Zangeneh Kamali K, Huang L, Rahmani M, Smirnov A, Camacho-Morales R, Ma Y, Zhang G, Woolley M, Neshev D, et al. Dynamic nonlinear image tuning through magnetic dipole quasi-BIC ultrathin resonators. Adv Sci. 2019;6(15):Article 1802119.

[146] [146] Liu Q, Cheng B, Chao M, Zhang W, Xu Y, Song G. Giant nonlinear circular dichroism from high Q-factor asymmetric lithium niobate metasurfaces. Ann Phys. 2021;533(11):Article 2100255.

[147] [147] Kruk SS, Wang L, Sain B, Dong Z, Yang J, Zentgraf T, Kivshar Y. Asymmetric parametric generation of images with nonlinear dielectric metasurfaces. Nat Photonics. 2022;16(8):561–565.10.1038/s41566-022-01018-7

[148] [148] Baranov DG, Zuev DA, Lepeshov SI, Kotov OV, Krasnok AE, Evlyukhin AB, Chichkov BN. All-dielectric nanophotonics: The quest for better materials and fabrication techniques. Optica. 2017;4(7):814–825.

[149] [149] Yang Q, Liu Y, Gan X, Fang C, Han G, Hao Y. Nonlinear bound states in the continuum of etchless lithium niobate metasurfaces. IEEE Photonics J. 2020;12(5):1–9.10.1109/JPHOT.2020.3024789

[150] [150] Huang Z, Luo K, Feng Z, Zhang Z, Li Y, Qiu W, Guan H, Xu Y, Li X, Lu H. Resonant enhancement of second harmonic generation in etchless thin film lithium niobate heteronanostructure. Sci China Phys Mech Astron. 2022;65(10):Article 104211.

[151] [151] Aigner A, Tittl A, Wang J, Weber T, Kivshar Y, Maier SA, Ren H. Plasmonic bound states in the continuum to tailor light-matter coupling. Sci Adv. 2022;8(49):Article eadd4816.

[152] [152] Cong L, Tan S, Yahiaoui R, Yan F, Zhang W, Singh R. Experimental demonstration of ultrasensitive sensing with terahertz metamaterial absorbers: A comparison with the metasurfaces. Appl Phys Lett. 2015;106(3):Article 031107.

[153] [153] Cong L, Manjappa M, Xu N, Al-Naib I, Zhang W, Singh R. Fano resonances in terahertz metasurfaces: a figure of merit optimization. Adv Opt Mater. 2015;3(11):1537–1543.10.1002/adom.201500207

[154] [154] Romano S, Zito G, Torino S, Calafiore G, Penzo E, Coppola G, Cabrini S, Rendina I, Mocella V. Label-free sensing of ultralow-weight molecules with all-dielectric metasurfaces supporting bound states in the continuum. Photonics Res. 2018;6(7):726–733.

[155] [155] Singh R, Cao W, Al-Naib I, Cong L, Withayachumnankul W, Zhang W. Ultrasensitive terahertz sensing with high-Q Fano resonances in metasurfaces. Appl Phys Lett. 2014;105(17):Article 171101.

[156] [156] Romano S, Zito G, Managò S, Calafiore G, Penzo E, Cabrini S, De Luca AC, Mocella V. Surface-enhanced raman and fluorescence spectroscopy with an all-dielectric metasurface. J Phys Chem C. 2018;122(34):19738–19745.

[157] [157] Hill MT, Gather MC. Advances in small lasers. Nat Photonics. 2014;8(12):908–918.10.1038/nphoton.2014.239

[158] [158] Ma R-M, Oulton RF. Applications of nanolasers. Nat Nanotechnol. 2019;14(1):12–22.10.1038/s41565-018-0320-y

[159] [159] Bahari B, Vallini F, Lepetit T, Tellez-Limon R, Park J, Kodigala A, Fainman Y, Kante B. Integrated and steerable vortex lasers using bound states in continuum. arXiv. 2017. 10.48550/arXiv.1707.00181

[160] [160] Wu M, Ha ST, Shendre S, Durmusoglu EG, Koh W-K, Abujetas DR, Sánchez-Gil JA, Paniagua-Domínguez R, Demir HV, Kuznetsov AI. Room-temperature lasing in colloidal nanoplatelets via mie-resonant bound states in the continuum. Nano Lett. 2020;20(8):6005–6011.10.1021/acs.nanolett.0c01975

[161] [161] Zhen B, Chua S-L, Lee J, Rodriguez AW, Liang X, Johnson SG, Joannopoulos JD, Soljačić M, Shapira O. Enabling enhanced emission and low-threshold lasing of organic molecules using special Fano resonances of macroscopic photonic crystals. Proc Natl Acad Sci. 2013;110(34):13711–13716.

[162] [162] Sun T, Kan S, Marriott G, Chang-Hasnain C. High-contrast grating resonators for label-free detection of disease biomarkers. Sci Rep. 2016;6(1):Article 27482.

[163] [163] Sarieddeen H, Saeed N, Al-Naffouri TY, Alouini MS. Next generation terahertz communications: a rendezvous of sensing, imaging, and localization. IEEE Commun Mag. 2020;58(5):69–75.

[164] [164] Zhang D, Kroh T, Ritzkowsky F, Rohwer T, Fakhari M, Cankaya H, Calendron A-L, Matlis NH, Kärtner FX. THz-enhanced DC ultrafast electron diffractometer. Ultrafast Sci. 2021;2021:Article 9848526.

[165] [165] Tonouchi M. Cutting-edge terahertz technology. Nat Photonics. 2007;1(2):97–105.

[166] [166] Nagatsuma T, Ducournau G, Renaud CC. Advances in terahertz communications accelerated by photonics. Nat Photonics. 2016;10(6):371–379.

[167] [167] Taday PF. Applications of terahertz spectroscopy to pharmaceutical sciences. Philos Trans R Soc London, Ser A. 2004;362(1815):351–363.

[168] [168] Lewis RA. A review of terahertz sources. J Phys D Appl Phys. 2014;47(37):Article 374001.

[169] [169] Salamin Y, Benea-Chelmus I-C, Fedoryshyn Y, Heni W, Elder DL, Dalton LR, Faist J, Leuthold J. Compact and ultra-efficient broadband plasmonic terahertz field detector. Nat Commun. 2019;10(1):Article 5550.

[170] [170] E Y, Zhang L, Tcypkin A, Kozlov S, Zhang C, Zhang X-C. Broadband THz sources from gases to liquids. Ultrafast Sci. 2021;2021:Article 9891762.

[171] [171] Kühner L, Sortino L, Berté R, Wang J, Ren H, Maier SA, Kivshar Y, Tittl A. Radial bound states in the continuum for polarization-invariant nanophotonics. Nat Commun. 2022;13(1):Article 4992.

[172] [172] Srivastava YK, Ako RT, Gupta M, Bhaskaran M, Sriram S, Singh R. Terahertz sensing of 7 nm dielectric film with bound states in the continuum metasurfaces. Appl Phys Lett. 2019;115(15):Article 151105.

[173] [173] Cong L, Han J, Zhang W, Singh R. Temporal loss boundary engineered photonic cavity. Nat Commun. 2021;12(1):Article 6940.

[174] [174] Cong L, Singh R. Spatiotemporal dielectric metasurfaces for unidirectional propagation and reconfigurable steering of terahertz beams. Adv Mater. 2020;32(28):Article 2001418.

[175] [175] Cong L, Cao W, Zhang X, Tian Z, Gu J, Singh R, Han J, Zhang W. A perfect metamaterial polarization rotator. Appl Phys Lett. 2013;103(17):Article 171107.

[176] [176] Cong L, Xu N, Gu J, Singh R, Han J, Zhang W. Highly flexible broadband terahertz metamaterial quarter-wave plate. Laser Photonics Rev. 2014;84):626–632.

[177] [177] Cong L, Xu N, Han J, Zhang W, Singh R. A tunable dispersion-free terahertz metadevice with pancharatnam–berry-phase-enabled modulation and polarization control. Adv Mater. 2015;27(42):6630–6636.10.1002/adma.201502716

[178] [178] Cong L, Srivastava YK, Solanki A, Sum TC, Singh R. Perovskite as a platform for active flexible metaphotonic devices. ACS Photonics. 2017;4(7):1595–1601.10.1021/acsphotonics.7b00191

[179] [179] Han S, Cong L, Srivastava YK, Qiang B, Rybin MV, Kumar A, Jain R, Lim WX, Achanta VG, Prabhu SS, et al. All-dielectric active terahertz photonics driven by bound states in the continuum. Adv Mater. 2019;31(37):Article 1901921.

[180] [180] Fan K, Shadrivov IV, Padilla WJ. Dynamic bound states in the continuum. Optica. 2019;6(2):169–173.

[181] [181] Bi L, Hu J, Jiang P, Kim DH, Dionne GF, Kimerling LC, Ross CA. On-chip optical isolation in monolithically integrated non-reciprocal optical resonators. Nat Photonics. 2011;5(12):758–762.

[182] [182] Ignatyeva DO, Belotelov VI. Bound states in the continuum enable modulation of light intensity in the Faraday configuration. Opt Lett. 2020;45(23):6422–6425.

[183] [183] Dong Z, Mahfoud Z, Paniagua-Domínguez R, Wang H, Fernández-Domínguez AI, Gorelik S, Ha ST, Tjiptoharsono F, Kuznetsov AI, Bosman M, et al. Nanoscale mapping of optically inaccessible bound-states-in-the-continuum. Light Sci Appl. 2022;11(1):Article 20.