[1] Fülöp J A, Tzortzakis S, Kampfrath T. Laser-driven strong-field terahertz sources[J]. Advanced Optical Materials, 8, 1900681(2020).

[2] Genevet P, Capasso F, Aieta F et al. Recent advances in planar optics: from plasmonic to dielectric metasurfaces[J]. Optica, 4, 139-152(2017).

[3] Blanchard F, Razzari L, Bandulet H C et al. Generation of 1.5 µJ single-cycle terahertz pulses by optical rectification from a large aperture ZnTe crystal[J]. Optics Express, 15, 13212-13220(2007).

[4] Hauri C P, Ruchert C, Vicario C et al. Strong-field single-cycle THz pulses generated in an organic crystal[J]. Applied Physics Letters, 99, 161116(2011).

[5] Ruchert C, Vicario C, Hauri C P. Scaling submillimeter single-cycle transients toward megavolts per centimeter field strength via optical rectification in the organic crystal OH1[J]. Optics Letters, 37, 899-901(2012).

[6] Ruchert C, Vicario C, Hauri C P. Spatiotemporal focusing dynamics of intense supercontinuum THz pulses[J]. Physical Review Letters, 110, 123902(2013).

[7] Boyd R W. Material slow light and structural slow light: similarities and differences for nonlinear optics[J]. Journal of the Optical Society of America B, 28, A38-A44(2011).

[8] Weis R S, Gaylord T K. Lithium niobate: summary of physical properties and crystal structure[J]. Applied Physics A, 37, 191-203(1985).

[9] Yang K H, Richards P L, Shen Y R. Generation of far-infrared radiation by picosecond light pulses in LiNbO3[J]. Applied Physics Letters, 19, 320-323(1971).

[10] Hebling J, Almasi G, Kozma I Z et al. Velocity matching by pulse front tilting for large area THz-pulse generation[J]. Optics Express, 10, 1161-1166(2002).

[11] Wu X J, Kong D Y, Hao S B et al. Generation of 13.9-mJ terahertz radiation from lithium niobate materials[J]. Advanced Materials, 35, e2208947(2023).

[12] Chuang S L, Schmitt-Rink S, Greene B I et al. Optical rectification at semiconductor surfaces[J]. Physical Review Letters, 68, 102-105(1992).

[13] Auston D H, Cheung K P, Valdmanis J A et al. Cherenkov radiation from femtosecond optical pulses in electro-optic media[J]. Physical Review Letters, 53, 1555-1558(1984).

[14] Hattori T, Takeuchi K. Simulation study on cascaded terahertz pulse generation in electro-optic crystals[J]. Optics Express, 15, 8076-8093(2007).

[15] Jewariya M, Nagai M, Tanaka K. Enhancement of terahertz wave generation by cascaded χ(2) processes in LiNbO3[J]. Journal of the Optical Society of America B, 26, A101-A106(2009).

[16] Fülöp J A, Pálfalvi L, Almási G et al. Design of high-energy terahertz sources based on optical rectification[J]. Optics Express, 18, 12311-12327(2010).

[17] Huang S W, Granados E, Huang W R et al. High conversion efficiency, high energy terahertz pulses by optical rectification in cryogenically cooled lithium niobate[J]. Optics Letters, 38, 796-798(2013).

[18] Boes A, Chang L, Langrock C et al. Lithium niobate photonics: unlocking the electromagnetic spectrum[J]. Science, 379, eabj4396(2023).

[19] Stepanov A G, Hebling J, Kuhl J. Efficient generation of subpicosecond terahertz radiation by phase-matched optical rectification using ultrashort laser pulses with tilted pulse fronts[J]. Applied Physics Letters, 83, 3000-3002(2003).

[20] Hebling J, Stepanov A G, Almási G et al. Tunable THz pulse generation by optical rectification of ultrashort laser pulses with tilted pulse fronts[J]. Applied Physics B, 78, 593-599(2004).

[21] Stepanov A G, Kuhl J, Kozma I Z et al. Scaling up the energy of THz pulses created by optical rectification[J]. Optics Express, 13, 5762-5768(2005).

[22] Stepanov A G, Bonacina L, Chekalin S V et al. Generation of 30 μJ single-cycle terahertz pulses at 100 Hz repetition rate by optical rectification[J]. Optics Letters, 33, 2497-2499(2008).

[23] Stepanov A G, Henin S, Petit Y et al. Mobile source of high-energy single-cycle terahertz pulses[J]. Applied Physics B, 101, 11-14(2010).

[24] Fülöp J A, Pálfalvi L, Klingebiel S et al. Generation of sub-mJ terahertz pulses by optical rectification[J]. Optics Letters, 37, 557-559(2012).

[25] Fülöp J A, Ollmann Z, Lombosi C et al. Efficient generation of THz pulses with 0.4 mJ energy[J]. Optics Express, 22, 20155-20163(2014).

[26] Wu X J, Calendron A L, Ravi K et al. Optical generation of single-cycle 10 MW peak power 100 GHz waves[J]. Optics Express, 24, 21059-21069(2016).

[27] Zhang B L, Ma Z Z, Ma J L et al. 1.4-mJ high energy terahertz radiation from lithium niobates[J]. Laser & Photonics Reviews, 15, 2000295(2021).

[28] Wu X J, Zhou C, Huang W R et al. Temperature dependent refractive index and absorption coefficient of congruent lithium niobate crystals in the terahertz range[J]. Optics Express, 23, 29729-29737(2015).

[29] Abrahams S C, Hamilton W C, Reddy J M. Ferroelectric lithium niobate. 4. Single crystal neutron diffraction study at 24 ℃[J]. Journal of Physics and Chemistry of Solids, 27, 1013-1018(1966).

[30] Gopalan V, Dierolf V, Scrymgeour D A. Defect-domain wall interactions in trigonal ferroelectrics[J]. Annual Review of Materials Research, 37, 449-489(2007).

[31] Lerner P, Legras C, Dumas J P. Stoechiométrie des monocristaux de métaniobate de lithium[J]. Journal of Crystal Growth, 3/4, 231-235(1968).

[32] Kong Y F, Xu J J, Chen X J et al. Ilmenite-like stacking defect in nonstoichiometric lithium niobate crystals investigated by Raman scattering spectra[J]. Journal of Applied Physics, 87, 4410-4414(2000).

[33] Iyi N, Kitamura K, Izumi F et al. Comparative study of defect structures in lithium niobate with different compositions[J]. Journal of Solid State Chemistry, 101, 340-352(1992).

[34] Volk T, Wöhlecke M, Rubinina N. Optical damage resistance in lithium niobate[M]. Günter P, Huignard J P. Photorefractive materials and their applications 2. Springer series in optical sciences, 114, 165-203(2007).

[35] Carrascosa M, Villarroel J, Carnicero J et al. Understanding light intensity thresholds for catastrophic optical damage in LiNbO3[J]. Optics Express, 16, 115-120(2008).

[36] Bryan D A, Gerson R, Tomaschke H E. Increased optical damage resistance in lithium niobate[J]. Applied Physics Letters, 44, 847-849(1984).

[37] Sweeney K L, Halliburton L E, Bryan D A et al. Point defects in Mg-doped lithium niobate[J]. Journal of Applied Physics, 57, 1036-1044(1985).

[38] Arizmendi L, Powell R C. Anisotropic self-diffraction in Mg-doped LiNbO3[J]. Journal of Applied Physics, 61, 2128-2131(1987).

[39] Wang H, Wen J K, Li J A et al. Photoinduced hole carriers and enhanced resistance to photorefraction in Mg-doped LiNbO3 crystals[J]. Applied Physics Letters, 57, 344-345(1990).

[40] Zhang G Q, Tomita Y. Broadband absorption changes and sensitization of near-infrared photorefractivity induced by ultraviolet light in LiNbO3:Mg[J]. Journal of Applied Physics, 91, 4177-4180(2002).

[41] Pálfalvi L, Hebling J, Almási G et al. Nonlinear refraction and absorption of Mg doped stoichiometric and congruent LiNbO3[J]. Journal of Applied Physics, 95, 902-908(2004).

[42] Chen S L, Liu H D, Kong Y F et al. The resistance against optical damage of near-stoichiometric LiNbO3∶Mg crystals prepared by vapor transport equilibration[J]. Optical Materials, 29, 885-888(2007).

[43] Zhao X A. Microscopic properties of Mg in Li and Nb sites of LiNbO3 by first-principle hybrid functional: formation and related optical properties[J]. The Journal of Physical Chemistry C, 121, 8968-8975(2017).

[44] Sun D H, Song W, Li L L et al. Origin of ferroelectric modification: the thermal behavior of dopant ions[J]. Crystal Growth & Design, 18, 4860-4863(2018).

[45] Sun D H, Kang X L, Yu Q A et al. Antisite defect elimination through Mg doping in stoichiometric lithium tantalate powder synthesized viaa wet-chemical spray-drying method[J]. Journal of Applied Crystallography, 48, 377-385(2015).

[46] Kimura H, Uda S. Conversion of non-stoichiometry of LiNbO3 to constitutional stoichiometry by impurity doping[J]. Journal of Crystal Growth, 311, 4094-4101(2009).

[47] Svaasand L O, Eriksrud M, Grande A P et al. Crystal growth and properties of LiNb3O8[J]. Journal of Crystal Growth, 18, 179-184(1973).

[48] Abdi F, Aillerie M, Bourson P et al. Electro-optic properties in pure LiNbO3 crystals from the congruent to the stoichiometric composition[J]. Journal of Applied Physics, 84, 2251-2254(1998).

[49] Kong Y, Li B, Chen Y et al. The highly optical damage resistance of lithium niobate crystals doping with Mg near its second threshold[C], 53(2003).

[50] Gopalan V, Mitchell T E, Furukawa Y et al. The role of nonstoichiometry in 180° domain switching of LiNbO3 crystals[J]. Applied Physics Letters, 72, 1981-1983(1998).

[51] Furukawa Y, Kitamura K, Takekawa S et al. The correlation of MgO-doped near-stoichiometric LiNbO3 composition to the defect structure[J]. Journal of Crystal Growth, 211, 230-236(2000).

[52] Yan T, Leng Y H, Yu Y G et al. Growth of MgO doped near stoichiometric LiNbO3 single crystals by a hanging crucible Czochralski method using a ship lockage type powder feeding system assisted by numerical simulation[J]. CrystEngComm, 16, 6593-6602(2014).

[53] Buzády A, Gálos R, Makkai G et al. Temperature-dependent terahertz time-domain spectroscopy study of Mg-doped stoichiometric lithium niobate[J]. Optical Materials Express, 10, 998-1006(2020).

[54] Jang D, Sung J H, Lee S K et al. Generation of 0.7 mJ multicycle 15 THz radiation by phase-matched optical rectification in lithium niobate[J]. Optics Letters, 45, 3617-3620(2020).

[55] Wang F L, Sun D H, Liu Q L et al. Growth of large size near-stoichiometric lithium niobate single crystals with low coercive field for manufacturing high quality periodically poled lithium niobate[J]. Optical Materials, 125, 112058(2022).

[56] Bodrov S B, Murzanev A A, Sergeev Y A et al. Terahertz generation by tilted-front laser pulses in weakly and strongly nonlinear regimes[J]. Applied Physics Letters, 103, 251103(2013).

[57] Huang W R, Huang S W, Granados E et al. Highly efficient terahertz pulse generation by optical rectification in stoichiometric and cryo-cooled congruent lithium niobate[J]. Journal of Modern Optics, 62, 1486-1493(2015).

[58] Ravi K, Huang W R, Carbajo S et al. Limitations to THz generation by optical rectification using tilted pulse fronts[J]. Optics Express, 22, 20239-20251(2014).

[59] Kim Y S, Smith R T. Thermal expansion of lithium tantalate and lithium niobate single crystals[J]. Journal of Applied Physics, 40, 4637-4641(1969).

[60] Xu G B, Mu X D, Ding Y J et al. Efficient generation of backward terahertz pulses from multiperiod periodically poled lithium niobate[J]. Optics Letters, 34, 995-997(2009).

[61] Avetisyan Y, Zhang C H, Tonouchi M. Analysis of linewidth tunable terahertz wave generation in periodically poled lithium niobate[J]. Journal of Infrared, Millimeter, and Terahertz Waves, 33, 989-998(2012).

[62] Ravi K, Schimpf D N, Kärtner F X. Pulse sequences for efficient multi-cycle terahertz generation in periodically poled lithium niobate[J]. Optics Express, 24, 25582-25607(2016).

[63] Pickwell E, Wallace V P. Biomedical applications of terahertz technology[J]. Journal of Physics D: Applied Physics, 39, R301-R310(2006).

[64] Lee M, Katz H E, Erben C et al. Broadband modulation of light by using an electro-optic polymer[J]. Science, 298, 1401-1403(2002).

[65] Hoffmann M C, Fülöp J A. Intense ultrashort terahertz pulses: generation and applications[J]. Journal of Physics D: Applied Physics, 44, 083001(2011).

[66] Huang Y D, Meng C, Zhao J et al. High-harmonic and terahertz wave spectroscopy (HATS) for aligned molecules[J]. Journal of Physics B: Atomic, Molecular and Optical Physics, 49, 235601(2016).

[67] Tang H, Zhao L R, Zhu P F et al. Stable and scalable multistage terahertz-driven particle accelerator[J]. Physical Review Letters, 127, 074801(2021).

[68] Xu H X, Yan L X, Du Y C et al. Cascaded high-gradient terahertz-driven acceleration of relativistic electron beams[J]. Nature Photonics, 15, 426-430(2021).

[69] Park H, Camper A, Kafka K et al. High-order harmonic generations in intense MIR fields by cascade three-wave mixing in a fractal-poled LiNbO3 photonic crystal[J]. Optics Letters, 42, 4020-4023(2017).

[70] Carletti L, Li C, Sautter J et al. Second harmonic generation in monolithic lithium niobate metasurfaces[J]. Optics Express, 27, 33391-33398(2019).

[71] Ma J J, Chen J X, Ren M X et al. Second-harmonic generation and its nonlinear depolarization from lithium niobate thin films[J]. Optics Letters, 45, 145-148(2019).

[72] Shcherbakov M R, Werner K, Fan Z Y et al. Photon acceleration and tunable broadband harmonics generation in nonlinear time-dependent metasurfaces[J]. Nature Communications, 10, 1345(2019).

[73] Chen Z, Zhou X B, Werley C A et al. Generation of high power tunable multicycle teraherz pulses[J]. Applied Physics Letters, 99, 071102(2011).

[74] Tian Q L, Xu H X, Wang Y et al. Efficient generation of a high-field terahertz pulse train in bulk lithium niobate crystals by optical rectification[J]. Optics Express, 29, 9624-9634(2021).

[75] Zhang B L, Wu X J, Wang X A et al. Efficient multicycle terahertz pulse generation based on the tilted pulse-front technique[J]. Optics Letters, 47, 2678-2681(2022).

[76] Armstrong J A, Bloembergen N, Ducuing J et al. Interactions between light waves in a nonlinear dielectric[J]. Physical Review, 127, 1918-1939(1962).

[77] Liang X, Yu Y W, Liu R J et al. Flexoelectricity in periodically poled lithium niobate by PFM[J]. Journal of Physics D: Applied Physics, 55, 335303(2022).

[78] Rustagi K, Mehendale S, Meenakshi S. Optical frequency conversion in quasi-phase-matched stacks of nonlinear crystals[J]. IEEE Journal of Quantum Electronics, 18, 1029-1041(1982).

[79] Eyres L A, Tourreau P J, Pinguet T J et al. All-epitaxial fabrication of thick, orientation-patterned GaAs films for nonlinear optical frequency conversion[J]. Applied Physics Letters, 79, 904-906(2001).

[80] Yamada M, Nada N, Saitoh M et al. First-order quasi-phase matched LiNbO3 waveguide periodically poled by applying an external field for efficient blue second-harmonic generation[J]. Applied Physics Letters, 62, 435-436(1993).

[81] Wang T X, Chen P C, Xu C et al. Periodically poled LiNbO3 crystals from 1D and 2D to 3D[J]. Science China Technological Sciences, 63, 1110-1126(2020).

[82] Hadfield R H. Single-photon detectors for optical quantum information applications[J]. Nature Photonics, 3, 696-705(2009).

[83] Takesue H, Nam S W, Zhang Q et al. Quantum key distribution over a 40-dB channel loss using superconducting single-photon detectors[J]. Nature Photonics, 1, 343-348(2007).

[84] Boes A, Corcoran B, Chang L et al. Status and potential of lithium niobate on insulator (LNOI) for photonic integrated circuits[J]. Laser & Photonics Reviews, 12, 1700256(2018).

[85] Desiatov B, Lončar M. Silicon photodetector for integrated lithium niobate photonics[J]. Applied Physics Letters, 115, 121108(2019).

[86] Kong Y F, Bo F, Wang W W et al. Recent progress in lithium niobate: optical damage, defect simulation, and on-chip devices[J]. Advanced Materials, 32, 1806452(2020).

[87] Ahr F, Jolly S W, Matlis N H et al. Narrowband terahertz generation with chirped-and-delayed laser pulses in periodically poled lithium niobate[J]. Optics Letters, 42, 2118-2121(2017).

[88] Carbajo S, Schulte J, Wu X J et al. Efficient narrowband terahertz generation in cryogenically cooled periodically poled lithium niobate[J]. Optics Letters, 40, 5762-5765(2015).

[89] Jolly S W, Matlis N H, Ahr F et al. Spectral phase control of interfering chirped pulses for high-energy narrowband terahertz generation[J]. Nature Communications, 10, 2591(2019).

[90] Lemery F, Vinatier T, Mayet F et al. Highly scalable multicycle THz production with a homemade periodically poled macrocrystal[J]. Communications Physics, 3, 150(2020).

[91] Hamazaki J, Ogawa Y, Kishimoto T et al. Conversion efficiency improvement of terahertz wave generation laterally emitted by a ridge-type periodically poled lithium niobate[J]. Optics Express, 30, 11472-11478(2022).

[92] Pastor-Graells J, Cortés L R, Fernández-Ruiz M R et al. SNR enhancement in high-resolution phase-sensitive OTDR systems using chirped pulse amplification concepts[J]. Optics Letters, 42, 1728-1731(2017).

[93] Shen Y C, Upadhya P C, Linfield E H et al. Ultrabroadband terahertz radiation from low-temperature-grown GaAs photoconductive emitters[J]. Applied Physics Letters, 83, 3117-3119(2003).

[94] Hafez H A, Kovalev S, Deinert J C et al. Extremely efficient terahertz high-harmonic generation in graphene by hot Dirac fermions[J]. Nature, 561, 507-511(2018).

[95] Tu Y Y, Sun X, Wu H Z et al. Enhanced terahertz generation from the lithium niobate metasurface[J]. Frontiers in Physics, 10, 883703(2022).