Defect Structure of Lithium Niobate Crystals

Abstract

Abstract: Lithium niobate is an artificial crystal which integrates electro-optic, acousto-optic, piezoelectric and nonlinear properties, and has been known as “optical silicon” or “photonic silicon”. In recent years, with the rapid development of integrated photonics based on thin film lithium niobate, lithium niobate crystals have received more and more attention. However, lithium niobate is a typical non-stoichiometric crystal, it contains a large number of intrinsic defects, which seriously affects its characteristics. The lithium niobate lattice has good solid-solution to many impurity ions, moreover, its properties vary significantly with the types and concentrations of dopants. As with defect engineering of semiconductors such as silicon, defects have and will continue to have an important effect on crystal performance and integrated photonics based on thin film lithium niobate. This paper briefly reviews the defect structure of lithium niobate crystals, especially the recent progress on thin film lithium niobate crystals, including the intrinsic defect structure, extrinsic defect structure, characterization of defect structure, theoretical calculation of defect structure, and structure-activity relationship between defect structure and crystal properties. We hope it helpful to the current research of lithium niobate integrated photonics.

Key words: lithium niobate, defect structure, thin film lithium niobate, integrated photonics, structure-activity relationship

CLC Number:

O734
O78

LIU Hongde, WANG Weiwei, ZHANG Zhongzheng, ZHENG Dahuai, LIU Shiguo, KONG Yongfa, XU Jingjun. Defect Structure of Lithium Niobate Crystals[J]. JOURNAL OF SYNTHETIC CRYSTALS, 2024, 53(3): 355-371.

References

[1] 汪卫华. 非晶态物质的本质和特性[J]. 物理学进展, 2013, 33(5): 177-351.
WANG W H. The nature and properties of amorphous matter[J]. Progress in Physics, 2013, 33(5): 177-351 (in Chinese).
[2] OLAKANMI E O, COCHRANE R F, DALGARNO K W. A review on selective laser sintering/melting (SLS/SLM) of aluminium alloy powders: processing, microstructure, and properties[J]. Progress in Materials Science, 2015, 74: 401-477.
[3] DAWLEY N M, MARKSZ E J, HAGERSTROM A M, et al. Targeted chemical pressure yields tuneable millimetre-wave dielectric[J]. Nature Materials, 2020, 19: 176-181.
[4] SCHAEDEL L, TRICLIN S, CHRÉTIEN D, et al. Lattice defects induce microtubule self-renewal[J]. Nature Physics, 2019, 15: 830-838.
[5] SAKAI T K, BELYAKOV A, KAIBYSHEV R, et al. Dynamic and post-dynamic recrystallization under hot, cold and severe plastic deformation conditions[J]. Progress in Materials Science, 2014, 60: 130-207.
[6] CUI Y, DUAN X F, HU J T, et al. Doping and electrical transport in silicon nanowires[J]. The Journal of Physical Chemistry B, 2000, 104(22): 5213-5216.
[7] CHEN D, KIM M, STEFANI B V, et al. Evidence of an identical firing-activated carrier-induced defect in monocrystalline and multicrystalline silicon[J]. Solar Energy Materials and Solar Cells, 2017, 172: 293-300.
[8] SAIDAMINOV M I, KIM J, JAIN A, et al. Suppression of atomic vacancies via incorporation of isovalent small ions to increase the stability of halide perovskite solar cells in ambient air[J]. Nature Energy, 2018, 3: 648-654.
[9] LIU Z, QIU W D, PENG X M, et al. Perovskite light-emitting diodes with EQE exceeding 28% through a synergetic dual-additive strategy for defect passivation and nanostructure regulation[J]. Advanced Materials, 2021, 33(43): e2103268.
[10] 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, 2020, 32(3): e1806452.
[11] 郑大怀, 吴婧, 商继芳, 等. 电光调Q晶体研究进展[J]. 中国科学: 技术科学, 2017, 47(11): 1139-1148.
ZHENG D H, WU J, SHANG J F, et al. Progress on electro-optic crystals for Q-switches[J]. Scientia Sinica (Technologica), 2017, 47(11): 1139-1148 (in Chinese).
[12] 高博锋, 任梦昕, 郑大怀, 等. 铌酸锂的耄耋之路:历史与若干进展[J]. 人工晶体学报, 2021, 50(7): 1183-1199.
GAO B F, REN M X, ZHENG D H, et al. Long-lived lithium niobate: history and progress[J]. Journal of Synthetic Crystals, 2021, 50(7): 1183-1199 (in Chinese).
[13] VOLK T, WÖHLECKE M. Lithium niobate: defects, photorefraction and ferroelectric switching[M]. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009.
[14] GUARINO A, POBERAJ G, REZZONICO D, et al. Electro-optically tunable microring resonators in lithium niobate[J]. Nature Photonics, 2007, 1: 407-410.
[15] KÖSTERS M, STURMAN B, WERHEIT P, et al. Optical cleaning of congruent lithium niobate crystals[J]. Nature Photonics, 2009, 3: 510-513.
[16] LEVY M, OSGOOD R M, LIU R, et al. Fabrication of single-crystal lithium niobate films by crystal ion slicing[J]. Applied Physics Letters, 1998, 73(16): 2293.
[17] RABIEI P, GUNTER P. Optical and electro-optical properties of submicrometer lithium niobate slab waveguides prepared by crystal ion slicing and wafer bonding[J]. Applied Physics Letters, 2004, 85(20): 4603.
[18] ZHANG M, WANG C, CHENG R, et al. Monolithic ultra-high-Q lithium niobate microring resonator[J]. Optica, 2017, 4(12): 1536.
[19] WANG C, ZHANG M, CHEN X, et al. Integrated lithium niobate electro-optic modulators operating at CMOS-compatible voltages[J]. Nature, 2018, 562: 101-104.
[20] WU R B, WANG M, XU J, et al. Long low-loss-litium niobate on insulator waveguides with sub-nanometer surface roughness[J]. Nanomaterials, 2018, 8(11): 910.
[21] DESIATOV B, SHAMS-ANSARI A, ZHANG M, et al. Ultra-low-loss integrated visible photonics using thin-film lithium niobate[J]. Optica, 2019, 6(3): 380.
[22] ZHU D, SHAO L B, YU M J, et al. Integrated photonics on thin-film lithium niobate[EB/OL]. 2021: arXiv: 2102.11956. http://arxiv.org/abs/2102.11956
[23] BYER R L, YOUNG J F, FEIGELSON R S. Growth of high-quality LiNbO₃ crystals from the congruent melt[J]. Journal of Applied Physics, 1970, 41(6): 2320-2325.
[24] O'BRYAN H M, GALLAGHER P K, BRANDLE C D. Congruent composition and Li-rich phase boundary of LiNbO₃[J]. Journal of the American Ceramic Society, 1985, 68(9): 493-496.
[25] GRABMAIER B C, WERSING W, KOESTLER W. Properties of undoped and MgO-doped LiNbO₃; correlation to the defect structure[J]. Journal of Crystal Growth, 1991, 110(3): 339-347.
[26] 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, 1998, 84(4): 2251-2254.
[27] KONDO Y, FUKUDA T, YAMASHITA Y, et al. An increase of more than 30% in the electrooptic coefficients of Fe-doped and Ce-doped stoichiometric LiNbO₃ crystals[J]. Japanese Journal of Applied Physics, 2000, 39(3S): 1477.
[28] NAKAMURA M, HIGUCHI S, TAKEKAWA S, et al. Optical damage resistance and refractive indices in near-stoichiometric MgO-doped LiNbO₃[J]. Japanese Journal of Applied Physics, 2002, 41(2): 49-51.
[29] KONG Y F, LIU S G, ZHAO Y J, et al. Highly optical damage resistant crystal: zirconium-oxide-doped lithium niobate[J]. Applied Physics Letters, 2007, 91(8): 081908.
[30] PEITHMANN K, WIEBROCK A, BUSE K. Photorefractive properties of highly-doped lithium niobate crystals in the visible and near-infrared[J]. Applied Physics B, 1999, 68(5): 777-784.
[31] TIAN T, KONG Y F, LIU S G, et al. Photorefraction of molybdenum-doped lithium niobate crystals[J]. Optics Letters, 2012, 37(13): 2679-2681.
[32] DE MICHELI M, BOTINEAU J, NEVEU S, et al. Independent control of index and profiles in proton-exchanged lithium niobate guides[J]. Optics Letters, 1983, 8(2): 114-115.
[33] ZHANG D L, ZHANG Q, QIU C X, et al. Diffusion control of an ion by another in LiNbO₃ and LiTaO₃ crystals[J]. Scientific Reports, 2015, 5: 10018.
[34] LALLIER E. Rare-earth-doped glass and LiNbO₃ waveguide lasers and optical amplifiers[J]. Applied Optics, 1992, 31(25): 5276-5282.
[35] 孔勇发, 许京军, 张光寅, 等. 多功能光电材料: 铌酸锂晶体[M]. 北京: 科学出版社, 2005.
KONG Y F, XU J J, ZHANG G Y, et al. Multifunctional optoelectronic material: lithium niobate crystal[M]. Beijing: Science Press, 2005 (in Chinese).
[36] FAY H, ALFORD W J, DESS H M. Dependence of second-harmonic phase-matching temperature in LiNbO₃ crystals on melt composition[J]. Applied Physics Letters, 1968, 12(3): 89-92.
[37] LERNER P, LEGRAS C, DUMAS J P. Stoechiométrie des monocristaux de métaniobate de lithium[J]. Journal of Crystal Growth, 1968, 3/4: 231-235.
[38] PETERSON G E, CARNEVALE A. 93 Nb NMR linewidths in nonstoichiometric lithium niobate[J]. The Journal of Chemical Physics, 1972, 56(10): 4848-4851.
[39] ABRAHAMS S C, MARSH P. Defect structure dependence on composition in lithium niobate[J]. Acta Crystallographica Section B Structural Science, 1986, 42(1): 61-68.
[40] SAFARYAN F P, FEIGELSON R S, PETROSYAN A M. An approach to the defect structure analysis of lithium niobate single crystals[J]. Journal of Applied Physics, 1999, 85(12): 8079-8082.
[41] TAHIRI M, MASAIF N, JENNANE A. Defect structure analysis of lithium niobate single crystals and lithium tantalate ceramics with the next-nearest-neighbor interactions[J]. Indian Journal of Physics, 2012, 86(7): 595-600.
[42] CHEN K F, LI Y L, PENG C, et al. Microstructure and defect characteristics of lithium niobate with different Li concentrations[J]. Inorganic Chemistry Frontiers, 2021, 8(17): 4006-4013.
[43] SMYTH D M. Defects and transport in LiNbO₃[J]. Ferroelectrics, 1983, 50(1): 93-102.
[44] SCHMIDT F, KOZUB A L, BIKTAGIROV T, et al. Free and defect-bound (bi)polarons in LiNbO₃: atomic structure and spectroscopic signatures fromab initiocalculations[J]. Physical Review Research, 2020, 2(4): 043002.
[45] SCHIRMER O F, VON DER LINDE D. Two-photon- and X-ray-induced Nb⁴⁺ and O^- small polarons in LiNbO₃[J]. Applied Physics Letters, 1978, 33(1): 35-38.
[46] BRÜNING H, DIECKMANN V, SCHOKE B, et al. Small-polaron based holograms in LiNbO₃ in the visible spectrum[J]. Optics Express, 2012, 20(12): 13326.
[47] SCHOKE B, IMLAU M, BRUNING H, et al. Transient light-induced absorption in periodically poled lithium niobate: small polaron hopping in the presence of a spatially modulated defect concentration[J]. Physical Review B, 2010, 81(13): 132301.
[48] REBOUTA L, DA SILVA M F, SOARES J C, et al. Lattice site of iron in LiNbO₃ (Fe³⁺) by the PIXE/channelling technique[J]. Europhysics Letters (EPL), 1991, 14(6): 557-561.
[49] KONG Y F, LIU S G, XU J J. Recent advances in the photorefraction of doped lithium niobate crystals[J]. Materials, 2012, 5(10): 1954-1971.
[50] WANG S L, SHAN Y D, WANG W W, et al. Lone-pair electron effect induced a rapid photorefractive response in site-controlled LiNbO₃∶Bi, M (M = Zn, In, Zr) crystals[J]. Applied Physics Letters, 2021, 118(19): 191902.
[51] SMITH R G, FRASER D B, DENTON R T, et al. Correlation of reduction in optically induced refractive-index inhomogeneity with OH content in LiTaO₃ and LiNbO₃[J]. Journal of Applied Physics, 1968, 39(10): 4600-4602.
[52] HERRINGTON J R, DISCHLER B, RÄUBER A, et al. An optical study of the stretching absorption band near 3 microns from OH^- defects in LiNbO₃[J]. Solid State Communications, 1973, 12(5): 351-354.
[53] KOVÁCS L, SZALAY V, CAPELLETTI R. Stoichiometry dependence of the OH^- absorption band in LiNbO₃ crystals[J]. Solid State Communications, 1984, 52(12): 1029-1031.
[54] KOVÁCS L, WOHLECKE M, JOVANOVIĆ A, et al. Infrared absorption study of the OH vibrational band in LiNbO₃ crystals[J]. Journal of Physics and Chemistry of Solids, 1991, 52(6): 797-803.
[55] KONG Y F, ZHANG W L, CHEN X J, et al. Absorption spectra of pure lithium niobate crystals[J]. Journal of Physics: Condensed Matter, 1999, 11(9): 2139-2143.
[56] KONG Y F, XU J J, ZHANG W L, et al. Proton site occupation in congruent lithium niobate crystal determined by nuclear magnetic resonance[J]. Physics Letters A, 1998, 250(1/2/3): 211-213.
[57] WANG W W, ZHENG D H, HU M Y, et al. Effect of defects on spontaneous polarization in pure and doped LiNbO₃: first-principles calculations[J]. Materials, 2018, 12(1): 100.
[58] LENGYEL K, TIMÓN V, HERNÓNDEZ-LAGUNA A, et al. Structure of OH^- defects in LiNbO₃[J]. IOP Conference Series: Materials Science and Engineering, 2010, 15: 012015.
[59] KOVÁCS L, LENGYEL K, SZALAY V. Combination transitions due to stretching and librations of OH^- ions in LiNbO₃[J]. Optics Letters, 2011, 36(18): 3714-3716.
[60] KÖHLER T, ZSCHORNAK M, RÖDER C, et al. Chemical environment and occupation sites of hydrogen in LiMO₃[J]. Journal of Materials Chemistry C, 2023, 11(2): 520-538.
[61] DRAVECZ G, KOVÁCS L. Determination of the crystal composition from the OH^- vibrational spectrum in lithium niobate[J]. Applied Physics B, 2007, 88(2): 305-307.
[62] KOVÁCS L, SZALLER Z, LENGYEL K, et al. Hydroxyl ions in stoichiometric LiNbO₃ crystals doped with optical damage resistant ions[J]. Optical Materials, 2014, 37: 55-58.
[63] VOLK T, WÖHLECKE M, RUBININA N. Optical damage resistance in lithium niobate[M]//Photorefractive Materials and Their Applications 2. New York, NY: Springer New York, 2007: 165-203.
[64] SCHAUFELE R F, WEBER M J. Raman scattering by lithium niobate[J]. Physical Review, 1966, 152(2): 705-708.
[65] YANG X C, LAN G X, LI B, et al. Raman spectra and directional dispersion in LiNbO₃ and LiTaO₃[J]. Physica Status Solidi B Basic Research, 1987, 142(1): 287-300.
[66] MALOVICHKO G I, GRACHEV V G, KOKANYAN E P, et al. Characterization of stoichiometric LiNbO₃ grown from melts containing K₂O[J]. Applied Physics A, 1993, 56(2): 103-108.
[67] SCHLARB U, KLAUER S, WESSELMANN M, et al. Determination of the Li/Nb ratio in lithium niobate by means of birefringence and Raman measurements[J]. Applied Physics A, 1993, 56(4): 311-315.
[68] RIDAH A, BOURSON P, FONTANA M D, et al. The composition dependence of the Raman spectrum and new assignment of the phonons in LiNbO₃[J]. Journal of Physics: Condensed Matter, 1997, 9(44): 9687-9693.
[69] 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, 2000, 87(9): 4410-4414.
[70] BARAN E J, BOTTO I L, MUTO F, et al. Vibrational spectra of the ilmenite modifications of LiNbO₃ and NaNbO₃[J]. Journal of Materials Science Letters, 1986, 5(6): 671-672.
[71] SIDOROV N V, YANICHEV A A, CHUFYREV P G, et al. Raman spectra of photorefractive lithium niobate single crystals[J]. Journal of Applied Spectroscopy, 2010, 77(1): 110-114.
[72] FONTANA M D, BOURSON P. Microstructure and defects probed by Raman spectroscopy in lithium niobate crystals and devices[J]. Applied Physics Reviews, 2015, 2(4): 040602.
[73] SIDOROV N, PALATNIKOV M, KADETOVA A. Raman scattering in non-stoichiometric lithium niobate crystals with a low photorefractive effect[J]. Crystals, 2019, 9(10): 535.
[74] XUE D F, HE X K. Dopant occupancy and structural stability of doped lithium niobate crystals[J]. Physical Review B, 2006, 73(6): 064113.
[75] HE Y L, XUE D F. Bond-energy study of photorefractive properties of doped lithium niobate crystals[J]. The Journal of Physical Chemistry C, 2007, 111(35): 13238-13243.
[76] LI L L, LI Y L, ZHAO X. Hybrid density functional theory insight into the stability and microscopic properties of Bi-doped LiNbO₃: lone electron pair effect[J]. Physical Review B, 2017, 96(11): 115118.
[77] WANG W W, ZHONG Y, ZHENG D H, et al. P-Type conductivity mechanism and defect structure of nitrogen-doped LiNbO₃ from first-principles calculations[J]. Physical Chemistry Chemical Physics, 2020, 22(1): 20-27.
[78] FENG D, MING N B, HONG J F, et al. Enhancement of second-harmonic generation in LiNbO₃ crystals with periodic laminar ferroelectric domains[J]. Applied Physics Letters, 1980, 37(7): 607-609.
[79] ZHANG Z Y, ZHU Y Y, ZHU S N, et al. Domain inversion by Li₂O out-diffusion or proton exchange followed by heat treatment in LiTaO₃ and LiNbO₃[J]. Physica Status Solidi (a), 1996, 153(1): 275-279.
[80] THIELE F, VOM BRUCH F, QUIRING V, et al. Cryogenic electro-optic polarisation conversion in titanium in-diffused lithium niobate waveguides[J]. Optics Express, 2020, 28(20): 28961-28968.
[81] RAMBU A P, TIRON V, ONICIUC E, et al. Spontaneous polarization reversal induced by proton exchange in Z-cut lithium niobate α-phase channel waveguides[J]. Materials, 2021, 14(23): 7127.
[82] KOKHANCHIK L S, EMELIN E V, SIROTKIN V V. Large regular arrays with submicron domains written by low-voltage e-beam on -Z cut of lithium niobate[J]. Optical Materials, 2022, 128: 112405.
[83] KOKHANCHIK L S, EMELIN E V, SIROTKIN V V, et al. Deepening of domains at e-beam writing on the -Z surface of lithium niobate[J]. Journal of Physics D: Applied Physics, 2022, 55(19): 195302.
[84] ALIKIN Y M, TURYGIN A P, ALIKIN D O, et al. Interaction of wedge-like domains created by local polarization reversal on nonpolar cut of lithium niobate[J]. Ferroelectrics, 2023, 604(1): 25-31.
[85] KIPENKO I A, AKHMATKHANOV A R, CHUVAKOVA M A, et al. Domain wall motion and Barkhausen pulses in lithium niobate with tailored regular 2D domain structure[J]. Ferroelectrics, 2023, 604(1): 40-46.
[86] GUO J X, CHEN W W, CHEN H S, et al. Recent progress in optical control of ferroelectric polarization[J]. Advanced Optical Materials, 2021, 9(23): 2002146.
[87] WANG X L, CAO Q, WANG R N, et al. Domain growth driven by a femtosecond laser in lithium niobate crystal[J]. Optics Letters, 2023, 48(3): 566-569.
[88] VALDIVIA C E, SONES C L, MAILIS S, et al. Ultrashort-pulse optically-assisted domain engineering in lithium niobate[J]. Ferroelectrics, 2006, 340(1): 75-82.
[89] WEBJORN J, LAURELL F, ARVIDSSON G. Fabrication of periodically domain-inverted channel waveguides in lithium niobate for second harmonic generation[J]. Journal of Lightwave Technology, 1989, 7(10): 1597-1600.
[90] 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, 1993, 62(5): 435-436.
[91] 张志勇, 朱永元, 祝世宁, 等. 一种制备LiNbO₃周期性畴反转的新方法[J]. 人工晶体学报, 1995, 24(1): 1-4.
ZHANG Z Y, ZHU Y Y, ZHU S N, et al. A new method for preparing periodic domain inversion of LiNbO₃[J]. Journal of Synthetic Crystals, 1995, 24(1): 1-4 (in Chinese).
[92] CHEN Y L, LOU C B, XU J J, et al. Domain switching characteristics of the near stoichiometric LiNbO₃ doped with MgO[J]. Journal of Applied Physics, 2003, 94(5): 3350-3352.
[93] ZENG H, KONG Y F, LIU H D, et al. Light-induced superlow electric field for domain reversal in near-stoichiometric magnesium-doped lithium niobate[J]. Journal of Applied Physics, 2010, 107(6): 063514.
[94] FUJIMURA M, SOHMURA T, SUHARA T. Fabrication of domain-inverted gratings in MgO∶LiNbO₃ by applying voltage under ultraviolet irradiation through photomask at room temperature[J]. Electronics Letters, 2003, 39(9): 719.
[95] WENGLER M C, FASSBENDER B, SOERGEL E, et al. Impact of ultraviolet light on coercive field, poling dynamics and poling quality of various lithium niobate crystals from different sources[J]. Journal of Applied Physics, 2004, 96(5): 2816-2820.
[96] WENGLER M C, HEINEMEYER U, SOERGEL E, et al. Ultraviolet light-assisted domain inversion in magnesium-doped lithium niobate crystals[J]. Journal of Applied Physics, 2005, 98(6): 064104.
[97] WANG W J, KONG Y F, LIU H D, et al. Light-induced domain reversal in doped lithium niobate crystals[J]. Journal of Applied Physics, 2009, 105(4): 043105.
[98] ZHU H S, CHEN X F, CHEN H Y, et al. Formation of domain reversal by direct irradiation with femtosecond laser in lithium niobate[J]. Chinese Optics Letters, 2009, 7(2): 169-172.
[99] XU X Y, WANG T X, CHEN P C, et al. Femtosecond laser writing of lithium niobate ferroelectric nanodomains[J]. Nature, 2022, 609: 496-501.
[100] ASHKIN A, BOYD G D, DZIEDZIC J M, et al. Optically-induced refractive index inhomogeneities in LiNbO₃ and LiTaO₃[J]. Applied Physics Letters, 1966, 9(1): 72-74.
[101] ZHONG G, JIAN J, WU Z. Measurement of optically induced refractive-index change of lithium niobate doped with different concentration of MgO[J]. Proceedings of the 11th International Quantum Electronics Conference, 1980.
[102] VOLK T R, PRYALKIN V I, RUBININA N M. Optical-damage-resistant LiNbO₃∶Zn crystal[J]. Optics Letters, 1990, 15(18): 996-998.
[103] YAMAMOTO J K, KITAMURA K, IYI N, et al. Increased optical damage resistance in Sc₂O₃-doped LiNbO₃[J]. Applied Physics Letters, 1992, 61(18): 2156-2158.
[104] KONG Y F, WEN J K, WANG H F. New doped lithium niobate crystal with high resistance to photorefraction—LiNbO₃∶In[J]. Applied Physics Letters, 1995, 66(3): 280-281.
[105] LI S Q, LIU S G, KONG Y F, et al. The optical damage resistance and absorption spectra of LiNbO₃∶Hf crystals[J]. Journal of Physics Condensed Matter, 2006, 18(13): 3527-3534.
[106] WANG L Z, LIU S G, KONG Y F, et al. Increased optical-damage resistance in tin-doped lithium niobate[J]. Optics Letters, 2010, 35(6): 883-885.
[107] LIU F C, KONG Y F, LI W, et al. High resistance against ultraviolet photorefraction in zirconium-doped lithium niobate crystals[J]. Optics Letters, 2010, 35(1): 10-12.
[108] IYI N, KITAMURA K, YAJIMA Y, et al. Defect structure model of MgO-doped LiNbO₃[J]. Journal of Solid State Chemistry, 1995, 118(1): 148-152.
[109] LIU J J, ZHANG W L, ZHANG G Y. Defect chemistry analysis of the defect structure in Mg-doped LiNbO₃ crystals[J]. Physica Status Solidi (a), 1996, 156(2): 285-291.
[110] AILLERIE M, BOURSON P, MOSTEFA M, et al. Photorefractive damage in congruent LiNbO₃. part II. magnesium doped lithium niobate crystals[J]. Journal of Physics: Conference Series, 2013, 416: 012002.
[111] LI Y L, LI L L, CHENG X F, et al. Microscopic properties of Mg in Li and Nb sites of LiNbO₃ by first-principle hybrid functional: formation and related optical properties[J]. Journal of Physical Chemistry C, 2017, 121(16): 8968-8975.
[112] ZHENG D H, KONG Y F, LIU S G, et al. The simultaneous enhancement of photorefraction and optical damage resistance in MgO and Bi₂O₃ Co-doped LiNbO₃ crystals[J]. Scientific Reports, 2016, 6: 20308.
[113] JIANG H W, LUO R, LIANG H X, et al. Fast response of photorefraction in lithium niobate microresonators[J]. Optics Letters, 2017, 42(17): 3267-3270.
[114] LU J J, SURYA J B, LIU X W, et al. Periodically poled thin-film lithium niobate microring resonators with a second-harmonic generation efficiency of 250, 000%/W[J]. Optica, 2019, 6(12): 1455.
[115] HU H, GUI L, RICKEN R, et al. Towards nonlinear photonic wires in lithium niobate[C]//SPIE OPTO. Proc SPIE 7604, Integrated Optics: Devices, Materials, and Technologies XIV, San Francisco, California, USA. 2010, 7604: 183-194.
[116] WU R B, ZHANG J H, YAO N, et al. Lithium niobate micro-disk resonators of quality factors above 10⁷[J]. Optics Letters, 2018, 43(17): 4116-4119.
[117] ZHANG M, BUSCAINO B, WANG C, et al. Broadband electro-optic frequency comb generation in a lithium niobate microring resonator[J]. Nature, 2019, 568: 373-377.
[118] WANG S H, YANG L K, CHENG R S, et al. Incorporation of erbium ions into thin-film lithium niobate integrated photonics[J]. Applied Physics Letters, 2020, 116(15): 151103.
[119] WANG Z, FANG Z W, LIU Z X, et al. On-chip tunable microdisk laser fabricated on Er³⁺-doped lithium niobate on insulator[J]. Optics Letters, 2021, 46(2): 380-383.
[120] LIU Y A, YAN X S, WU J W, et al. On-chip erbium-doped lithium niobate microcavity laser[J]. Science China Physics, Mechanics & Astronomy, 2020, 64(3): 234262.
[121] LUO Q, HAO Z Z, YANG C, et al. Microdisk lasers on an erbium-doped lithium-niobite chip[J]. Science China Physics, Mechanics & Astronomy, 2020, 64(3): 234263.
[122] XIE Z D, ZHU S N. LiNbO₃ crystals: from bulk to film[J]. Advanced Photonics, 2022, 4(3): 030502.
[123] LUO Q, BO F, KONG Y F, et al. Advances in lithium niobate thin-film lasers and amplifiers: a review[J]. Advanced Photonics, 2023, 5(3): 034002.