Mechanism of the UV band-edge photorefractivity enhancement in near-stoichiometric LiNbO₃

Abstract

The UV photorefractive properties of near-stoichiometric LiNbO₃ single crystal are found to be significantly enhanced compared with the congruent one at 325 nm. The temperature dependence of the band edge of near-stoichiometric LiNbO₃ crystal is investigated. Significant thermal-induced spectral shift in band gap which obeys the Bose-Einstein expression is observed, and the fundamental band gap at zero absolute temperature is found to be much larger than the congruent one. New absorption bands near the UV band edge which are much stronger in the near-stoichiometric LiNbO₃ than those in the congruent LiNbO₃ crystal show up at temperatures lower than ∼400 K. Note that the UV photorefractivity is enhanced in SLN, which has exactly the same tendency as the absorption strength.

References

[1] VolkT, WöhleckeM. Lithium Niobate: Defects, Photorefraction and Ferroelectric Switching, 2008, Berlin, Springer-Verlag

[2] TianB, ChenH, ChogeD, XuY, LiG, LiangW. Optoelectron. Lett., 2017, 13: 206

[3] WuW, MaJ, PanH, WuE, ChenH, DismasK, LiangW. Optoelectron. Lett., 2017, 13: 156

[4] PalS, DasB, WolfgangS. Appl. Phys. B, 2015, 120: 737

[5] ZhengD, KongY, LiuS, ChenM, ChenS, ZhangL, RuppR, XuJ. Sci. Rep., 2016, 6: 20308

[6] ZhengD, KongY, LiuS, YaoJ, ZhangL, ChenS, XuJ. AIP Adv., 2015, 1: 031501

[7] WangJ, ZhuB, HaoZ, BoF, WangX, GaoF, LiY, ZhangG, XuJ. Opt. Express, 2016, 24: 21869

[8] ChenX, LiB, XuJ, ZhuD, PanS, WuZh. J. Appl. Phys., 2001, 90: 1516

[9] XinF, ZhangG, BoF, SunH, KongY, XuJ, VolkT, RubininaN. J. Appl. Phys., 2010, 107: 033113

[10] ViñaL, LogothetidisS, CardonaM. Phys. Rev. B, 1984, 30: 1979

[11] Castillo-TorresJ. Opt. Commun., 2013, 290: 107

[12] CodyG D, TiedjeT, AbelesB, BrooksB, GoldsteinY. Phys. Rev. Lett., 1981, 47: 1480

[13] DowJ D, RedfieldD. Phys. Rev. B, 1972, 5: 594

[14] XinF, ZhaiZ, WangX, KongY, XuJ, ZhangG. Phys. Rev. B, 2012, 86: 165132

[15] HerthP, GranzowT, SchanielD, WoikeTh, ImlauM, KrätzigE. Phys. Rev. Lett., 2005, 95: 067404

[16] MerschjannC, SchokeB, ImlauM. Phys. Rev. B, 2007, 76: 085114

[17] BerbenD, BuseK, WeveringS, HerthP, ImlauM, WoikeTh. J. Appl. Phys., 2000, 87: 1034

This work has been supported by the Doctoral Foundation of Tianjin Normal University (No.135202XB1607).