[1] [1] A. Mehta,T. Thundat,M. D. Barnes et al.. Size-correlated spectroscopy and imaging of rare-earth-doped nanocrystals[J]. Appl. Opt.,2003,42(12):2132-2139

[2] [2] M. Wang,C. C. Mi,W. X. Wang et al.. Immunolabeling and NIR-excited fluorescent imaging of HeLa cells by using NaYF4:Yb,Er upconversion nanoparticles[J]. ACS Nano,2009,3(6):1580-1586

[3] [3] M. Bruchez,M. Moronne,P.Gin et al.. Semiconductor nanocrystals as fluorescent biological labels[J]. Science,1998,281(5385):2013-2016

[4] [4] J. Yang,C. M. Zhang,C. Peng et al.. Controllable red,green,blue (RGB) and bright white upconversion luminescence of Lu2O3:Yb3+/Er3+/Tm3+ nanocrystals through single laser excitation at 980 nm[J]. Chem. Eur. J.,2009,15:4649-4655

[5] [5] Yu Chunlei,He Dongbing,Wang Guonian et al.. The effects of Yb3+/Tm3+/Ho3+ doping concentration on 2 μm wavelength luminscence ingermanium glasses[J]. Acta Optica Sinica,2009,29(11):3143-3147

[6] [6] Lin Qiongfei,Xia Haiping,Wang Jinhao et al.. Spectral properties of Tm3+-doped SiO2-Al2O3-PbF2-AlF3 glasses[J]. Acta Optica Sinica,2008,28(2):305-310

[7] [7] Dong Qinglei,Zhang Liyan,Hu Lili. Crystalization stability and spectral properties of Yb3+-doped alkaline metal modified fluorophosphates glasses[J]. Acta Optica Sinica,2008,28(12):2383-2387

[8] [8] S. Sun,M. Brandt,M. S. Dargusch,Review of laser assisted machining of ceramics[J]. Chinese J. Lasers,2009,36(12):3299-3307

[9] [9] Liao Meisong,Fang Yongzheng,Sun Hongtao et al.. Structure,thermal properties and spectral properties of Tm3+-doped fluorophosphate glasses[J]. Acta Optica Sinica,2006,26(5):713-719

[10] [10] Y. Guyot,R. Moncorgd,L. D. Merkle et al.. Luminescece properties of Y2O3 single crystals doped with Pr3+ or Tm3+ and codoped with Yb3+,Tb3+ or Ho3+ ions[J]. Opt. Mater.,1996,5:127-136

[11] [11] G. Y. Chen,H. C. Liu,Z. G. Zhang et al.. Upconversion emission enhancement in Yb3+/Er3+-codoped Y2O3 nanocrystals by tridoping with Li+ ions[J]. J. Phys. Chem. C,2008,112:12030-12036

[12] [12] G. S. Maciel,R. B. Guimares,P.G. Barreto et al.. The influence of Yb3+ doping on the upconversion luminescence of Pr3+ in aluminum oxide based powders prepared by combustion synthesis[J]. Opt. Mater.,2009,31:1735-1740

[13] [13] L. Q. An,J. Zhang,M. Liu et al.. Up-conversion properties of Yb3+,Ho3+:Lu2O3 sintered ceramic[J]. J. Lumin.,2007,122-123:125-127

[14] [14] Y. P. Li,J. H. Zhang,X. Zhang et al.. Near-infrared to visible upconversion in Er3+ and Yb3+ codoped Lu2O3 nanocrystals:enhanced red color upconversion and three-photon process in green color upconversion[J]. J. Phys. Chem. C,2009,113(11):4413-4418

[15] [15] L. Q. An,J. Zhang,M. Liu et al.. Upconversion luminescence of Tm3+ and Yb3+ codoped lutetium oxide nanopowders[J]. J. Alloys Compd.,2008,451(1):538-541

[16] [16] S. B. Krubanidhi,M. Sayer,Position and pressure effects in rf magnetron reactive sputter deposition of piezoelectric zinc oxide[J]. J. Appl. Phys.,1984,56(11):3308-3318

[17] [17] M. Wermuth,T. Riedener,H. U. Gudel. Spectroscopy and upconversion mechanisms of CsCdBr3:Dy3+[J]. Phys. Rev. B,1998,57(8):4369-4376

[18] [18] F. Vetrone,J. C. Boyer,J. A. Capobianco et al.. Significance of Yb3+ concentration on the upconversion mechanisms in codoped Y2O3:Er3+,Yb3+ nanocrystals[J]. J. Appl. Phys.,2004,96(1):661-667

[19] [19] X. F. Wang,S. G. Xiao,J. W. Ding et al.. (β-Na(Y1.5Na0.5)F6:Tm3+-A blue upconversion phosphor[J]. J. Lumin.,2009,129(3):325-327

[20] [20] X. J. Pei,Y. B. Hou,S. L. Zhao et al.. Frequency upconversion of Tm3+ and Yb3+ codoped YLiF4 synthesized by hydrothermal method[J]. Mater. Chem. Phys.,2005,90(2-3):270-274

[21] [21] V. Fiorenzo,J. C. Boyer,J. A. Capobianco. NIR to visible upconversion in nanocrystalline and bulk Lu2O3:Er3+[J]. J. Phys. Chem. B,2002,106(22):5622-5628

[22] [22] An Liqiong,Zhang Jian,Liu Min et al.. Spectroscopic study of Lu2O3:Yb3+,Ho3+ nanopowders[J]. J. Inorganic Materials,2008,23(2):383-386