[1] Kramer K W, Gudel H U. Infrared-to-visible upconversion in LaCl: 1% Er3 + Energy-level and line-strength calculation.Phys Res(B) ,1997,56(21) :13830 ～ 13840

[2] Tsuda M, Soga K, Inoue H. Upconversion mechanism in Er3+ -doped fluorozirconate glasses under 800 nm excitation.J Appl Phys, 1999,85( 1 ) :29 ～ 37

[3] Takahashi M, Shojiya M, Kanno R. Nonradiative decay processes and mechanisms of frequency upconversion of Er3 + in ZrF4-BaF2-LaF3 glass. J Appl Phys, 1997 ,81 (7) :2940 ～2945

[4] Zalucha D J, Wright J C. Energy transfer upconversion in LaF3 :Pr3+ . J Chem Phys,1973,59(3) :997～1001

[6] Huang X, Cutinha N, Alcazar De V A. Upconversion in erbium doped YAG ion-implanted waveguides. Nucl Instr And Meth in phys Res, 1998, B142:50 ～ 60

[7] Yu X Y, Luo Q, Li L W, et al. Ultrafast phase dynamics of coherent carriers in GaAs. Appl Phys Lett, 1998,73 ( 23 ):3321 ～ 3323

[8] Luo Q, et al. Time-resolved phase spectroscopy from femtosecond free induction decay. Appl Phys B : Lasers Opt,2000,70:53 ～ 56

[9] Alexander A K. Laser Crystals Their Physics and Properties,Springer-Verlag Berlin Heidelberg New York, 1981

[10] Luo Q,Dai D C,Wang G Q,et al. Theory and experiment of coherent wave packet dynamics in rare earth solids:Absorption spectrum versus femtosecond fringe-resolved interferogram. J Chem Phys,2001,114(4) :1870 ～ 1873