[1] [1] Blasse G, Bril A. Appl. Phys. Lett., 1967, 11: 53.

[2] [2] Blasse G, Bril A. J. Chem. Phys., 1967, 47: 5139.

[3] [3] Mueller-Mach R, Mueller G O, Krames M R, et al., IEEE. J. Sel. Top. Quantum Electron, 2002, 8: 339.

[4] [4] Yang H H, Kim Y A. Journal of Luminescence, 2008, 128: 1570.

[5] [5] Jang H S, Bin W Im, Lee D C, et al. Journal of Luminescence, 2007, 126: 371.

[6] [6] Pan Y, Wu M, Su Q. J. Phys. Chem. Solids, 2004, 65: 845.

[7] [7] Wang W, Tang J, Hus S T. Chem. Phys. Letters, 2008, 457: 103.

[8] [8] Ho Seong Jang, Won Bin Im, Dong Chin Lee, et al. Journal of Luminescence, 2007, 126(2): 371.

[9] [9] Chase A B, Judith A Osmer. Journal of Crystal Growth, 1969, 5: 239.

[10] [10] Henderson B, Imbusch G F. Optical Spectroscopy of Inorganic Solids. Clarendon Press, Oxford, 1989.