1. M G Bruce , H L Chen, and X L Steven, Opt.Lett.Vol. 25(2000) , p.1231.
2. Mao W, Zhang S L, Zhang L Q, Acta Phys. Sin. Vol. 55(2006) , p.4704 (in Chinese).
3. H Q Li, A C Geng, Y Bo, Chin. Phys. Vol. 14(2005) , p. (2026).
4. S H Waleed, C David and C S Johndale , App1ied Optics, Vol. 31(1992) , p.4973.
5. Q X Gong, S L Wang, M J Huang, Chin. Phys. Vol. 14(2005) , p. (2004).