1. Rossi B., Laser Focus World 33, 143 (1997).
2. Shen Hong-bin, He Hai-jun, Liu Bin-qi, Li Gang, Huang Fuyu and Yan Zong-qun, Journal of Optoelectronics \ Laser 19, 1622 (2008). (in Chinese)
3. Wang Tian-shu, Guo Yu-bin, Wang Ke and Huo Jia-yu, Journal of Optoelectronics \ Laser 19, 31 (2008). (in Chinese)
4. Yan-xing Ma, Lei Si, Xiao-lin Wang, Pu Zhou and Xiao-jun Xu, Optoelectronics Letters 5, 18 (2009).
5. J. Nilsson, J. K. Sahu, Y. Jeong, W. A. Clarkson, R. Selvas, A. B. Grudinin and S. Alamm, Proceedings of SPIE 4974, 50 (2003).