[1] Y. Furukawa, K. Kitamura, S. Takekawa, K. Niwa, and H. Hatano, Opt. Lett. 23, 1892 (1998).
[2] Y. Furukawa, K. Kitamura, S. Takekawa, A. Miyamoto, M. Terao, and N. Suda, Appl. Phys. Lett. 77, 2494 (2000).
[3] M. Rahm, U. Bader, G. Anstett, J.-P. Meyn, R. Wallenstein, and A. Borsutzky, Appl. Phys. B 75, 47 (2002).
[4] M. J. Missey, V. Dominic, P. E. Powers, and K. L. Schepler, Opt. Lett. 24, 1227 (1999).
[5] B. Zhang, J. Yao, X. Ding, H. Zhang, P. Wang, D. Xu, G. Yu, and F. Zhang, Chin. Phys. Soc. 13, 364 (2004).
[6] P. Zhao, B. Zhang, E. Li, R. Zhou, D. Xu, Y. Lu, T. Zhang, F. Ji, X. Zhu, P. Wang, and J. Yao, Opt. Express 14, 7224 (2006).
[7] X. Zhang, B. Yao, Y. Wang, Y. Ju, and Y. Zhang, Chin. Opt. Lett. 5, 426 (2007).