[1] [1] B. Zhao, K. Duan, W. Zhao, C. Li, and Y. Wang, Chin. Opt. Lett. 8, 404 (2010).

[2] [2] X. Dong, H. Xiao, S. Xu, Z. Pan, Y. Ma, X. Wang, P. Zhou, and Z. Yang, Chin. Opt. Lett. 9, 111404 (2011).

[3] [3] C.Wirth, O. Schmidt, I. Tsybin, T. Schreiber, T. Peschel, F. Br¨uckner, T. Clausnitzer, J. Limpert, R. Eberhardt, A. T¨unnermann, M. Gowin, E. ten Have, K. Ludewigt, and M. Jung, Opt. Express 17, 1178 (2009).

[4] [4] D. C. Brown and H. J. Hoffman, IEEE J. Sel. Top. Quantum Electron. 37, 207 (2001).

[5] [5] Y. Wang, C. Q. Xu, and H. Po, IEEE Photon. Technol. Lett. 16, 63 (2004).

[6] [6] N. A. Brilliant and K. Lagonik, Opt. Lett. 26, 1669 (2001).

[7] [7] M.-A. Lapointe, S. Chatigny, M. Piche, M. Cain-Skaff, and J.-N. Maran, Proc. SPIE 7195, 719511 (2009).

[8] [8] Y. Fan, B. He, J. Zhou, J. Zheng, H. Liu, Y. Wei, Y. Dong, and Q. Lou, Opt. Express 19, 15162 (2011).

[9] [9] B. Zintzen, T. Langer, J. Geiger, D. Hoffmann, and P. Loosen, Opt. Express 15, 16787 (2007).

[10] [10] J. P. Gwinn and R. L. Webb, Microelectron. J. 34, 215 (2003).

[11] [11] J.W. Kim, D. Y. Shen, Jayanta K. Sahu, andW. Andrew Clarkson, IEEE J. Sel. Top. Quantum Electron. 15, 361 (2009).

[12] [12] P. Yan, A. Xu, and M. Gong, Opt. Eng. 45, 124201 (2006).