[1] [1] X. R. Hou, S. M. Zhou, Y. K. Li, and W. J. Li, Opt. Mater. 32, 1435 (2010).

[2] [2] J. R. Lu, J. H. Lu, T. Murai, K. Takaichi, T. Uematsu, K. Ueda, H. Yagi, T. Yanagitani, and A. A. Kaminskii, Jpn. J. Appl. Phys. 40, 1277 (2001).

[3] [3] A. Ikesue and Y. L. Aung, Nat. Photonics 2, 721 (2008).

[4] [4] Y. B. Wang, B. S. Wang, Y. Bao, J. L. Xu, S. Song, X. J. Peng, Z. Y. Xu, W. B. Liu, and Y. B. Pan, Chin. Opt. Lett. 8, 1144 (2010).

[5] [5] H. Cai, J. Zhou, H. Zhao, Y. Qi, Q. Lou, J. Dong, and Y. Wei, Chin. Opt. Lett. 6, 852 (2008).

[6] [6] Y. Qi, Q. Lou, H. Ma, and J. Dong, Chin. Opt. Lett. 3, 89 (2005).

[7] [7] B. Jiang, T. Huang, Y. Wu, W. Liu, and Y. Pan, Chin. Opt. Lett. 7, 505 (2009).

[8] [8] J. H. Mun, A. Jouini, A. Novoselov, Y. Guyot, A. Yoshikawa, H. Ohta, H. Shibata, Y. Waseda, G. Boulon, and T. Fukuda, Opt. Mater. 29, 1390 (2007).

[9] [9] Y. Guyot, R. Moncorgd, L.D. Merkle, A. Pinto, B. McIntosh, and H. Verdun, Opt. Mater. 5, 127 (1996).

[10] [10] F. S. Ermeneux, C. Goutaudier, R. Moncorge, M. T. Cohen-Adad, M. Bettinelli, and E. Cavalli, Opt. Mater. 8, 83 (1997).

[11] [11] R. L. Fullman, Trans. Am. Instit. Min. Metal. Eng. 197, 1267 (1953).

[12] [12] P. L. Chen and I. W. Chen, J. Am. Ceram. Soc. 79, 1801 (1996).

[13] [13] W. T. Carnall, P. R. Fields, and B. G. Wybourne, J. Chem. Phys. 42, 3797 (1965).

[14] [14] B. M. Walsh, N. P. Barnes, and B. D. Bartolo, J. Appl. Phys. 83, 2772 (1998).

[15] [15] C. Y. Tu, J. F. Li, Z. J. Zhu, Z. Q. Chen, Y. Wang, and B. C. Wu, Opt. Commun. 227, 383 (2003).

[16] [16] D. C. Zhou, R. F. Wang, Z. W. Yang, Z. G. Song, Z. Y. Yin, and J. B. Qiu, J. Non-Crystal. Solids 357, 2409 (2011).

[17] [17] R. Xu, Y. Tian, L. Hu, and J. Zhang, Appl. Phys. B 104, 839 (2011).

[18] [18] E. Husson, C. Proust, P. Gillet, and J. P. Itie, Mater. Res. Bull. 34, 2085 (1999).