[3] Tian G, Li J. Opt. Appl., 2013, 43(4): 803.
[4] Li J, Parchatka U, Fischer H. Appl. Phys. B, 2012, 108(4): 951.
[6] Leleux D P, Claps R, Chen W, et al. Appl. Phys. B, 2002, 74(1): 85.
[8] Meng Y X, Liu T G, Jiang J F, et al. IEEE Photonics Journal, 2014, 6(6): 6803209.
[9] Reid J, Labrie D. Appl. Phys. B, 1981, 26: 203.