[2] Chen Y F, Zhuang W Z, H. C. Liang H C, et al. Laser Physics Letters, 2013, 10(1): 015803.

[3] Lagatsky A A, Sarmani A R, Brown C T A, et al. Optics Letters, 2005, 30(23): 3234.

[4] Zhuang W Z, Chang M T, Liang H C, et al. Optics Letters, 2013, 38(14): 2596.

[5] Li W, Hao Q, Zhai H, et al. Opt. Express, 2007, 15(5): 2354.

[6] Zhu J, Tian W, Wang J, et al. Optics Letters, 2012, 37(24): 5190.

[7] Yang Q, Liu J, Fan X W, et al. Laser Physics, 2012, 22(5): 896.

[8] Liu J, Wan Y, Tian X, et al. Applied Physics B, 2013, 111(2): 233.

[9] Xue Y H, Wang C Y, Li J, et al. IEEE Journal, 2008, 44(7): 686.

[10] Siebold M, Bock S, Schramm U, et al. Applied Physics B, 2009, 97(2): 327.

[11] Machinet G, Sevillano P, Guichard F, et al. Optics Letters, 2013, 38(20): 4008.

[12] Ricaud S, Georges P, Camy P, et al. Applied Physics B, 2012, 106(4): 823.

[13] Basiev T T, Vasil’ev S V, Doroshenko M E, et al. Quantum Electronics, 2007, 37(10): 934.

[14] Su L B, Xu J, Li H J, et al. Optics Letters, 2005, 30(9): 1003.

[15] Basiev T T, Doroshenko M E, Fedorov P P, et al. Optics Letters, 2008, 33(5): 521.

[17] Liu J, Feng C, Su L B, et al. Laser Physics Letters, 2013, 10(10): 105806.

[18] Wu Y Q, Su L B, Wang Q G, et al. Laser Physics, 2013, 23(10): 105805.