[1] Z. Liu, B. Liu, Z. Li, Z. Yan, S. Wu, and Z. Sun, Appl. Phys. B 88, 327 (2007).

[2] J. Hair, C. Hostetler, A. Cook, D. Harper, R. Ferrare, T. Mack, W. Welch, L. Lzquierdo, and F. Hovis, Appl. Opt. 47, 6734 (2008).

[3] O. Reitebuch, C. Lemmerz, E. Nagel, U. Paffrath, Y. Durand, M. Endemann, F. Fabre, and M. Chaloupy, J. Atmos. Oceanic Technol. 26, 2501 (2009).

[4] L. Tang, Z. Shu, J. Dong, Gu. Wang, Y. Wang, W. Xu, D. Hu, T. Chen, X. Dou, Do. Sun, and H. Cha, Chin. Opt. Lett. 8, 726 (2010).

[5] Z. Li, C. Lemmerz, U. Paffrath, O. Reitebuch, and B. Witschas, J. Atmos. Oceanic Technol. 27, 693 (2010).

[6] Z. Wang, Z. Liu, L. Liu, S. Wu, B. Liu, Z. Li, and X. Chu, Appl. Opt. 49, 6960 (2010).

[7] F. Hovis, M. Rhoades, R. Burnham, J. Force, T. Schum, B. Gentry, H. Chen, S. Li, J. Hair, A. Cook, and C. Hostetler, Proc. SPIE 5332, 263 (2004).

[8] T. Schroeder, C. Lemmerz, O. Reitebuch, M. Wirth, C. Wuehrer, and R. Treichel, Appl. Phys. B 87, 437 (2007).

[9] F. Hovis, J. Edelman, T. Schum, J. Rudd, and K Andes, Proc. SPIE 6871, 68710E (2008).

[10] J. Zhou, H. Zang, D. Liu, X. Zhu, J. Liu, and W. Chen, in Proceedings of 24th International Laser Radar Conference S01P 27 (2008).

[11] S. Henderson, E. Yuen, and E. Fry, Opt. Lett. 11, 715 (1986).

[12] S. Henderson, “Single frequency operation of Nd:YAG laser”, Ph. D. Thesis (Texas A&M University, 1986).

[13] V. Evtuhov and A. Siegman, Appl. Opt. 4, 142 (1965).

[14] J. Wang, J. Zhou, H. Zang, X. Zhu, and W. Chen, Chin. Opt. Lett. 8, 670 (2010).

[15] J. Wang, R. Zhu, J. Zhou, H. Zang, X. Zhu, and W. Chen, Chin. Opt. Lett. 9, 081405 (2011).