[1] [1] C. Schori, G. Mileti, B. Leuenbeger, and P. Rochat, in Proceedings of the Europen Frequency and Time Forum 13 (2010).

[2] [2] T. Zanon, S. Tremine, S. Guerandel, F. Dahes, E. De Clercq, A. Clairon, and N. Dimarcq, in Proceedings of the 2005 IEEE International Frequency Control Symposium and Exposition 774 (2005).

[3] [3] S. T. Muller, D. V. Magalhaes, A. Bebeachibuli, T. A. Ortega, M. Ahmed, and V. S. Bagnato, J. Opt. Soc. Am. B 25, 6 (2008).

[4] [4] F. X. Esnault, S. Perrin, S. Tremine, S. Guerandel, D. Holleville, N. Dimarcq, V. Hermann, and J. Delporte, in Proceedings of Joint Conference of the 2007 IEEE International Frequency Control Symposium and the 21st European Frequency and Time Forum 1327 (2007).

[5] [5] D. Lv, B. Wang, T. Li, and L. Liu, Chin. Opt. Lett. 8, 735 (2010).

[6] [6] S. J. J. M. F. Kokkelmans, B. J. Verhaar, K. Gibble, and D. J. Heinzen, Phys. Rev. A 56, 6 (1997).

[7] [7] J. C. Berengut, V. V. Flambaum, and E. M. Kava, Phys. Rev. A 84, 042510 (2011).

[8] [8] S. N. Lea, Eur. Phys. J. Special Topics 63, 374 (2008).

[9] [9] E. A. Burt, S. Taghavi-Larigani, and R. L. Tjoelker, Phys. Rev. A 79, 062506 (2009).

[10] [10] S. Fray, C. A. Diez, T. W. Hansch, and M. Weitz, Phys. Rev. Lett. 93, 240404 (2004).

[11] [11] S. B. Papp and C. E. Wieman, Phys. Rev. Lett. 97, 180404 (2006).

[12] [12] H. Chen, W. Cai, W. Shu, F. Li, and Y. Wang, Chinese J. Lasers (in Chinese) 21, 280 (1994).

[13] [13] H. Ma, H. Cheng, W. Zhang, L. Liu, and Y. Wang, Acta Phys. Sin. (in Chinese) 58, 1569 (2009)

[14] [14] H. Cheng, W. Zhang, H. Ma, L. Liu, and Y. Wang, Phys. Rev. A 79, 023407 (2009).

[15] [15] W. Zhang, X. Wang, H. Cheng, L. Xiao, L. Liu, and Y. Wang, Chin. Phys. Lett. 26, 8 (2009).

[16] [16] L. Xiao, X. Wang, W. Zhang, H. Cheng, L. Liu, and Y. Wang, Chin. Opt. Lett. 8, 3 (2010).

[17] [17] X. Wang, H. Cheng, B. Zheng, Y. Meng, L. Xiao, L. Liu, and Y. Wang, in Proceedings of 2011 Joint Conference of

[18] [18] the IEEE International Frequency Control and the European Frequency and Time Forum 1 (2011).

[19] [19] C. Monroe, W. Swann, H. Robinson, and C. Wieman, Phys. Rev. Lett. 65, 13 (1990).

[20] [20] G. Santarelli, C. Audoin, A. Makdissi, P. Laurent, G. J. Dick, and A. Clairon, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 45, 4 (1998).