[1] [1] S. D. Liberato and C. Ciuti, Phys. Rev. Lett. 102, 136403 (2009).

[2] [2] M. O. Scully, Phys. Rev. Lett. 104, 207701 (2010).

[3] [3] M. Marthaler, Y. Utsumi and D. S. Golubev, Phys. Rev. Lett.107, 093901 (2011).

[4] [4] LIANG Ying, JIA Ke-ning, LIU Zhong-bo and FAN Xi-jun,Optoelectronics Lett. 8, 72 (2012).

[5] [5] C. L. Wang, Z. H. Kang, S. C. Tian, Y. Jiang and J. Y. Gao,Phys. Rev. A 79, 043810 (2009).

[6] [6] K. I. Osman, S. S. Hassan and A. Joshi, Eur. Phys. J. D 54,119 (2009).

[7] [7] V. Yannopapas, E. Paspalakis and V. Vitanovn, Phys. Rev. Lett. 103, 063602 (2009).

[8] [8] D. S. Wang and Y. J. Zheng, Phys. Rev. A 83, 013810 (2011).

[9] [9] LIANG Ying, JIA Ke-ning, LIU Zhong-bo and FAN Xi-jun,Journal of Optoelectronics Laser 22, 1886 (2011). (in Chinese)

[10] [10] X. J. Fan, Z. B. Liu, Y. Liang, K. N. Jia and D. M. Tong, Phys.Rev. A 83, 043805 (2011).

[11] [11] Z. B. Liu, L.Wang, Z.D. Wang, D. M. Tong and X. J. Fan,Optik 122, 150 (2011).

[12] [12] A. Hajibadali, K. Abbasian and Sh. Rahmatallahpur, Optik 123, 1035 (2012).

[13] [13] Y. L. Yang, L. Wang, Z. B. Liu, H. W. Lu and X. J. Fan, Acta Physica Sinica 58, 3161 (2009). (in Chinese)

[14] [14] Z. H. Xiao and K. Kim, Opt. Commun. 282, 2547 (2009).

[15] [15] X. J. Fan, B. Liang, Z. D. Wang and D. M. Tong, Opt. Commun.283, 1810 (2010).