S. J. D. Phoenix, and T. J. Shepherd, Phys. Rev. A 42 , 4102 (1990); P. Domokos, P. Horak, and H. Ritsch, ibid. 65 , 033832 (2002). [30] Fam Le Kien, S. Dutta Gupta, V. I. Balykin, and K. Hakuta, Phys. Rev. A 72 , 032509 (2005). [31] F. De Martini, M. Marrocco, P. Mataloni, L. Crescentini, and R. Loudon Phys. Rev. A 43 , 2480 (1991). [32] G. Bj¨ ork and Y. Yamamoto, in Spontaneous Emission and Laser Oscillations in Microcavities , edited by H. Yokoyama and K. Ujihara (CRC press, New York, 1995), p. 189. [33] R. J. Cook and P. W. Milonni, Phys. Rev. A 35 , 5081 (1987). [34] D. F. Walls and G. J. Milburn, Quantum Optics (Springer, New York, 1994). [35] R. Loudon, The Quantum Theory of Light (Oxford, New York, 2000); L. Mandel and E. Wolf, Optical Coherence and Quantum Optics (Cambridge, New York, 1995). 22