1. cf. G. S. Agarwal, “Quantum Optics,” Springer Tracts in Modern Physics, Vol. 70, G. Hühler, ed., Springer, Berlin (1974).
2. R. E. Benner, P. W. Barber, J. F. Owen and R. K. Chang, Phys. Rev. Lett. 44:475 (1980)
3. W. H. Weber and C. F. Eagen, Opt. Lett. 4: 236 (1979).
4. A. G. Vaidyanathan, W. P. Spencer and D. Kleppner, Phys. Rev. Lett.47: 1592 (1982).
5. G. S. Agarwal and S. V. Oneil, Phys. Rev. B. 28:xxx (1983); ibid85b: 301 (1978).