EFFECTS OF COOPERATIVE ATOMIC INTERACTIONS IN A SINGLE-MODE LASER

An analysis of cooperative atomic interaction in atom-field interaction is presented. A complete exact solution to the problem of two two-level atoms interaction with a single-mode quantized radiation field, in a high-Q cavity, is given. Effects of cooperation on total population inversion of two atoms as well as on the population inversion of single atom in the presence of another atom are studied. Interaction of two two-level atoms with a vacuum field in a damped cavity is studied. Numerical solutions are presented and it is shown that for asymmetric coupling there are significant effect on the dynamics of atomic inversion. It is also shown that in contrast with symmetric atom-field coupling case, there is a retention of energy by the atom when the other atom couples with different strength.\ud \ud An extension of Scully-Lamb theory is made by the inclusion of cooperative atomic interactions. In particular, the single- and two-atom interactions with the field are included. A non-perturbative treatment is used to examine the effects of cooperative atomic interactions on the photon statistics in a single-mode laser. It is shown that cooperative interactions do increase the photon number fluctuations. Our results are valid for all range of laser parameters. Effect of cooperative interactions is analysed on the natural linewidth of a single-mode laser. It is shown that cooperative interactions tend to decrease the natural linewidth under certain conditions