CAVITY POLARITONS BEYOND THE BOSON APPROXIMATION

By applying a transformation from fermion pair operators to boson oper ators which preserves the Fermi commutation rules for exciton operator s, we introduce the correlation effects neglected in the crude boson a pproximation. We apply this method to describe saturation effects in c avity polaritons under resonant optical pumping. The reduction in Rabi splitting with increasing pump intensity and the non-linear behaviour of the input-output characteristics are described. Finally, by applyi ng the linearized theory of fluctuations, we obtain an analytic expres sion for the normalized second-order correlation function for the tran smitted light which exhibits photon antibunching even in the limit of weak pump power. The photon antibunching behaviour is inversely propor tional to the number of states available for exciton formation.