Acta Optica Sinica
Photon statistics for two-photon processes
HE Long-qing
Abstract
The photon statistic of two-photon processes is treated for the general case of two-level systems. After generalizing the generating-function method, we derived the generating function with parameter r (atomic population ratio), its partial differential equation, and equations of factoril moments as well as equations of correlation functions. Analytical solutions were obtained for various values of r. Curves of n and g(2) versus τ and r were deduced for three kinds of initial fields. Both the effect of r on photon antibunching and characteristics photon statistics for two-photon amplifiers are discussed. The photon superbunching is proposed as one of the criteria for two-photon amplification.