Quantum statistics of field after double-beam two-photon absorption

Two-photon absorption for a collection of unexcited two-level atoms from two beams of light is considered and the statistical properties of the beams after the interaction are investigated. The dynamical behaviour of the beams is described by assuming the atoms maintained with a nearly fixed population distribution. By applying iteration methods the time development for the paired generating functional of the field is obtained and by means of this generating functional paired modal densities are written. The modal densities are then used for discussing the statistical properties of light after the interaction.