The influence of nuclear spin on theD 2 optical pumping of alkali metal vapors

We investigate theoretically a new way of producing laser light by means of parametric processes. For this end we treat Bose fields (photons, phonons, magnons, excitons etc.) which interact via nonlinear coupling and which are coupled individually to reservoirs. The action of the reservoirs alone would lead to a Gaussian distribution of the field amplitude. We solve the corresponding Fokker-Planck equation by a recently developed novel method and show that under certain conditions for the thermal photon numbers and decay constants a laser-like photon distribution may be found for the signal.