Noncoherent four-photon parametric processes

An analysis is made of the excitation of a four-photon parametric process by a noncoherent Gaussian (noise) pump field. An allowance is made for the dispersive and dissipative properties of the nonlinear medium. It is shown that this process may have a fairly high efficiency in vapors of Cd, Hg, and Zn metal atoms if rare gas fluoride excimer laseres are used as pump sources.