Population redistribution induced by multiphoton processes
Ching Yin Fong, Y. Ron Shen · Journal of the Optical Society of America B · 1986
The effects of relaxation rates, dipole-matrix elements, level degeneracies, and detunings on the population redistribution induced by multiphoton processes have been studied theoretically in three- and four-level systems It is shown that a population inversion can always be established if the pumps have sufficiently high intensity Longitudinal relaxations and detunings appear to play more important roles in controlling the population distribution. The qualitative understanding achieved here can be extended to n levels with n-photon pumping.