Theoretical treatment of the effects of external pulse field on the emission and absorption of two impurity centers has been attempted. Good overlapping of emission band of one center (donor of energy) with the absorption band of another center (acceptor of energy) is assumed, so that radiative and non-radiative energy transfer may take place. Mathematical model is based on the system of reduced Maxwell equations for magnitudes of field components and Bogolubov's equations for elements of multiparticle density matrix of donor-acceptor complex. Numerical solution is obtained for NaCl:Cu, Mn and KCl:Pb,Eu crystals. These materials are differing in the value of transition dipole moment of acceptor absorption. It is low for the first medium while for KCl:Pb,Eu it is comparable to that one for the donor emission. It turns out that in the case of low value of transition dipole moment the luminescence of both components of donor-acceptor pair takes place. On the contrary, only acceptor emission exists in the case of high value of transition dipole moment of acceptor when the pump intensity is low. Simultaneous luminescence of donor and acceptor occurs when pump intensity is enough. So, in the systems of such kind the emission may be changed over from one frequency to another through the power level of pump radiation.

Date Published: 26 May 1999
PDF: 7 pages
Proc. SPIE 3610, Laser Material Crystal Growth and Nonlinear Materials and Devices, (26 May 1999); doi: 10.1117/12.349233

Published in SPIE Proceedings Vol. 3610:
Laser Material Crystal Growth and Nonlinear Materials and Devices
Kathleen I. Schaffers; Lawrence E. Myers, Editor(s)