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Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE

Manipulation of spectra of output radiation of dopant energetic donor-acceptor pair by pump light power

A E Dmitriev, Yelena I. Dmitriyeva, Oleg M. Parshkov, Nina E. Popova

Published May 26, 1999• 1 citation

Abstract

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.

DOI: 10.1117/12.349233

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The coherent energy transfer efficiency of a pair of two-level atoms is studied theoretically and its mathematical expression has been deduced. The problem of atoms coherent energy transfer theory is treated by quantum perturbation theory and equivalent method replacing atomic dipole field with light field of the same frequency. The detuning between the donor atom transition frequency and the acceptor atom transition frequency has been studied in the theory. With the increase of the detuning of the two-atomic transition frequency, the energy transfer efficiency decays rapidly. In the case of two-atomic transition frequency resonance, the coherent resonance energy transfer efficiency is directly proportional to the square of the sine of the minus three power of the distance between two atoms and the energy transfer efficiency is periodically decaying over time. The coherent resonance energy transfer efficiency is inversely proportional to the six power of the distance between the two atoms in the first-order approximation.