 
Summary: Validity of rate equations for Zeeman coherences for analysis of nonlinear interaction
of atoms with broadband laser radiation
Kaspars Blushs and Marcis Auzinsh
Department of Physics, University of Latvia, 19 Rainis Blvd., Riga LV1586, Latvia
(Received 27 December 2003; published 9 June 2004)
In this paper we obtain the rate equations for Zeeman coherences in the broadline approximation and
steadystate balance equations directly from optical Bloch equations without the use of the perturbation theory.
The broadline approximation allows us to use the adiabatic elimination procedure in order to eliminate the
optical coherences from the optical Bloch equations, but the steadystate condition allows us to derive the
balance equations in a straightforward way. We compare our approach with the perturbationtheory approach as
given previously and show that our approach is more flexible for analyzing various experiments. Meanwhile
we also show the validity and limitations of the application of the rate equations in experiments with coherent
atomic excitation when either the broadline approximation or steadystate conditions hold. Thus we have
shown the basis for modeling the coherent atomic excitation experiments by using the relatively simple rate
equations, provided that certain experimental conditions hold.
DOI: 10.1103/PhysRevA.69.063806 PACS number(s): 42.50.Gy, 32.80.Bx, 32.60. i
I. INTRODUCTION
Coherent effects in the interaction of laser radiation with
atoms and molecules play a major role in physics and chem
istry. Applications such as electromagnetically induced trans
