Transport and correlated fluctuations in the nonlinear optical response of excitonsD. Abramavicius1, L. Valkunas2, 3 and S. Mukamel1
1 Chemistry Department, University of California Irvine - 1102 Natural Sciences 2, Irvine, CA 92697-2025, USA
2 Theoretical Physics Department, Faculty of Physics of Vilnius University - Sauletekio ave. 9, bld. 3, Vilnius, LT 10222, Lithuania
3 Institute of Physics - Savanoriu 231, Vilnius, LT 02300, Lithuania
received 26 March 2007; accepted in final form 13 August 2007; published October 2007
published online 7 September 2007
Closed expressions are derived for the femtosecond four-wave mixing of excitons which include slow Gaussian diagonal fluctuations (spectral diffusion) through the cumulant expansion and incoherent exciton transport induced by fast Markovian fluctuations. The interplay of both processes in the two-dimensional photon echo is demonstrated using model calculations for a dimer.
78.47.+p - Time-resolved optical spectroscopies and other ultrafast optical measurements in condensed matter.
82.53.Kp - Coherent spectroscopy of atoms and molecules.
33.70.Jg - Line and band widhs, shapes, and shifts.
© Europhysics Letters Association 2007