Anomalous continuous-time random-walk spectral diffusion in coherent third-order optical response.
Recursive relations are derived for nonlinear optical response functions of a two-level chromophore with stochastic frequency fluctuations described by a continuous-time random walk. Stationary ensembles are constructed and signatures of anomalous relaxation in the photon echo signal are discussed for a two state jump modulation with a power law waiting time density function psi(t) approximately t(-alpha-1). Stretched exponential decay of the photon echo signal is predicted for 0<alpha<1 and power law asymptotics for 1<alpha<2.
Department of Chemistry, University of California, Irvine, CA 92697, USA.
Frantisek
F
Sanda
Shaul
S
Mukamel