Dynamical Theory of Spectral Diffusion

Abstract

The phenomenon of spectral diffusion (SD) was discovered in spin systems. It manifests itself in the dependence of dephasing time T₂ on the time delay τ between two laser pulses in experiments with microwave echo [97]. Klauder and Anderson [98] put forward a theory of stochastic type to explain the SD effect in spin systems. In their theory, a dipolar interaction between resonant spin and a huge number of off-resonant spins is a source of temporal line broadening. This approach underlies all theories developed later both for spin systems [99–101] and for optical spectra of chromophores [102–104]. In optical spectra, SD manifests itself through a temporal dependence of the optical line width or optical dephasing time T₂.