Influence of dephasing processes and temperature effects on transient hole-burning

Abstract

There has been a very rapid development in the experimental and theoretical treatments of ultrafast processes. Among all the spectroscopic techniques which enable us to understand the dynamics, as well as the mechanisms taking place between a molecule and its surrounding, transient hole-burning [1] holds the prospect of differentiating the homogeneous component resulting from very rapid interactions from the inhomogeneous conponent generated by the slowly varying interactions. Recently some limitations to transient hole-burning in the liquid phase have been identified [2]. For a narrow pump pulse, and a time delay short enough to avoid the influence of the spectral diffusion, the homogeneous linewidth is proportional to the hole width. If the spectral diffusion is rapid, the homogeneous contribution is then unobservable. Moreover, spectral congestion generates an overlaping of the holes corresponding to the vibrational structure. Also, Lauberau et al. [3] have developed and reported the application of picosecond time-resolved hole-burning to study the dynamics of inhomogeneous molecular systems in the infrared frequency domain. In their experiment, the pump and probe pulse overlap. Although previous description have taken into account the artifact contribution which comes from the overlap of the pulses, in the present work we shall give a theoretical description of ultrafast transient hole-burning to emphasize the effects of pure dephasing processes as well as temperature effects.