| Abstract: | In this paper, the density matrix formalism has been applied to treat ultrafast time-resolved absorption spectroscopy. We have shown that in the femto-second (fs) pump-probe experiments, the observed time-resolved absorption spectra consist of the contributions from the population (i.e., incoherent contribution) and the coherence (i.e., the phase of the system). The adiabatic approximation has been used to derive the expressions for ultrafast time-resolved spectra. We have also shown that the dynamics of the coherence will result in quantum beat. Numerical calculations have been performed to demonstrate the theoretical results. |
