Tracing coherences of quantum states by ultrafast laser spectroscopy

Abstract

An overview of the influence of coherent coupling in light–matter interaction traced by transients in pumpprobe spectroscopy is given, with special emphasis on interest and works provided by the authors. Advantages of this technique used to trace pathways of transfer and decay of quantum coherences in atoms, molecular aggregates, and biological structures, as well as feasibility of the probing of both the lifetime and characteristic lengths (area, volume) of coherent excitations are discussed. Theoretical analysis of the pump-probe measurements is based on the numerical solution of the equation for the reduced density matrix in the representation of atomic, molecular, and excitonic states, considering coherent coupling between light and appropriate quantum states precisely.