Proposed method for measuring the dephasing relaxation constant of excitonic molecules

Theoretical considerations of a method to measure the dephasing relaxation constant M of excitonic molecules are presented. The proposed method is based on the principle of the two-photon free-induction decay and makes use of an appropriate combination of polarizations of the incident light beams to eliminate the contribution from the excitonic polariton. It is demonstrated that the correlation trace of the signal is sensitive to the value of M and that a determination of M from the experiments is quite feasible.