Fourier-transform spectroscopy in dye-doped polymers using the femtosecond accumulated photon echo

Abstract
Fourier-transform spectroscopy using the technique of femtosecond accumulated photon echo with incoherent light has been performed in dye-doped polymers. Several types of interference effect or quantum beat between the zero-phonon line and other spectral components including the phonon sideband, the vibronic lines, and the photoproduct state have been observed. Based on the density matrix incorporating the transition-frequency modulation, it is pointed out that the factorization approximation for the relaxation function holds rigorously in the accumulated photon echo. We also clarified that the Fourier cosine transform of the heterodyne-detected echo signal provides the hole-burning spectrum.