Charge transfer-like interaction between organic dyes and aromatic molecules doped in amorphous polymer detected by incoherent photon echoes

Relaxation processes of dye molecules doped in polymer hosts have been understood by various kinds of interaction, such as the dipole-dipole interaction between molecules, the interaction with the two-level systems (TLS) in the host polymer and the electron-phonon interaction. The study on these interactions has been conducted to search for new efficient materials for the photonic device such as, for example, an optical memory. We present how the charge-transfer (CT)-like interaction between a donor and an acceptor molecule affect the dephasing property in the dye/polymer system. The CT-like interaction has not been investigated in dye-doped polymer system so far. We detect the effect of the CT-like interaction by using a degenerate four-wave-mixing technique (photon echoes) since it can conveniently probe the weak interactions between molecules as the change of the polarization decay rate. The sample system we employed is the cresyl violet (CV) doped polymers (polyvinyl alcohol (PVA) and polymethyl methacrylate (PMMA)), to which the nitrobenzene molecules are introduced to induce the interaction with the CV molecule.