Photoinduced Quantum Interference Antiresonances in [Formula presented]-Conjugated Polymers

We observed photoinduced quantum interference antiresonances between several discrete infrared-active vibrations and the lower-polaron continuous absorption band in a series of [Formula presented]-conjugated polymer films having superior planar orders, where the polaron transition energy is relatively small. The photoinduced Fano-type antiresonances are well explained by extending the amplitude mode model beyond the adiabatic limit. The agreement between the data and the model confirms the presence of a continuous electronic band above the polaron state. We show that high frequency modes are strongly coupled to electrons, with implications for superconductivity.