Two-Photon Absorption Cross-Sections of Fluorene Derivatives with Cationic Substituents

Two novel fluorene derivatives having cationic substituents were synthesized. Two-photon absorption (TPA) properties of the derivatives were evaluated using the fluorescence-based technique with a femtosecond pulse emitted from a Ti:sapphire laser. Maximum TPA cross-sections of the compounds were estimated from the TPA spectra. TPA cross-sections of compounds with cationic substituents were found to be significantly larger than those of the compounds without cationic substituents.