Synthesis, characterization and optical properties of a new heterocycle-based chromophore

A new heterocycle-based two-photon absorption chromophore, 4-[4-(4,5-diphenyl-1H-imidazol-2-yl)styryl]pyridine (DIYSP), has been synthesized and characterized. The molecule possesses an A–π–A′ structure. The π-deficient heteroaromatic ring (4,5-diphenyl-1H-imidazole) is used as an acceptor (A), and the pyridine ring is used as another acceptor (A′). Pumped with 740 nm laser excitation, DIYSP had a two-photon absorption cross-section 41 GM (1 GM = 1 × 10−50 cm4 s photon−1) and a two-photon excited fluorescence 511 nm in DMF, respectively. A microstructure using DIYSP as an initiator has been fabricated under irradiation of 80 fs, 80 MHz Ti:sapphire femtosecond laser at 800 nm. The possible mechanism of photopolymerization is discussed.