Novel Heterocycle-Based Two-Photon Absorbing Dyes

The synthesis and nonlinear optical characterization of two novel heteroaromatic-based chromophores is described. The new dyes present an A−π−D−π−A general framework, where A is a π-deficient heteroaromatic ring (pyridine, quinoline, benzothiazole) and D a π-excessive pyrrolyl moiety. Both systems exhibit large two-photon absorption (TPA) values in the femtoseconds regime (TPA cross section as high as 150 × 10-50 cm4 s photon-1 molecule-1 with 150 fs laser pulses). Their TPA-based optical limiting activity is also shown.