Enhanced two photon absorption cross section and optical nonlinearity of a quasi-octupolar molecule

Abstract Two photon absorption (2PA) cross sections of two quasi-octupolar molecules ( E , E , E )-2,4,6-tris [2-(4- N , N -diphenylaminophenyl)vinyl]pyridine (DPATSP) and (2,4,6-tris(( E )-4-(diphenylamino)styryl)-1-methylpyridine-1-ium iodide, DPATSP-Me) have been estimated. It has been found that by introducing the pyridinium ion, the 2PA cross section of DPATSP-Me increases with respect to the parent molecule, DPATSP. Z-scan experiments on the two samples reveal that DPATSP-Me is a better candidate for optical limiting applications.