title: Aggregates of quadrupolar dyes: giant two-photon absorption from biexciton states.
abstract: A model for aggregates of quadrupolar (DAD or ADA) molecules is presented that relaxes the dipolar approximation for intermolecular electrostatic interactions. New effects, including the appearance of bound biexcitons in clusters of nonpolar molecules, are predicted with interesting and unforeseen consequences on the material properties. Specifically, we show that the large two-photon absorption cross-section, typical of quadrupolar chromophores, can be further amplified by orders of magnitude as a result of aggregation.
authors.affiliation: Dipartimento di Chimica GIAF & INSTM UdR di Parma, Università di Parma, Parco Area delle Scienze 17/a, 43100 Parma, Italy.
authors.forename: Gabriele
authors.initials: G
authors.lastname: D'Avino
authors.forename: Francesca
authors.initials: F
authors.lastname: Terenziani
authors.forename: Anna
authors.initials: A
authors.lastname: Painelli