title: Design of polymethine dyes with large third-order optical nonlinearities and loss figures of merit.
abstract: All-optical switching applications require materials with large third-order nonlinearities and low nonlinear optical losses. We present a design approach that involves enhancing the real part of the third-order polarizability (gamma) of cyanine-like molecules through incorporation of polarizable chalcogen atoms into terminal groups, while controlling the molecular length to obtain favorable one- and two-photon absorption resonances that lead to suitably low optical loss and appreciable dispersion enhancement of the real part of gamma. We implemented this strategy in a soluble bis(selenopyrylium) heptamethine dye that exhibits a real part of gamma that is exceptionally large throughout the wavelength range used for telecommunications, and an imaginary part of gamma, a measure of nonlinear loss, that is smaller by two orders of magnitude. This combination is critical in enabling low-power, high-contrast optical switching.
authors.affiliation: School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, GA 30332, USA.
authors.forename: Joel M
authors.initials: JM
authors.lastname: Hales
authors.forename: Jonathan
authors.initials: J
authors.lastname: Matichak
authors.forename: Stephen
authors.initials: S
authors.lastname: Barlow
authors.forename: Shino
authors.initials: S
authors.lastname: Ohira
authors.forename: Kada
authors.initials: K
authors.lastname: Yesudas
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Brédas
authors.forename: Joseph W
authors.initials: JW
authors.lastname: Perry
authors.forename: Seth R
authors.initials: SR
authors.lastname: Marder