Design of polymethine dyes with large third-order optical nonlinearities and loss figures of merit.
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.
Hales
Joel M
JM
School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, GA 30332, USA.
Matichak
Jonathan
J
Barlow
Stephen
S
Ohira
Shino
S
Yesudas
Kada
K
Brédas
Jean-Luc
JL
Perry
Joseph W
JW
Marder
Seth R
SR