Atlanta, GA--A new type of organic optical molecule could provide the demanding combination of properties needed to serve as the foundation for low-power, high-speed all-optical signal processing.1
All-optical switching could allow large speed increases in telecommunications (from today’s speeds of less than 100 Gbit/s to as high as 2000 Gbit/s) by eliminating the need to convert photonic signals to electronic signals and back for switching. All-optical processing could also facilitate photonic computers with similar speed advances.
Polymethine organic dye materials developed by a team at the Georgia Institute of Technology combine large nonlinear properties, low nonlinear optical losses, and low linear losses. Materials with these properties are essential if optical engineers are to develop a new generation of devices for low-power and high-contrast optical switching of signals at telecommunications wavelengths. Keeping data all-optical would greatly facilitate the rapid transmission of detailed medical images, development of new telepresence applications, high-speed image recognition, and even the fast download of high-definition movies.
Now in solution, next as a solid
But the favorable optical properties possessed by these new materials have only been demonstrated in solution. For their materials to have practical value, the Georgia Tech researchers will have to incorporate them in a solid phase for use in optical waveguides--and address a long list of other challenges.
Seth Marder, Joseph Perry, and their collaborators in Georgia Tech's Center for Organic Photonics and Electronics have been working on the molecules for several years, refining their properties and adding atoms to maximize their length without inducing symmetry breaking, a phenomenon in which unequal charges build up within molecules. This molecular design effort, which builds on earlier research with smaller molecules, included both experimental work and theoretical studies done in collaboration with Jean-Luc Bredas, a professor in the School of Chemistry and Biochemistry.
"For this class of molecules, we can with a high-degree of reliability predict where the molecules will have both large optical nonlinearities and low two-photon absorption," said Marder. "Not only can we predict that, but, using well-established chemical principles, we can tune where that will occur such that if people want to work at telecommunications wavelengths, we can move to where the molecules absorb to optimize its properties."
The researchers emphasize that many years of research remain ahead before their new materials will be practical.
REFERENCE
1. Joel M. Hales et al., Science Express Reports, published online February 18 2010; 10.1126/science.1185117.
