[Audio] NCN Nanophotonics: Research Seminars

Performance of optical delay lines and nonlinear devices based on slow wave propagation in photonic crystal waveguides in the presence of higher order dispersion is analyzed and compared with other slow light schemes, such as coupled resonators, media with electromagnetically-induced transparence, surface plasmons, and optical amplifiers. It is shown that higher order dispersion of gain and index severely limits the bit rate of the system. Novel methods for increasing the bit rate are proposed and analyzed. These methods range from mundane dispersion-compensation schemes to the most elaborate methods using adiabatic changes and various parametric processes. The conclusion is that the slow light is definitely anything but a “silver bullet” for most purported applications, there still might be a practical niche for it.

Surface plasmon-polaritons (or plasmons) are collective excitations of the conduction electrons and the electromagnetic field on the surface of such good metals as gold and silver. Near the frequency of surface plasmon resonance plasmons may perceive regular dielectrics as negative index metamaterials. As a result, unusual microscopy, lithography, and waveguiding devices may be realized. Nonlinear optics of these metamaterials is also extremely interesting. I will de- scribe recent experiments on plasmon-induced inverse Faraday effect in plasmonic metamateri- als. The plasmonic control of the spins opens new interesting avenues for all-optical ultrafast control of the magnetization at a nanometer length scale.

The silicon chip has been the mainstay of the electronics industry for the last 40 years and has revolutionized the way the world operates. Today a silicon chip the size of a fingernail contains nearly one billion transistors and has the computing power that only a decade ago would take up an entire room of servers. Silicon photonics that mainly based upon silicon on insulator (SOI) has recently attracted a great deal of attention since it offers an opportunity for low cost opto-electronic solutions for applications ranging from telecommunications down to chip-to-chip interconnects as well as possible applications in new emerging areas such as optical sensing and or bio-medical applications. Recent advances and research breakthroughs in silicon photonic device performance over the last few years have shown that silicon can be considered as a material onto which one can build future optical devices. While significant efforts are needed to improve device performance and to “commercialize” these technologies, progress is moving at a rapid rate. If successful, silicon photonics may similarly come to dominate the optical communications industry as it has the electronics industry. The presentation will provide overview of silicon photonics research at Intel Corporation, describe some of the recent advances in device performance and discuss the key building blocks needed for “siliconizing” photonics. In addition the presentation will provide an overview and discussion on the potential applications and future opportunities for silicon photonics.

Nematic liquid crystals support optical spatial solitons via light-induced molecular reorientation. Such all-optical waveguides can channel a signal towards a destination, hence permitting signal routing. Owing to the inherent anisotropy of nematic liquid crystals, molecular orientation and birefringent walk-off can be electro-optically adjusted, leading to voltage-tunable steering and signal readdressing. Combined with the presence of a dielectric interface, this voltage-control can be exploited for refraction as well as total intenal reflection of spatial solitons, reaching unprecedented angular deviations of as much as 40°.

As nanonphotonics and nanoelectronics are pushed down towards the molecular scale, interesting effects emerge. We discuss how birefringence (different propagation of two polarizations) is manifested and could be useful in the future for two systems: coherent plasmonic transport of near-field light and spin-birefringence.

Gold nanorods have several outstanding characteristics as optical contrastagents for biomedical imaging. Their strong optical absorption atnear-infrared (NIR) frequencies can be used to generate contrast for opticalcoherence tomography (OCT) imaging, and is well matched for detectionmodalities based on differential albedo. Nanorods can also be imageddirectly by two-photon luminescence (TPL) with single-particle sensitivity,and are sufficiently bright to support in vivo imaging applications. TPLimaging has been used to study the uptake of ligand-functionalized nanorodsby tumor cells. Lastly, nanorods are excellent converters of light energyinto heat, with direct application in photothermal therapy.