d transport information, analogous to electronics and photonics. Photonics has nearly unlimited bandwidth and almost no loss or dispersion, making it invaluable for high-throughput long-haul information networks. However, photonics components are diffraction-limited to micron-scale sizes, ruling out dense integration with nanoscale electronics. Plasmonics is potentially poised to bridge the tens of nanometer scale of modern electronics to the micron scale world of photonics. Many interesting devices, such as a 50nm metal-insulator-metal (MIM) surface plasmon waveguide capable of guiding 1.5um light even around 90o corners, have been proposed and are being actively investigated. Such devices have great promise, but also must overcome the limits imposed by the lossy propagation of surface plasmons in metals. The propagation lengths of surface plasmon waves in the visible and near infrared regimes are typically on the order of hundreds of microns on unpatterned surfaces, but drop to under thirty microns in sub-wavelength MIM waveguides. The propagation length in a modern optical fiber is drastically larger, on the order of kilometers. The small propagation lengths of surface plasmons are a significant hurdle in the practical implementation of plasmonics; however, researchers throughout the world are actively pursuing geometries which take account for this loss and new designs to limit the loss as much as possible.
Surface plasmons have many exciting potential applications and rich underlying physics drawing heavily from solid-state physics and electrodynamics. Although known for over 50 years, there are still many unsolved theoretical and experimental problems in the field of surface plasmons. Additionally, with the use of modern nanofabrication techniques, a whole range of new plasmonic devices have become possible. Although not without their drawbacks, surface plasmon based devices have a plethora of laboratory and commercial applications--including the potential to revolutionize photonic-electronic integration wi