December 07, 2006

Plasmons - bridging optics and electronics

New light physics with plasmons that could bridge light, matter and electronics. Plasmon computers could operate at 100 Terahertz - 1000 terahertz or 20,000 to 200,000 times faster than mainstream computer chips. Part of what I think is the growing trend of greater control of all information, light, energy, matter and magnetism. (ILEMM)

Two-dimensional light, or plasmons, can be triggered when light strikes a patterned metallic surface. Plasmons (wikipedia) may well serve as a proxy for bridging the divide between photonics (high throughput of data but also at the relatively large circuit dimensions of one micron, or one thousandth of a millimeter) and electronics (relatively low throughput but tiny dimensions of tens of nanometers, or millionths of a millimeter).

One might be able to establish a hybrid discipline, plasmonics, in which light is first converted into plasmons, which then propagate in a metallic surface but with a wavelength smaller than the original light; the plasmons could then be processed with their own two-dimensional optical components (mirrors, waveguides, lenses, etc.), and later plasmons could be turned back into light or into electric signals.

Plasmon microscope:

Igor Smolyaninov (University of Maryland, smoly@eng.umd.edu) reported that he and his colleagues were able to image tiny objects lying in a plane with spatial resolution as good as 60 nm (when mathematical tricks are applied, the resolution becomes 30 nm) using plasmons that had been excited in that plane by laser light at a wavelength of 515 nm. In other words, they achieve microscopy with a spatial resolution much better than diffraction would normally allow; furthermore, this is far-field microscopy -- the light source doesn't have to be located less than a light-wavelength away from the object.

This work is essentially a Flatland version of optics. They use 2D plasmon mirrors and lenses to help in the imaging and then conduct plasmons away by a waveguide.

Future plasmon circuits at optical frequencies:

Nader Engheta (University of Pennsylvania, engheta@ee.upenn.edu) argued that nano-particles, some supporting plasmon excitations, could be configured to act as nm-sized capacitors, resistors, and inductors -- the basic elements of any electrical circuit.

The circuit in this case would be able to operate not at radio (10**10 Hz) or microwave (10**12 Hz) frequencies but at optical (10**15 Hz) frequencies. This would make possible the miniaturization and direct processing of optical signals with nano-antennas, nano-circuit-filters, nano-waveguides, nano-resonators, and may lead to possible applications in nano-computing, nano-storage, molecular signaling, and molecular-optical interfacing.


More physics papers on plasmons

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