23 December 2008
âSurface plasmon-polaritonsâ â essentially light waves trapped on the surface of a metal â are expected to form the basis of numerous next-generation chip-scale technologies.
Now, a team led by researchers from the University of Southamptonâs Optoelectronics Research Centre has demonstrated experimentally that the propagation of such signals can be optically controlled on the femtosecond timescale.
âPlasmonicâ technologies, which exploit surface plasmon-polaritons as information carriers, have attracted considerable attention in recent years because they have the potential to combine the small size of todayâs micro/nanoelectronic devices with the speed and bandwidth of fibre-optic data transmission systems. In so doing, they would enable a new generation of smaller, faster, more efficient devices. However, if this potential is to be realized, techniques for actively switching plasmonic signals are required, and those developed so far are unlikely to satisfy the demands of future applications in such fields as high-speed data processing.
In a paper just published in Nature Photonics, Professor Nikolay Zheludev, Dr Kevin MacDonald and graduate student Zsolt Samson describe how propagating plasmonic signals can be modulated on the femtosecond timescale. Laser pulses are used to momentarily modify the properties of the metal surface supporting the surface plasmon-polariton, and thereby to achieve signal switching speeds several orders of magnitude faster than existing technologies. Dr. MacDonald comments: âThe ultrafast switching times and modest energy requirements of this technique open the gates to the exploration of what can ultimately be achieved in plasmonic switching. We believe that such studies will inform the future development of technologically relevant device structures in the same way that studies of ultrafast optical phenomena have contributed to the advancement of todayâs fibre-based telecommunications networks.â?
A copy of the paper is available at: http://dx.doi.org/10.1038/NPHOTON.2008.249
Authored by Dr Kevin MacDonald