Researchers Present Method for Controlling Light with Plasmon Waves

Researchers Present Method for Controlling Light with Plasmon Waves

25 April 2013

A Harvard-led research team has developed a nanoscale device that transforms optical signals into surface plasmon polaritons and has the ability to discern between the movements of polarized light and control the signals' directions without destroying them, reports.

For the purposes of the experiment, researchers from the Harvard School of Engineering and Applied Sciences (SEAS) and colleagues from Singapore and China developed two devices with a herringbone design: a rectangular array and a ring-shaped array. The team then distributed to the two devices circularly polarized light with waves that travel in opposite directions. In the case with the ring-shaped coupler, plasmons were infused either away or toward the center of the mechanism, allowing intensity at the center of the ring to be turned on and off by controlling the polarization of the light. The coupler converted the incoming light into waves, known as surface plasmon polaritons - electromagnetic waves trapped at or guided along metal-dielectric interfaces. This technology, which enables a change in the direction of surface plasmon polaritons, could help in the creation of a new type of on-chip optical interconnect that can successfully channel information from optical to electronic devices. So far, the direction of the waves could be manipulated only by changing the angle of the light that reaches the surface of the coupler.

Balthasar Müller, SEAS graduate and co-lead author of the report on the research, said that in order to transmit a data signal on a small chip comprising a great number of components it's essential to have a precise control over its direction, otherwise information will be lost.

The uniqueness of the device lies in its patterning, according to the research team. It comprises a thin gold sheet with perforations resembling a skeleton of a fish.