Imec and Ghent University have demonstrated interaction between light and sound in a nanoscale waveguide which allows photons to control photons and may pave the way to production of silicon photonic ICs.
Silicon photonic nanowires carrying optical signals work because light moves slower in the silicon core than in the surrounding air and glass. The light is trapped inside the wire by the phenomenon of total internal reflection.
Confining light is one thing, but manipulating it is another. The issue is that one light beam cannot easily change the properties of another, but light-matter interaction allows some photons to control other photons.
The Imec/Ghent researchers managed to confine not only light but also sound to the silicon nanowires.
The sound oscillates ten billion times per second. The researchers realised that the sound cannot be trapped in the wire by total internal reflection. Unlike light, sound moves faster in the silicon core than in the surrounding air and glass.
So the scientists made the core capable of ensuring that any vibrational wave trying to escape it would bounce back. Doing so, they confined both light and sound to the same nanoscale waveguide core – a world’s first observation.
Trapped in the nanowire, the light and vibrations strongly influence each other: light generates sound and sound shifts the color of light, a process known as stimulated Brillouin scattering.
The scientists exploited this interaction to amplify specific colors of light. They anticipate this demonstration to open up new ways to manipulate optical information. For instance, light pulses could be converted into sonic pulses and back into light – thereby implementing much-needed delay lines.
Further, the researchers expect that similar techniques can be applied to even smaller entities such as viruses and DNA. These particles have unique acoustic vibrations that may be used to probe their global structure.
from News http://ift.tt/1A4ZyDJ
via Yuichun
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