Plasmon transporting thin films herald nanoscale light control

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Purdue University researchers have transported plasmons, tiny electron excitations coupled to light, using a thin film of titanium nitride, which could one day enable a device capable of directing and manipulating optical signals on the nanoscale.

Such a capability is expected to bring about optoelectronic devices with unprecedented speed and efficiency. Titanium nitride, a ceramic, is the latest addition to a list of plasmon supporting materials that have previously only included metals. Metals carry electricity with ease but normally do nothing to transmit light waves. Widening the range of materials able to transport plasmons makes it more likely a viable device can be created.

‘Plasmonics is an important technology for nanoscale optical circuits, sensing, and data storage because it can focus light down to nanoscale,’ said Purdue researcher Alexandra Boltasseva. ‘Unlike gold and silver, titanium nitride is compatible with standard semiconductor manufacturing technology.’

The researchers are now looking into a manufacturing method known as molecular beam epitaxy that would enable them to grow the light transmitting films and layered structures known as superlattices crystal-by-crystal.