Nanostructures can open up new possibilities for optical memory and electronic switches. This week, potential applications for nanoantennae were shown in a new paper published in the journal Light, Science, and Applications by researchers from the University of Southampton in the United Kingdom.
Their fast nanoscale optical transistor uses a gold nanoantenna to achieve low-energy optical switching.
“If we are able to actively tune a nanoantenna using an electrical or optical signal, we could achieve transistor-type switches for light with nanometer-scale footprint for datacommunication,” said lead researcher Professor Otto Muskens. “Such active devices could also be used to tune the antenna’s light-concentration effects, leading to new applications in switchable and tuneable antenna-assisted processes.”
Optical nanostructures are an important part of an emerging market, with new applications such as small optical circuits. They concentrate light to a degree far below what is possible with conventional optics, which can be used to increase the effects of light in localized energy conversion, new frequencies of light generated through nonlinear optics, and other applications.
In Southampton’s case, the researchers used vanadium dioxide to achieve low-energy optical switching with a phase-change material. The vanadium dioxide is capable of changing its properties from an insulator to a metal through the application of higher temperatures. Gold nanoantennae were then fabricated on top of the vanadium dioxide film.
“The nanoantenna assists the phase transition of the vanadium dioxide by locally concentrating energy near the tips of the antenna,” said Muskens. “These positions are also where the antenna resonances are the most sensitive to local perturbations. Antenna-assisted switching thus results a large effect while requiring only a small amount of energy.”
Filed Under: Materials • advanced