Nano ‘terminator style’ antennae

12 October 2017:

The liquid metal, shape-shifting T-1000 Terminator cyborg, featuring in a 1991 science-fiction film Terminator 2, was made possible due to breakthroughs in computer-generated imagery.

Some 25 years later, using breakthroughs in physics and chemistry CNBP scientists Dr Ivan Maksymov and Prof Andy Greentree at RMIT University have shown reconfigurable liquid-metal optical nanoantennae.

“An optical nanoantenna operates similarly to a conventional radio-frequency antenna, but its size is millions of times smaller” explains Dr Ivan Maksymov, “so it can receive and emit light similar to how a mobile phone antenna receives and emits radio waves.”

“The shape and length of the metal components that form a radio-frequency antenna determine its major properties such as operating frequency and radiation pattern,” explains Prof Andy Greentree, “so a liquid metal that can change its shape by applying voltage allows for changing antenna properties, which otherwise is difficult to achieve with fixed metal parts.”

“However, reconfigurability of optical nanoantennae is even more difficult to achieve than in radio-frequency antennae, because of their small size and lack of technologies enabling us to apply voltage to nanoscale sized objects. Therefore, we proposed a new solution – reconfiguration of liquid-metal nanoparticles using ultrasound.”

Continued Dr Maksymov, “A liquid-metal nanoparticle can change its shape due to capillary oscillations, which can be seen by everybody when observing water drops falling from a leaking kitchen tap. Drops change their shape when they detach from the tap and fall into the sink. In our work, we use ultrasound to change the shape of liquid-metal nanodroplets, which changes the nanoantenna’s operating frequency.”

“But fundamental physics remains the same as in the case of water drops.”

The paper ‘Dynamically reconfigurable plasmon resonances enabled by capillary oscillations of liquid-metal nanodroplets’ is accessible online.