Hybrid nanoantenna designed to manipulate visible light

November 16, 2018, Agency for Science, Technology and Research (A*STAR), Singapore
Hybrid nanoantenna designed to manipulate visible light
The nanoantenna designed by Ho and co-workers is modeled on the classic roof-top antenna design, but the tiny gold bow-tie shape and silicon dipoles allow it to transmit visible light instead of radio waves. Credit: A*STAR Institute of Materials Research and Engineering

A nanoscale optical antenna developed by researchers at A*STAR allows the manipulation of visible light waves on the scale of microchips. Such nanoantennae may enable the development of high-resolution imaging systems in small mobile devices.

Photons in can carry more information than electrons traveling through . If light could be directed within nanoscale chips as a means of wireless data transfer, it could open the way for technologies such as high-speed imaging for medical uses, and phone screens that boast high resolution, three-dimensional displays.

Now, Jinfa Ho, Joel Yang, and Arseniy Kuznetsov and their team at A*STAR's Institute of Materials Research and Engineering have developed a nanoscale that can transmit at the chip scale. Crucially, their design is the first to enable precise control of the direction that the light waves are traveling, while limiting radiation leakage that could create interfering crosstalk between components.

Most people would recognize pronged radio antennae from building roofs, comprising an active feed element and a series of parallel metal rods, or 'dipole directors'. This , called a Yagi-Uda antenna, is a highly successful method of transmitting radio waves; the size of each dipole is designed to respond to radio waves of specific wavelengths and direct them as needed.

"For Yagi-Uda antennas to operate in the optical wavelength regime, they must be scaled down to nanometer sizes," says Ho. "Most previous attempts retained the use of metals, which have significantly losses at optical frequencies because of absorption into the metal. Instead we used a gold source dipole configured into a bow-tie shape, coupled with silicon directors (see image above)." It is the use of both plasmonic (gold bow tie) and dielectric (silicon director) structures that leads to the nanoantenna's hybrid nature.

The electric field hotspot created in the middle of the bow-tie when the antenna was in use greatly enhanced the gold's photoluminescent properties. This allowed the researchers to image the tiny antenna and manipulate the direction of the light signal. Using silicon directors meant that high dipole strengths were maintained throughout the antenna, with low dissipation losses.

"By exciting several dipoles in close proximity to each other with the correct phase difference, we enhanced radiation in the desired direction thanks to destructive and constructive interference," explains Ho. "This improved directivity compared with previous designs."

The team's next step is to create a nanoantenna that will change emission under different electrical signals. "Imagine nanoantennae arrays emitting in different directions, creating high-resolution images visible from multiple viewpoints," adds Yang.

Explore further: Targeted creation and control of photons: thanks to a new design for optical antennas

More information: Jinfa Ho et al. Highly Directive Hybrid Metal–Dielectric Yagi-Uda Nanoantennas, ACS Nano (2018). DOI: 10.1021/acsnano.8b04361

Related Stories

Updating high-resolution MRI

October 31, 2018

How can you make a high-frequency MRI machine more precise? By taking an electrical engineering approach to creating a better, uniform magnetic field.

Silicon nanoparticles trained to juggle light

August 24, 2016

A team of physicists from ITMO University (Saint Petersburg) and Moscow Institute of Physics and Technology (MIPT) has demonstrated the potential of silicon nanoparticles for effective non-linear light manipulation. Their ...

Bio-inspired nanoantennas for light emission

July 30, 2012

Just as radio antennas amplify the signals of our mobile phones and televisions, the same principle can apply to light. For the first time, researchers from CNRS and Aix Marseille Université have succeeded in producing ...

Recommended for you

Meteorite source in asteroid belt not a single debris field

February 17, 2019

A new study published online in Meteoritics and Planetary Science finds that our most common meteorites, those known as L chondrites, come from at least two different debris fields in the asteroid belt. The belt contains ...

Diagnosing 'art acne' in Georgia O'Keeffe's paintings

February 17, 2019

Even Georgia O'Keeffe noticed the pin-sized blisters bubbling on the surface of her paintings. For decades, conservationists and scholars assumed these tiny protrusions were grains of sand, kicked up from the New Mexico desert ...

Archaeologists discover Incan tomb in Peru

February 16, 2019

Peruvian archaeologists discovered an Incan tomb in the north of the country where an elite member of the pre-Columbian empire was buried, one of the investigators announced Friday.

Where is the universe hiding its missing mass?

February 15, 2019

Astronomers have spent decades looking for something that sounds like it would be hard to miss: about a third of the "normal" matter in the Universe. New results from NASA's Chandra X-ray Observatory may have helped them ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.