A nanoscale wireless communication system via plasmonic antennas

August 25, 2016

Chestnut Hill, Mass. (8/25/2016) - The pursuit of next-generation technologies places a premium on producing increased speed and efficiency with components built at scales small enough to function on a computer chip.

One of the barriers to advances in "on-chip" communications is the size of the electromagnetic waves at radio and microwave frequencies, which form the backbone of modern wireless technology. The relatively large waves handcuff further miniaturization.

Scientists trying to surpass these limitations are exploring the potential of optical conveyance that exploits the properties of much smaller wavelengths, such as those in the terahertz, infrared and visible frequencies.

A team of researchers at Boston College has developed the first nanoscale wireless communication system that operates at visible wavelengths using antennas that send and receive surface plasmons with an unprecedented degree of control, the team reports in the latest edition of the journal Nature's Scientific Reports.

Furthermore, the device affords an "in-plane" configuration, a prized class of two-way information transmission and recovery in a single path, according to the study, conducted by a team in the lab of Evelyn J. and Robert A. Ferris Professor of Physics Michael J. Naughton.

The findings mark an important first step toward a nanoscale version - and visible frequency equivalent - of existing wireless communication systems, according to the researchers. Such on-chip systems could be used for high-speed communication, high efficiency plasmonic waveguiding and in-plane circuit switching - a process that is currently used in liquid crystal displays.

The device achieved communication across several wavelengths in tests using near-field scanning optical microscopy, according to lead co-author Juan M. Merlo, a post-doctoral researcher who initiated the project.

"Juan was able to push it beyond the near field - at least to four times the width of a wavelength. That is true far-field transmission and nearly every device we use on a daily basis - from our cell phones to our cars - relies on far-field transmission," said Naughton.

The device could speed the transmission of information by as much as 60 percent compared to earlier plasmonic waveguiding techniques and up to 50 percent faster than plasmonic nanowire waveguides, the team reports.

Surface plasmons are the oscillations of electrons coupled to the interface of an electromagnetic field and a metal. Among their unique abilities, surface plasmons can confine energy on that interface by fitting into spaces smaller than the waves themselves.

Researchers trying to exploit these subwavelength capabilities of surface plasmons have developed metallic structures, including plasmonic antennas. But a persistent problem has been the inability to achieve "in-line" containment of the emission and collection of the electromagnetic radiation.

The BC team developed a device with a three-step conversion process that changes a surface plasmon to a photon on transmission and then converts that elemental electromagnetic particle back to a surface plasmon as the receiver picks it up.

"We have developed a device where plasmonic antennas communicate with each other with photons transmitting between them," said Naughton. "This is done with high efficiency, with energy loss reduced by 50 percent between one antenna and the next, which is a significant enhancement over comparable architectures."

Central to the newfound control of the surface plasmons was the creation of a small gap of air between the waves and the silver surface of the device, said Merlo, who earned his PhD at Mexico's National Institute of Astrophysics, Optics and Electronics. By removing a portion of the glass substrate, the team reduced the disruptive pull of the material on the photons in transmission. Expanding and narrowing that gap proved crucial to tuning the device.

With traditional silicon waveguides, dispersion reduces information transmission speed. Without that impediment, the new device capitalizes on the capability of surface plasmons to travel at 90 to 95 percent of the speed of light on a silver surface and photons traveling between the antennas at their inherent speed of light, Merlo said.

"Silicon-based optical technology has been around for years," said Merlo. "What we are doing is improving it to make it faster. We're developing a tool to make silicon photonics faster and greatly enhance rates of communication."
-end-
In addition to Naughton and Merlo, the paper was co-authored by Professor Krzysztof Kempa, Senior Research Associate Michael J. Burns, and graduate students Nathan T. Nesbitt, Yitzi M. Calm, Aaron H. Rose, Luke D'Imperio, Chaobin Yang and Jeffrey R. Naughton.

The full report can be found at: http://www.nature.com/articles/srep31710

Boston College

Related Cell Phones Articles from Brightsurf:

Smart phones are empowering women worldwide
By giving women access to information they otherwise wouldn't have, mobile phones are transforming lives.

National survey shows different bacteria on cell phones and shoes
The largest study of its kind in the US shows thousands of different types of bacteria living on cell phones and shoes, including groups that have barely been studied by scientists.

New lithium batteries from used cell phones
Research from the University of Cordoba (Spain) and San Luis University (Argentina) was able to reuse graphite from cell phones to manufacture environmentally friendly batteries.

Thyroid cancer, genetic variations, cell phones linked in YSPH study
Radiation from cell phones is associated with higher rates of thyroid cancer among people with genetic variations in specific genes, a new study led by the Yale School of Public Health finds.

Dissemination of pathogenic bacteria by university student's cell phones
New research has demonstrated the presence of S. aureus in 40% of the cell phones of students sampled at a university.

'Technoference': We're more tired & less productive because of our phones
An Australian survey of 709 mobile phone users (aged 18 to 83), led by Queensland University of Technology, has found one in five women and one in eight men are losing sleep due to bad phone habits.

Research could lead to more durable cell phones and power lines
Researchers from Binghamton University, State University of New York have developed a way to make cell phones and power lines more durable. 

Cell phones without annual plans offer limited help to homeless people
The vast majority of older homeless adults have access to mobile phones, but they are usually basic phones, without annual contracts that let them keep stable numbers, and thus are only practical for one-way communication, according to a UC San Francisco study of how homeless people use mobile and Internet technology.

Laws designed to ban or curb drivers' use of cell phones are saving motorcyclists' lives
Laws to ban or curb drivers' use of cell phones and other handheld devices have greatly reduced the rate of fatalities for motorcyclists, according to a new study from Florida Atlantic University and the University of Miami.

Toxic chemicals calling: Cell phones as a source of flame retardants
New research by environmental scientists at the University of Toronto suggests that the exterior of mobile phones could be a source of toxic chemicals, or at least an aggregate indicator of the chemicals to which people are exposed on a daily basis.

Read More: Cell Phones News and Cell Phones Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.