Penn Theorists to Create Optical Circuit Elements

Sep 27, 2005

Engineers at the University of Pennsylvania have theorized a means of shrinking electronics so they could be run using light instead of electricity. In the search to create faster, smaller and more energy-efficient electronics, researchers have looked elsewhere in the electromagnetic spectrum, which ranges from the low-frequency energy used in everyday electronics to the high-frequency energy of gamma rays, to pass the limits of conventional technology.

In the Aug. 26 issue of Physical Review Letters, currently online, the Penn theorists outline how familiar circuit elements -- inductors, capacitors and resistors could be created on the nanoscale (about a billionth of a meter) in order to operate using infrared or visible light. The Penn researchers describe how nanoscale particles of certain materials, depending on their unique optical properties, could work as circuit elements. For example, nanoscale particles of certain metals, such as gold or silver, could perform the same function in manipulating an "electric" current as an inductor does on a circuit board.

Optical electronics would make it possible to create faster computer processors, construct nanoscale antennas or build more information-dense data- storage devices. Optical electronics could also have exotic applications that simply are not possible with conventional electronics, such as the ability to couple an electronic signal to an individual molecule or the creation of biological circuits.

"The wavelength of light can be measured in hundreds of nanometers and the technology is now available to create structures that would operate on the same or smaller scale as the wavelength of light," wrote Nader Engheta, lead author, and H. Nedwill Ramsey, professor in the Department of Electrical and Systems Engineering of Penn's School of Engineering and Applied Science. "Our work is theoretical, of course, but we do not foresee any sizable barriers to our plan to make these circuit elements in the near future."

Before they could describe how to create optical circuit elements, Engheta, his coauthors and students Alessandro Salandrino and Andrea Al had to first envision how nanoscale materials might interact with light. To do so they looked at a property critical to basic wave interaction called permittivity, which describes how a particular substance affects electromagnetic fields. If a small sphere is created, about a few tens of nanometers across, they explained, light would affect it differently based on its permittivity.

According to their models, the theorists demonstrated that nano-sized sphere made up of a nonmetallic material such as glass with permittivity greater than zero would act like a miniaturized capacitor. A nano-sized sphere made up of a metallic material such as gold or silver with a permittivity less than zero would act like a miniaturized inductor. Either material could also function like a miniaturized resistor, depending on how the optical energy is lost in it.

"So now we have three basic elements of a circuit," Enghata said. "Stacked one upon the other, you could create fairly advanced combinations of circuitry. It is even possible to use these elements to create 'nano' transmission lines and 'nano' cables.

"For years, conventional circuit elements have been the basic building bloc in making functional circuits at lower frequencies," Engheta said. "But now we have the tools to push back the limits of speed and power on electronics. This technology could have innumerable applications for consumer products, advanced instrumentation and even medicine."

Source: University of Pennsylvania

Explore further: New insights found in black hole collisions

add to favorites email to friend print save as pdf

Related Stories

Aerogel catalyst shows promise for fuel cells

Mar 02, 2015

(Phys.org)—Graphene nanoribbons formed into a three-dimensional aerogel and enhanced with boron and nitrogen are excellent catalysts for fuel cells, even in comparison to platinum, according to Rice University ...

Recommended for you

New insights found in black hole collisions

Mar 27, 2015

New research provides revelations about the most energetic event in the universe—the merging of two spinning, orbiting black holes into a much larger black hole.

X-rays probe LHC for cause of short circuit

Mar 27, 2015

The LHC has now transitioned from powering tests to the machine checkout phase. This phase involves the full-scale tests of all systems in preparation for beam. Early last Saturday morning, during the ramp-down, ...

Swimming algae offer insights into living fluid dynamics

Mar 27, 2015

None of us would be alive if sperm cells didn't know how to swim, or if the cilia in our lungs couldn't prevent fluid buildup. But we know very little about the dynamics of so-called "living fluids," those ...

First glimpse inside a macroscopic quantum state

Mar 27, 2015

In a recent study published in Physical Review Letters, the research group led by ICREA Prof at ICFO Morgan Mitchell has detected, for the first time, entanglement among individual photon pairs in a beam ...

User comments : 0

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.