A Step Toward Optical Transistors?
McGill researchers demonstrate new way to control light in semiconductor nanocrystals
As demand for computing and communication capacity surges, the global communication infrastructure struggles to keep pace, since the light signals transmitted through fiber-optic lines must still be processed electronically, creating a bottleneck in telecommunications networks.
While the idea of developing an optical transistor to get around this problem is alluring to scientists and engineers, it has also remained an elusive vision, despite years of experiments with various approaches. Now, McGill University researchers have taken a significant, early step toward this goal by showing a new way to control light in the semiconductor nanocrystals known as “quantum dots.”
In results published online recently in the journal Nano Letters, PhD candidate Jonathan Saari, Prof. Patanjali (Pat) Kambhampati and colleagues in McGill’s Department of Chemistry show that all-optical modulation and basic Boolean logic functionality – key steps in the processing and generation of signals – can be achieved by using laser-pulse inputs to manipulate the quantum mechanical state of a semiconductor nanocrystal.
“Our findings show that these nanocrystals can form a completely new platform for optical logic,” says Saari. “We’re still at the nascent stages, but this could mark a significant step toward optical transistors.”
Quantum dots already are used in applications ranging from photovoltaics, to light-emitting diodes and lasers, to biological imaging. The Kambhampati group’s latest findings point toward an important new area of potential impact, based on the ability of these nanocrystals to modulate light in an optical gating scheme.
“These results demonstrate the proof of the concept,” Kambhampati says. “Now we are working to extend these results to integrated devices, and to generate more complex gates in hopes of making a true optical transistor.”
The findings build on a 2009 paper by Kambhampati’s research group in Physical Review Letters. That work revealed previously unobserved light-amplification properties unique to quantum dots, which are nanometer-sized spheroids with size-dependent optical properties, such as absorption and photoluminescence.
The research for the Nano Letters article was supported by the Canada Foundation for Innovation, the Natural Sciences and Engineering Research Council of Canada, and the Fonds de recherche du Québec - Nature et technologies.
To view the article: http://pubs.acs.org/doi/abs/10.1021/nl3044053
Chris Chipello | Newswise
The most recent press releases about innovation >>>
Die letzten 5 Focus-News des innovations-reports im Überblick:
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Rice University researchers test 3-D carbon nanostructures' thermal transport abilities
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...