A step toward optical transistors? Study demonstrates new way to control light in semiconductor nanocrystals

Apr 09, 2013

(Phys.org) —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 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.

Explore further: A crystal wedding in the nanocosmos

More information: pubs.acs.org/doi/abs/10.1021/nl3044053

Related Stories

'Squeezing' light into quantum dots

Apr 01, 2009

(PhysOrg.com) -- “Quantum wells have been instrumental in telecommunications, enabling light amplification,” Patanjali Kambhampati tells PhysOrg.com, “but theory has suggested that a very small - colloidal - quantu ...

Physicists lay the groundwork for cooler, faster computing

Dec 14, 2009

University of Toronto quantum optics researchers Sajeev John and Xun Ma have discovered new behaviours of light within photonic crystals that could lead to faster optical information processing and compact computers that ...

Recommended for you

A crystal wedding in the nanocosmos

Jul 23, 2014

Researchers at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), the Vienna University of Technology and the Maria Curie-Skłodowska University Lublin have succeeded in embedding nearly perfect semiconductor ...

PPPL studies plasma's role in synthesizing nanoparticles

Jul 22, 2014

DOE's Princeton Plasma Physics Laboratory (PPPL) has received some $4.3 million of DOE Office of Science funding, over three years, to develop an increased understanding of the role of plasma in the synthesis ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

EyeNStein
1 / 5 (3) Apr 09, 2013
Sounds good. Hard to agree/disagree with such vague details.