Scientists discover new method of observing interactions in nanoscale systems

Jan 16, 2008

Scientists have used new optical technologies to observe interactions in nanoscale systems that Heisenberg’s uncertainty principle usually would prohibit, according to a study published Jan. 17 in the journal Nature.

Researchers conducted experiments with high-powered lasers and quantum dots —artificial atoms that could be the building blocks of nanoscale devices for quantum communication and computing — to learn more about physics at the nanoscale.

One common phenomenon in physics is the Fano effect, which occurs when a discrete quantum state – an atom or a molecule – interacts with a continuum state of the vacuum or the host material surrounding it. The Fano effect changes the way an atom or molecule absorbs light or radiation, said Sasha Govorov, an Ohio University theoretical physicist who is co-author on the paper.

In experiments on nanoscale systems, Heisenberg’s uncertainty principle sometimes blocks scientists from observing the Fano effect, Govorov explained. The interaction of the nanoscale system and its continuum state surroundings can’t be detected.

But in a new high-resolution laser spectroscopy experiment led by M. Kroner and K. Karrai of the Center of NanoScience at the Ludwig-Maximilians University in Munich, Germany, scientists utilized a new method. They measured photons scattered from a single quantum dot while increasing the laser intensity to saturate the dot’s optical absorption. This allowed them to observe very weak interactions, signaled by the appearance of the Fano effect, for the first time.

A theory for the new nonlinear method was developed by Govorov. “Our theory suggests that the nonlinear Fano effect and the method associated with it can be potentially applied to a variety of physical systems to reveal weak interactions,” he said.

Scientists also can revisit older experiments on atoms by using modern tools such as highly coherent light sources that are strong enough to reveal such nonlinear Fano-effects, Karrai said. “We can explore new frontiers in quantum optics,” he noted.

Source: Ohio University

Explore further: 3-D images of tiny objects down to 25 nanometres

Related Stories

Recommended for you

3-D images of tiny objects down to 25 nanometres

22 hours ago

Scientists at the Paul Scherrer Institute and ETH Zurich (Switzerland) have created 3D images of tiny objects showing details down to 25 nanometres. In addition to the shape, the scientists determined how ...

Solving molybdenum disulfide's 'thin' problem

Mar 27, 2015

The promising new material molybdenum disulfide (MoS2) has an inherent issue that's steeped in irony. The material's greatest asset—its monolayer thickness—is also its biggest challenge.

Snowflakes become square with a little help from graphene

Mar 25, 2015

The breakthrough findings, reported in the journal Nature, allow better understanding of the counterintuitive behaviour of water at the molecular scale and are important for development of more efficient techno ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

NeilFarbstein
not rated yet Jan 16, 2008
The casimir effect arises from interactions between the vacuum and 2 plates placed very closely to each other.

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.