Scientists discover new method of observing interactions in nanoscale systems

January 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: Flexible design approach for nanosensors that overcomes practicality and reliability issues now available

Related Stories

Recommended for you

Physicists develop new technique to fathom 'smart' materials

November 26, 2015

Physicists from the FOM Foundation and Leiden University have found a way to better understand the properties of manmade 'smart' materials. Their method reveals how stacked layers in such a material work together to bring ...

Mathematicians identify limits to heat flow at the nanoscale

November 24, 2015

How much heat can two bodies exchange without touching? For over a century, scientists have been able to answer this question for virtually any pair of objects in the macroscopic world, from the rate at which a campfire can ...

New sensor sends electronic signal when estrogen is detected

November 24, 2015

Estrogen is a tiny molecule, but it can have big effects on humans and other animals. Estrogen is one of the main hormones that regulates the female reproductive system - it can be monitored to track human fertility and is ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

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.