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Nanoscale Laser Researchers Peek Into 'Uncertainty'

by Editor1 last modified January 27, 2008 - 15:21

A group of international researchers led by a team from Ohio University is exploring new frontiers in quantum optics, and in the process may have peeked through Heisenberg’s uncertainty principle.

Nanoscale Laser Researchers Peek Into 'Uncertainty'

Sasha Govorov, an Ohio University theoretical physicist, proposes new nonlinear theory

Using high-powered laser spectroscopy and quantum dots, the group 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 for the first time, which resulted in a new nonlinear theory.

“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,” Sasha Govorov, an Ohio University theoretical physicist said of the work. The work was recently published recently in Nature.

One focus of the work was the study of 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.

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

But in a new high-resolution laser spectroscopy experiment at the University of Munich’s Center of NanoScience (led by M. Kroner and K. Karrai) scientists 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.

The research was funded by the National Science Foundation (USA), and a group of European research agencies in Germany, the U.K, and Ohio University’s Nanobiotechnology Initiative.

Other co-authors on the study were S. Remi, B. Biedermann, S. Seidl and of the Ludwig-Maximilians University, W. Zhang of Ohio University; A. Badolato and P.M. Petroff of the University of California at Santa Barbara; and R. Barbour, B.D. Gerardot and R.J. Warburton of the Heriot-Watt University in Edinburgh, Scotland.