Making a caged ion blink

By Eric Smalley, Technology Research News

Researchers at Oak Ridge National Laboratory and Nanocrystals Technology have discovered that if you trap a europium ion in a nanocrystal cage and fire a laser at it, the ion will emit red light.

Not only can the ion be made to blink, it will do so at four distinct levels of brightness. Europium is a rare earth metal widely used for its light-emitting properties.

Blinking ions could be used for optical storage devices and displays. An optical storage device based on the technology would be particularly dense because the four levels of brightness would allow each ion to serve as a four-bit element.

Firing a laser at a caged europium ion changes the symmetry of the nanocrystal cage, said Adosh Mehta, a postdoctoral researcher at Oak Ridge National Laboratory. When the crystal symmetry changes, otherwise forbidden transitions between energy states in the europium ion occur, producing red light, he said.

The blinking process could be applied to practical technology within five years, said Mehta. A paper on the process written by R. N. Bhargava, V. Chhabra, and B. Kulkarni was published in the July 6 issue of the Journal of Physical Chemistry B. The research was funded by the Department of Energy.

Timeline:  <5 years
Funding:   Government
TRN Categories:   Nanotechnology; Semiconductors and Materials
Story Type:   News
Related Elements:   Photo; Technical paper "On-Off Blinking and Multiple Bright States of Single Europium Ions in Eu3+:Y2O3 Nanocrystals" in July 6 Journal of Physical Chemistry B


July 26, 2000

Page One

Tiny robots flex their muscles

Optical coax takes take turns

Making a caged ion blink

Simulation acts 7-year-old's age

Computer science faces decision theory


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