Search Menu
Photonics Media Photonics Buyers' Guide Photonics EDU Photonics Spectra BioPhotonics EuroPhotonics Industrial Photonics Photonics Showcase Photonics ProdSpec Photonics Handbook
More News
Email Facebook Twitter Google+ LinkedIn Comments

Excitons Form Luminescent Rings

Photonics Spectra
Oct 2002
Two independent teams have reported observing photoluminescent rings from indirect excitons in coupled quantum wells. Excitons are boson particles similar to a hydrogen atom, except with a charge hole instead of a proton. Indirect excitons are created when the electron and hole pair divides between two coupled wells. This separation leads to a longer lifetime for the particle -- up to 100 ns.

The groups created the excitons by directing an approximately 630-nm laser beam into the well structures. The particles spread out from this spot in a dark state and then began to luminesce up to hundreds of microns away, creating a visible ring around the laser spot.

It is not known how or why the excitons migrate or luminesce in such a way, although both teams report that excitation density has a direct effect upon the distance that the ring forms from the laser spot.

A team from the Lawrence Berkeley National Laboratory in California, the Russian Academy of Sciences in Chernogolovka and the University of California at Santa Barbara and at Berkeley, demonstrated this phenomenon in GaAs/AlGaAs quantum wells. Scientists from the University of Pittsburgh and from Bell Labs in Murray Hill, N.J., used InGaAs quantum wells. Both groups reported their results in the Aug. 15 issue of Nature.

Research & Technology

Terms & Conditions Privacy Policy About Us Contact Us
back to top
Facebook Twitter Instagram LinkedIn YouTube RSS
©2018 Photonics Media, 100 West St., Pittsfield, MA, 01201 USA,

Photonics Media, Laurin Publishing
x Subscribe to Photonics Spectra magazine - FREE!
We use cookies to improve user experience and analyze our website traffic as stated in our Privacy Policy. By using this website, you agree to the use of cookies unless you have disabled them.