Free Newsletters - Space News - Defense Alert - Environment Report - Energy Monitor
. Space Industry and Business News .




TECH SPACE
Pitt team first to detect exciton in metal
by Staff Writers
Pittsburgh PA (SPX) Jun 03, 2014


File image.

University of Pittsburgh researchers have become the first to detect a fundamental particle of light-matter interaction in metals, the exciton. The team will publish its work online June 1 in Nature Physics.

Mankind has used reflection of light from a metal mirror on a daily basis for millennia, but the quantum mechanical magic behind this familiar phenomenon is only now being uncovered.

Physicists describe physical phenomena in terms of interactions between fields and particles, says lead author Hrvoje Petek, Pitt's Richard King Mellon Professor in the Department of Physics and Astronomy within Kenneth P. Dietrich School of Arts and Sciences. When light (an electromagnetic field) reflects from a metal mirror, it shakes the metal's free electrons (the particles), and the consequent acceleration of electrons creates a nearly perfect replica of the incident light (the reflection).

The classical theory of electromagnetism provides a good understanding of inputs and outputs of this process, but a microscopic quantum mechanical description of how the light excites the electrons is lacking.

Petek's team of experimental and theoretical physicists and chemists from the University of Pittsburgh and Institute of Physics in Zagreb, Croatia, report on how light and matter interact at the surface of a silver crystal. They observe, for the first time, an exciton in a metal.

Excitons, particles of light-matter interaction where light photons become transiently entangled with electrons in molecules and semiconductors, are known to be fundamentally important in processes such as plant photosynthesis and optical communications that are the basis for the Internet and cable TV.

The optical and electronic properties of metals cause excitons to last no longer than approximately 100 attoseconds (0.1 quadrillionth of a second). Such short lifetimes make it difficult for scientists to study excitons in metals, but it also enables reflected light to be a nearly perfect replica of the incoming light.

Yet, Branko Gumhalter at the Institute of Physics predicted, and Petek and his team experimentally discovered, that the surface electrons of silver crystals can maintain the excitonic state more than 100 times longer than the bulk metal, enabling the excitons in metals to be experimentally captured by a newly developed multidimensional coherent spectroscopic technique.

The ability to detect excitons in metals sheds light on how light is converted to electrical and chemical energy in plants and solar cells, and in the future it may enable metals to function as active elements in optical communications. In other words, it may be possible to control how light is reflected from a metal.

The paper, "Transient Excitons at Metal Surfaces," will be published June 1 in the online edition of Nature Physics. The work was supported by a grant from the Division of Chemical Sciences, Geosciences, and Biosciences of the Office of Basic Energy Sciences of the U.S. Department of Energy.

.


Related Links
University of Pittsburgh
Space Technology News - Applications and Research






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





TECH SPACE
New Method of Wormlike Motion Lets Gels Wiggle through Water
Cincinnati OH (SPX) Jun 03, 2014
Next time you spot an earthworm sliding through fresh dirt, take a closer look. What you're seeing is an organic movement called peristaltic locomotion that has been meticulously refined by nature. Jarod Gregory, an undergraduate student in the University of Cincinnati's College of Engineering and Applied Science, used a worm's contracting and expanding motion to provide a way for gels to swim i ... read more


TECH SPACE
Russia preparing to launch Okno space surveillance system at full capacity

Citizen Scientists Contact Vintage Spacecraft

New Method of Wormlike Motion Lets Gels Wiggle through Water

Leaving the islands

TECH SPACE
NATO agency extends Globalcomms services

Rockwell supplying radios, satellite terminals to Canadian military

Exelis to help repair, modernize tactical radios

The U.S. Navy has contracted Harris Corporation for next-gen radios

TECH SPACE
SpaceX unveils capsule to ferry astronauts to space

Roscosmos Scolded for 'Pestering Society' with Proton Crash Theories

Elon Musk to present manned DragonV2 spacecraft on May 29

Russia puts satellite in orbit from sea platform after 2013 flop

TECH SPACE
Gannet sat nav reveals impact of fishing vessels

Chinese army regulates sat nav use

Beidou to help safeguard fishermen on high seas

China's domestic navigation system guides Pakistan

TECH SPACE
USAF crisis, contingency planning gets Northrop support

Heavy airplane traffic potentially a major contributor to pollution in Los Angeles

Chinese ship in latest glitch in MH370 search mission

Thales teams with Provincial Aerospace

TECH SPACE
EMCORE Introduces Internal Fiber Delay Line System for the Optiva Platform

New analysis eliminates a potential speed bump in quantum computing

NIST chip produces and detects specialized gas for biomedical analysis

Merger planned of electronic component providers

TECH SPACE
Ten year-old Dragon gains new strength

Sentinel-1 aids Balkan flood relief

Japan launches land observing satellite

Airbus partners with BAE for radar satellite imagery

TECH SPACE
New pollution rules will reduce asthma, heart attacks: Obama

Cutting Carbon Emissions Reduces Everyday Air Pollution

Sweden to sue EU for delay on hormone disrupting chemicals

Dangerous nitrogen pollution could be halved




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.