Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > 'Cornell dots' make the world's tiniest laser

Schematic (not to scale) of the modified Cornell dot used to create the world's smallest laser. The particle, 44 nanometers in diameter, consists of a silica shell surrounding a 14-nanometer gold core. Energy bouncing between dye molecules and a plasmon oscillation in electrons in the gold amplifies the light output.

Provided/Wiesner Lab, Cornell University
Schematic (not to scale) of the modified Cornell dot used to create the world's smallest laser. The particle, 44 nanometers in diameter, consists of a silica shell surrounding a 14-nanometer gold core. Energy bouncing between dye molecules and a plasmon oscillation in electrons in the gold amplifies the light output. Provided/Wiesner Lab, Cornell University

Abstract:
Researchers have modified nanoparticles known as "Cornell dots" to make the world's tiniest laser -- so small it could be incorporated into microchips to serve as a light source for photonic circuits. The device may also have applications for sensors, solar collectors and in biomedicine.

'Cornell dots' make the world's tiniest laser

Ithaca, NY | Posted on August 18th, 2009

The original Cornell dots, created by Ulrich Wiesner, the Spencer T. Olin Professor of Engineering at Cornell, consist of a core of dye molecules enclosed in a silica shell to create an unusually luminous particle. The new work by researchers at Norfolk (Virginia) State University (NSU), Purdue University and Cornell uses what Wiesner calls "hybrid Cornell dots," which have a gold core surrounded by a silica shell in which dye molecules are embedded.

The research is reported in the Aug. 16 online issue of the journal Nature and will appear in a coming print issue.

Using nanoparticles 44 nanometers (nm -- one billionth of a meter or about three atoms in a row) wide, the device is the smallest nanolaser reported to date, and the first operating in visible light wavelengths, the researchers said.

"This opens an interesting playground in terms of miniaturization," said Wiesner. "For the first time we have a building block a factor of 10 smaller than the wavelength of light."

An optical laser this small is impossible because a laser develops its power by bouncing light back and forth in a tuned cavity whose length must be at least half the wavelength of the light to be emitted. In the first tests of the new device, the light emitted had a wavelength of 531 nm, in the green portion of the visible spectrum.

In a conventional laser, molecules are excited by an outside source of energy, which may be light, electricity or a chemical reaction. Some molecules spontaneously release their energy as photons of light, which bounce back and forth between two reflectors, in turn triggering more molecules to emit photons.

In the new device, dye molecules in the nanoparticle are excited by a pumping laser. A few molecules spontaneously release their added energy to generate a plasmon -- a wave motion of free electrons at an optical frequency -- in the gold core. In the tiny space, the dye molecules and the gold core are coupled by electric fields, explains Purdue co-author Vladimir Shalaev.

Oscillations of the plasmon in turn trigger more dye molecules to release their energy, which further pumps up the plasmon, creating a "spaser" (surface plasmon amplification by stimulated emission of radiation). When the energy of the system reaches a threshold the electric field collapses, releasing its energy as a photon. The size of the core -- 14 nm in diameter -- is chosen to set up a resonance that reinforces a wave corresponding to the desired 531 nm light output.

Tests at NSU indicate that the lasing effect occurs within each Cornell dot and is not a phenomenon of a collection of the nanoparticles working together, making this unquestionably the world's smallest laser.

"Some people argue that the ability to produce a surface plasmon in this way will be even more useful," added NSU professor and lead author Mikhail Noginov. It has been suggested that plasmons could be used to send signals across a microchip at the speed of light -- much faster than electrons in wires -- but in less space than photonic circuits need.

The idea of a spaser was first proposed in 2003 by physicists Mark Stockman at Georgia State University and David Bergman at Tel Aviv University. The theory behind the new approach was developed by Evgenii Narimanov at Purdue.

The work is funded by the National Science Foundation, with additional funding from the U.S. Army Research Office.

####

About Cornell University
Cornell University is a private university located in Ithaca, New York, USA, that is a member of the Ivy League.

With consistent top 15 rankings, Cornell is largely considered one of the preeminent Universities in the world. Cornell counts more than 255,000 living alumni, 28 Rhodes Scholars and 40 Nobel laureates affiliated with the university as faculty or students. The student body consists of over 13,000 undergraduate and 6,000 graduate students from all fifty states and one hundred and twenty-two countries. Cornell produces more graduates that go on to become doctors than any other university in the USA. It also produces the largest number of graduates in the life sciences who continue for Ph.D. degrees, and is ranked fourth in the world in producing the largest number of graduates who go on to pursue Ph.D.s at American institutions. Research is a central element of the university's mission; in 2006 Cornell spent $649 million on research and development. In 2007, Cornell ranked fifth among universities in the U.S. in fund-raising, collecting $406.2 million in private support.

From Wikipedia, the free encyclopedia

For more information, please click here

Contacts:
Media Contact:
Blaine Friedlander
(607) 254-8093


Cornell Chronicle:
Bill Steele
(607) 255-7164

Copyright © Cornell University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

GS7 Graphene Sensor maybe Solution in Fight Against Cancer January 25th, 2015

Toyocolor to Launch New Carbon Nanotube Materials at nano tech 2015 January 24th, 2015

NANOPOSTER 2015 - 5th Virtual Nanotechnology Conference - call for abstracts January 24th, 2015

Nanosensor Used for Simultaneous Determination of Effective Tea Components January 24th, 2015

Possible Futures

GS7 Graphene Sensor maybe Solution in Fight Against Cancer January 25th, 2015

Nanotechnology in Energy Applications Market Research Report 2014-2018: Radiant Insights, Inc January 15th, 2015

'Mind the gap' between atomically thin materials December 23rd, 2014

A novel method for identifying the body’s ‘noisiest’ networks November 19th, 2014

Nanomedicine

Teijin to Participate in Nano Tech 2015 January 22nd, 2015

2nd International Conference on Infectious Diseases & Nanomedicine (December 15-18, 2015, Kathmandu, NEPAL) January 22nd, 2015

Anti-microbial coatings with a long-term effect for surfaces – presentation at nano tech 2015 in Japan January 21st, 2015

A spoonful of sugar in silver nanoparticles to regulate their toxicity January 21st, 2015

Sensors

GS7 Graphene Sensor maybe Solution in Fight Against Cancer January 25th, 2015

Nanosensor Used for Simultaneous Determination of Effective Tea Components January 24th, 2015

Iranian Scientists Produce Graphene-Based Oxygen Sensor January 23rd, 2015

Graphene brings quantum effects to electronic circuits January 22nd, 2015

Announcements

GS7 Graphene Sensor maybe Solution in Fight Against Cancer January 25th, 2015

Toyocolor to Launch New Carbon Nanotube Materials at nano tech 2015 January 24th, 2015

NANOPOSTER 2015 - 5th Virtual Nanotechnology Conference - call for abstracts January 24th, 2015

Nanosensor Used for Simultaneous Determination of Effective Tea Components January 24th, 2015

Quantum Dots/Rods

Rice-sized laser, powered one electron at a time, bodes well for quantum computing January 15th, 2015

Shining a light on quantum dots measurement January 15th, 2015

Carbon Nanotubes Increase Efficiency of Solar Cells January 12th, 2015

TCL 55” Quantum Dot TV with Color IQ™ Optics Debuts at CES 2015: TVs with OLED-quality color at an affordable price coming soon to the US and Europe January 5th, 2015

Nanobiotechnology

DNA 'glue' could someday be used to build tissues, organs January 14th, 2015

Photonic crystal nanolaser biosensor simplifies DNA detection: New device offers a simpler and potentially less expensive way to detect DNA and other biomolecules through changes in surface charge density or solution pH January 13th, 2015

Determination of Critical Force, Time for Manipulation of Biological Nanoparticles January 7th, 2015

DNA Origami Could Lead to Nano “Transformers” for Biomedical Applications: Tiny hinges and pistons hint at possible complexity of future nano-robots January 5th, 2015

Solar/Photovoltaic

New technique helps probe performance of organic solar cell materials January 23rd, 2015

Teijin to Participate in Nano Tech 2015 January 22nd, 2015

The path to artificial photosynthesis: HZB researchers describe efficient manganese catalyst capable of converting light to chemical energy January 21st, 2015

Self-assembled nanotextures create antireflective surface on silicon solar cells: Nanostructured surface textures-with shapes inspired by the structure of moths' eyes-prevent the reflection of light off silicon, improving conversion of sunlight to electricity January 21st, 2015

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE