Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

android tablet pc

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

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

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.

Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Organometallics welcomes new editor-in-chief: Paul Chirik, Ph.D. July 22nd, 2014

The Hiden EQP Plasma Diagnostic with on-board MCA July 22nd, 2014

Iran to Hold 3rd Int'l Forum on Nanotechnology Economy July 22nd, 2014

Nanometrics Announces Upcoming Investor Events July 22nd, 2014

Possible Futures

IBM Announces $3 Billion Research Initiative to Tackle Chip Grand Challenges for Cloud and Big Data Systems: Scientists and engineers to push limits of silicon technology to 7 nanometers and below and create post-silicon future July 10th, 2014

Virus structure inspires novel understanding of onion-like carbon nanoparticles April 10th, 2014

Local girl does good March 22nd, 2014

Surface Characteristics Influence Cellular Growth on Semiconductor Material March 12th, 2014


Researchers create vaccine for dust-mite allergies Main Page Content: Vaccine reduced lung inflammation to allergens in lab and animal tests July 22nd, 2014

NIST shows ultrasonically propelled nanorods spin dizzyingly fast July 22nd, 2014

SentiMag® Now Available in Australia and New Zealand July 21st, 2014

More than glitter: Scientists explain how gold nanoparticles easily penetrate cells, making them useful for delivering drugs July 21st, 2014


Tiny laser sensor heightens bomb detection sensitivity July 19th, 2014

Iranian Scientists Use Nanosensors to Achieve Best Limit for Early Cancer Diagnosis July 19th, 2014

Rice nanophotonics experts create powerful molecular sensor: Sensor amplifies optical signature of single molecules about 100 billion times July 15th, 2014

University of Illinois researchers demonstrate novel, tunable nanoantennas July 14th, 2014


Nanometrics Announces Upcoming Investor Events July 22nd, 2014

Bruker Awarded Fourth PeakForce Tapping Patent: AFM Mode Uniquely Combines Highest Resolution Imaging and Material Property Mapping July 22nd, 2014

NIST shows ultrasonically propelled nanorods spin dizzyingly fast July 22nd, 2014

Penn Study: Understanding Graphene’s Electrical Properties on an Atomic Level July 22nd, 2014

Quantum Dots/Rods

Researchers create quantum dots with single-atom precision June 30th, 2014

New Los Alamos Approach May Be Key to Quantum Dot Solar Cells With Real Gains in Efficiency: Nanoengineering Boosts Carrier Multiplication in Quantum Dots June 19th, 2014

MIPT-based researcher predicts new state of matter June 17th, 2014

Technology using microwave heating may impact electronics manufacture June 10th, 2014


Production of Non-Virus Nanocarriers with Highest Amount of Gene Delivery July 17th, 2014

Physicists Use Computer Models to Reveal Quantum Effects in Biological Oxygen Transport: The team solved a long-standing question by explaining why oxygen – and not deadly carbon monoxide – preferably binds to the proteins that transport it around the body. July 17th, 2014

Tiny DNA pyramids enter bacteria easily -- and deliver a deadly payload July 9th, 2014

Artificial cilia: Scientists from Kiel University develop nano-structured transportation system July 4th, 2014


Steam from the sun: New spongelike structure converts solar energy into steam July 21st, 2014

Making dreams come true: Making graphene from plastic? July 2nd, 2014

Shrinky Dinks close the gap for nanowires July 1st, 2014

New Study Raises Possibility of Production of P-Type Solar Cells July 1st, 2014

The latest news from around the world, FREE

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

Nanotechnology Now Featured Books


The Hunger Project

© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE