Surface plasmon resonances of metal nanoparticles in array can have narrower spectral widths

November 14, 2008

Researchers at the Harvard School of Engineering and Applied Sciences (SEAS) have demonstrated experimentally and theoretically that the surface plasmon resonances of metal nanoparticles in a periodic array can have considerably narrower spectral widths than those of isolated metal nanoparticles. Further, as the optical fields are significantly more intense in a periodic array, the method could improve the sensitivity of detecting molecules at low concentrations.

While researchers have known that a group of nanoparticles could be used to increase signal levels for sensor applications, the electromagnetic interactions between the particles have often been overlooked. A team led by Ken Crozier, John L. Loeb Associate Professor of the Natural Sciences at SEAS, showed that by spacing a nanoparticle array appropriately, the interactions between nanoparticles can be optimized.

The study, published in the November 3 issue of Applied Physics Letters, was carried out by Yizhuo Chu, Ethan Schonbrun and Tian Yang under the direction of Professor Crozier, all of SEAS. "We used numerical electromagnetic simulations to design nanoparticle arrays exhibiting narrow surface plasmon resonance peaks and intense optical fields, and checked our predictions experimentally," said Crozier.

To do so, Crozier and his team fabricated the nanoparticle arrays using electron beam lithography on glass substrates. By measuring the optical transmission of collimated beams of white light through the arrays, the team found that their experimental results confirmed their original theoretical predictions of sharp plasmon resonance peaks.

"The narrow peaks occur when the product of the nanoparticle spacing and the refractive index of the surrounding medium approximately matches the plasmon resonance wavelength of a single nanoparticle," explained Crozier.

Over the past several years, Crozier and his colleagues have helped to advance the field of plasmonics, harnessing its ability to confine electromagnetic fields to deep sub-wavelength dimensions for spectroscopy, sensing and optical manipulation. The larger field enhancement demonstrated in their latest finding could be important for further refining surface enhanced Raman spectroscopy and for improving biosensors.

Source: Harvard University

4.2 /5 (9 votes)  

Rank 4.2 /5 (9 votes)
Tags

Relevant PhysicsForums posts
  • Thermodynamics q
    created4 hours ago
  • what is electricity???
    created8 hours ago
  • Can Plasma Be Solid
    created9 hours ago
  • What is delta Δ ?
    created9 hours ago
  • Need some help understanding Hertz–Knudsen formula
    created10 hours ago
  • Anatomy of Fat man: implosion-critical bomb
    created12 hours ago
  • More from Physics Forums - General Physics

More news stories

Explained: Sigma

It's a question that arises with virtually every major new finding in science or medicine: What makes a result reliable enough to be taken seriously? The answer has to do with statistical significance -- but ...

Physics / General Physics

created Feb 09, 2012 | popularity 5 / 5 (20) | comments 78

Quantum physicist explains $100K offer for proof scaled-up quantum computing is impossible

(PhysOrg.com) -- MIT researcher Scott Aaronson has certainly riled the physics community with his offer this past Friday, of $100,000 to anyone who can prove that scaled-up quantum computing is impossible. ...

Physics / Quantum Physics

created Feb 08, 2012 | popularity 4.3 / 5 (15) | comments 37 | with audio podcast weblog

Diamond light, brighter than the sun

It’s the size of five football pitches and generates light 10 billion times brighter than the sun. As the Diamond Light Source celebrates its tenth anniversary this year, Penny Bailey visits one of the ...

Physics / General Physics

created Feb 07, 2012 | popularity 4.1 / 5 (11) | comments 18 | with audio podcast

Physicists 'record' magnetic breakthrough

An international team of scientists has demonstrated a revolutionary new way of magnetic recording which will allow information to be processed hundreds of times faster than by current hard drive technology.

Physics / General Physics

created Feb 07, 2012 | popularity 4.6 / 5 (43) | comments 15 | with audio podcast

Hints of the Higgs - papers are submitted

Back in December 2011, the ATLAS and CMS experiments at CERN presented some exciting results that provided tantalising hints of the Higgs boson.

Physics / General Physics

created Feb 08, 2012 | popularity 4.3 / 5 (8) | comments 10


Japan's Fukushima reactor may be reheating: operator

Temperature readings at one of the crippled Fukushima nuclear reactors have risen above Japan's stringent new safety standard but there was no immediate danger, its operator said Sunday.

Integrated pest management recommendations for the southern pine beetle

The southern pine beetle, Dendroctonus frontalis Zimmermann, is a chronic insect pest within pine forests in the southeastern United States. Under favorable environmental and host conditions, it is an agg ...

Botox developer rues missing out on billions

Botox developer Alan Scott says he rues the day he handed over rights to the best-selling wrinkle-smoothing drug to a US company for just $4.5 million, saying he might have become a billionaire.

Australian women reject 'I love u' texts

Australian women may have embraced the digital era, but they prefer a face-to-face declaration of affection to an "I love u" text and find men addicted to their mobile phones a major turnoff.

Many lung cancer patients get radiation therapy that may not prolong their lives

A new study has found that many older lung cancer patients get treatments that may not help them live longer. Published early online in CANCER, a peer-reviewed journal of the American Cancer Society, the findings suggest that p ...

Young adults allowed to stay on parents' health insurance have improved access to care

Researchers from Mount Sinai School of Medicine have found that laws permitting children to stay on their parents' health insurance through age 26 result in improved access to health care compared to states without those ...