Transient Enhancement and Spectral Narrowing of The Photothermal Effect of Plasmonic Nanoparticles Under Pulsed Excitation - Rice University researchers show short laser pulses selectively heat gold nanoparticles.
HOUSTON – (Jan. 3, 2013) – Plasmonic gold nanoparticles make pinpoint heating on demand possible. Now Rice University researchers have found a way to selectively heat diverse nanoparticles that could advance their use in medicine and industry.
Rice scientists led by Dmitri Lapotko and Ekaterina Lukianova-Hleb showed common gold nanoparticles, known since the 19th century as gold colloids, heat up at near-infrared wavelengths as narrow as a few nanometers when hit by very short pulses of laser light. The surprising effect reported in Advanced Materials appears to be related to nonstationary optical excitation of plasmonic nanoparticles. Plasmons are free electrons on the surface of metals that become excited by the input of energy, typically from light. Moving plasmons can transform optical energy into heat.
"The key idea with gold nanoparticles and plasmonics in general is to convert energy," Lapotko said. "There are two aspects to this: One is how efficiently you can convert energy, and here gold nanoparticles are world champions. Their optical absorbance is about a million times higher than any other molecules in nature.
The National Institutes of Health supported the research.
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