| Plasmon resonance (2) |  |
Roughly speaking plasmons are ripples of electrons on an electrically conducting surface. Light shines on a metal and its plasmons can reradiate specific colors.
Some of the colors in stained-glass windows at cathedrals like Notre dame are produced by the plasmons in tiny particles of gold reflecting light
and producing an extremely vivid color. That is not how most color is produced now. When you look at a picture of a red flower on paper there is a pigment chemical that absorbs each color--green and blue for instance
Metallic carbon nanotubes are expected to show plasmon resonance in the terahertz and infrared range but no group has demonstrated clearly the existence of plasmons in carbon nanotubes Zhang said.
Previously people proposed one possible explanation--that the terahertz peak is due to interband absorption in the small band gaps in semiconducting nanotubes.
Plasmons are free electrons on the surface of metals like gold silver or even aluminum nanoparticles that when triggered by a laser
Strong waves can trigger plasmon responses in adjacent nanoparticles. They are being investigated at Rice and elsewhere for use in sophisticated electronic and medical applications.
The Kono group's research showed plasmons rippling at terahertz frequencies only along the length of a nanotube but not across its width.
We will be making various terahertz devices architectures and systems based on carbon nanotube plasmons. Rice alumni Erik Há
while gold nanoparticles'plasmons resonate in visible wavelengths from 550 to 700 nanometers and silver from 350 to 700 aluminum can reach into the ultraviolet to about 200 nanometers.
In both cases quantum tunneling through the gap allowed plasmons to resonate as though the core
Plasmon-generated electrons timed moving from nanorods to grapheneplasmonic nanoparticles developed at Rice university are becoming known for their ability to turn light into heat
They suggest that the extraction of electrons generated by surface plasmons in metal nanoparticles may be optimized.
Plasmons are the collective excitation of free electrons in metals that when stimulated by an energy source like sunlight
In one practical example demonstrated at Rice plasmon excitation in gold nanoparticles produces heat that instantly turns even ice-cold water into steam.
The plasmon generates hot electrons that decay very quickly so intercepting them is a challenge he said.
The researchers placed gold nanorods on beds of both inert quartz and highly conductive graphene and used a spectrometer to view the line width of the plasmon-scattering spectrum.
The homogeneous line width obtained via single-particle spectroscopy is a measure of the range of wavelengths that resonantly excite a surface plasmon.
It's also a measure of the plasmon lifetime. Broad line widths correspond to short lifetimes and narrow line widths to long lifetimes.
The Rice researchers found graphene broadened the nanorods'surface plasmon response --and shortened its lifetime--by accepting hot electrons.
By acting as an electron acceptor the graphene accelerated damping of the plasmons. The difference in damping between the quartz
The plasmon resonance is determined by the size and the shape of the nanoparticle Hoggard said. And it usually appears as a single peak for gold nanorods.
and also as an analytical tool for observing such plasmon-enabled reactions. That's the big picture.
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