Tiny rulers to measure nanoscale structures

August 31, 2010
In contrast to a conventional nanoparticle dimer plasmon ruler, this new one shows an approximately linear relationship between the resonance wavelength shifts and nanosphere dimer interparticle separation for a linear plasmon ruler.

With the advent of nanometer-sized machines, there is considerable demand for stable, precise tools to measure absolute distances and distance changes. One way to do this is with a plasmon ruler. In physics jargon, a "plasmon" is the quasiparticle resulting from the quantization of plasma oscillation; it's essentially the collective oscillations of the free electron gas at a metallic surface, often at optical frequencies.

A noble metallic dimer (a molecule that results from combining two entities of the same species) has been used as a plasmon ruler to make absolute distance and distance change measurements.

Physicists at China's Wuhan University discovered that combined with a nanorod dimer could be used to solve the problem of measurement sensitivity. They provide details about their findings in the American Institute of Physics' .

Shao-Ding Liu and Mu-Tian Cheng used a nanostructure as a linear plasmon ruler. Nanospheres were used to modify surface plasmon coupling of a nanorod dimer. They found that the resonance wavelength shift increases approximately linearly with the increasing of a nanosphere's interparticle separations -- resulting in a structure that's useful as a plasmon ruler with homogenous measurement sensitivity.

"A nanoparticle dimer plasmon ruler possesses many advantages because its measurement sensitivity is homogeneous, it can operate in the near-infrared region, and the structure's size and nanorod aspect ratio can be modified freely to get the desired measurement range and sensitivity," notes Liu.

Applications for the linear plasmon ruler extend beyond studies of optical properties of metallic nanostructures to single-molecule microscopy, surface-enhanced Raman spectroscopy, waveguiding and .

Explore further: Panasonic Develops VCSEL Laser with Surface Plasmon Mirrors

More information: The article, "Linear plasmon ruler with tunable measurement range and sensitivity" by Shao-Ding Liu and Mu-Tian Cheng will appear in the Journal of Applied Physics. jap.aip.org/resource/1/japiau/v108/i3/p034313_s1

Related Stories

Visualizing viruses: new research pinpoints tiny invaders

August 24, 2010

In the war against infectious disease, identifying the culprit is half the battle. Now, research professor Shaopeng Wang and his colleagues from the Biodesign Institute at Arizona State University, describe a new method for ...

Recommended for you

Physicists develop new technique to fathom 'smart' materials

November 26, 2015

Physicists from the FOM Foundation and Leiden University have found a way to better understand the properties of manmade 'smart' materials. Their method reveals how stacked layers in such a material work together to bring ...

Mathematicians identify limits to heat flow at the nanoscale

November 24, 2015

How much heat can two bodies exchange without touching? For over a century, scientists have been able to answer this question for virtually any pair of objects in the macroscopic world, from the rate at which a campfire can ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.