Tiny rulers to measure nanoscale structures

Aug 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: New absorber will lead to better biosensors

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

Provided by American Institute of Physics

not rated yet

Related Stories

Visualizing viruses: new research pinpoints tiny invaders

Aug 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

New absorber will lead to better biosensors

22 hours ago

Biological sensors, or biosensors, are like technological canaries in the coalmine. By converting a biological response into an optical or electrical signal, they can alert us to dangers in our external and internal environments. ...

Ultrafast remote switching of light emission

Sep 30, 2014

Researchers from Eindhoven University of Technology can now for the first time remotely control a miniature light source at timescales of 200 trillionth of a second. They published the results on Sept. 2014 ...

Nanotube cathode beats large, pricey laser

Sep 30, 2014

Scientists are a step closer to building an intense electron beam source without a laser. Using the High-Brightness Electron Source Lab at DOE's Fermi National Accelerator Laboratory, a team led by scientist ...

User comments : 0