- About Us
- Career Center
- Nano-Social Network
- Nano Consulting
- My Account
|Concept art depicting the various potential BNA trapping states|
University of Illinois researchers have shown that by tuning the properties of laser light illuminating arrays of metal nanoantennas, these nano-scale structures allow for dexterous optical tweezing as well as size-sorting of particles.
"Nanoantennas are extremely popular right now because they are really good at concentrating optical fields in small areas," explained Kimani Toussaint, Jr., an assistant professor of mechanical science and engineering at the University of Illinois at Urbana-Champaign. "In this work, we demonstrate for the first time the use of arrays of gold Bowtie Nanoantenna Arrays (BNAs) for multipurpose optical trapping and manipulation of submicrometer- to micrometer-sized objects. We think that this could be a fruitful area to pursue, particularly because of the growing interest in lab-on-a-chip devices."
According to the researchers, the excellent field enhancement and confinement properties of BNAs enable highly efficient, optical tweezers which permit high-speed manipulation of submicrometer to micrometer-sized objects in aqueous environments using remarkably low-input power densities. These characteristics could be useful for optofluidic applications (e.g., lab-on-a-chip devices), manipulating biological matter with reduced specimen photo damage, formation of optical matter, and basic physics studies of colloidal dynamics.
"In contrast to other plasmonic tweezers, we find that BNAs permit particle trapping, manipulation and sorting utilizing only the optical parameter space, namely, low input power densities, wavelength and polarization," said Brian Roxworthy, a graduate student in Toussaint's research group and first author on the paper, "Application of Plasmonic Bowtie Nanoantenna Arrays for Optical Trapping, Stacking, and Sorting," which appears in the journal Nano Letters.
Using empirically obtained "optical trapping phase diagrams" to achieve the desired trapping response, the researchers demonstrated several types of particle manipulation, including single-beam optical tweezing of single particles over the entire nanoantenna area, single-beam optical tweezing of 2D hexagonal packed particles over the entire nanoantenna area, and optical sorting of particles by size; stacking of submicron to micron-sized particles in 3D.
According to Toussaint, this is the first demonstration of a range of particle manipulation behavior for a given nanoantenna array.
"We actually excite our nanoantennas off resonance, which to our knowledge is a first, and at the right input optical power, we take advantage of thermal effects combined with optical forces to enable tweezing of tens of particles at a time," Toussaint explained. "We show that very low power densities are required to achieve the aforementioned behavior. For example, we were able to carry out experiments using a standard laser pointer."
In addition to Toussaint, the lead investigator for the project, co-investigators include Gang Logan Liu, an assistant professor of electrical and computer engineering at Illinois, and former Illinois faculty member Nicholas Fang, who is now at the Massachusetts Institute of Technology.
For more information, please click here
Kimani C. Toussaint, Jr.
Department of Mechanical Science & Engineering
If you have any questions about the
College of Engineering
or other story ideas, contact
Engineering Communications Office
University of Illinois at Urbana-Champaign.
Copyright © University of Illinois at Urbana-ChampaignIf you have a comment, please Contact us.
Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
|Related News Press|
News and information
Researchers refine method for detecting quantum entanglement June 18th, 2016
Artificial molecules April 3rd, 2016
New microwave imaging approach opens a nanoscale view on processes in liquids: Technique can explore technologically and medically important processes that occur at boundaries between liquids and solids, such as in batteries or along cell membranes March 16th, 2016
Nanoworld 'snow blowers' carve straight channels in semiconductor surfaces: NIST, IBM researchers report important addition to toolkit of 'self-assembly' methods eyed for making useful devices December 28th, 2015
FEI Launches Helios G4 DualBeam Series for Materials Science: The Helios G4 DualBeam Series features new capabilities to enable scientists and engineers to answer the most demanding and challenging scientific questions June 27th, 2016
Marrying superconductors, lasers, and Bose-Einstein condensates: Chapman University Institute for Quantum Studies (IQS) member Yutaka Shikano, Ph.D., recently had research published in Scientific Reports June 20th, 2016
A new trick for controlling emission direction in microlasers June 20th, 2016