U. of Illinois researchers measure near-field behavior of semiconductor plasmonic microparticles

Nanometer-scale heating reveals surface plasmon resonance

2013-04-22

(Press-News.org) Recent progress in the engineering of plasmonic structures has enabled new kinds of nanometer-scale optoelectronic devices as well as high-resolution optical sensing. But until now, there has been a lack of tools for measuring nanometer-scale behavior in plasmonic structures which are needed to understand device performance and to confirm theoretical models.

"For the first time, we have measured nanometer-scale infrared absorption in semiconductor plasmonic microparticles using a technique that combines atomic force microscopy with infrared spectroscopy," explained William P. King, an Abel Bliss Professor in the Department of Mechanical Science and Engineering (MechSE) at Illinois. "Atomic force microscope infrared spectroscopy allows us to directly observe the plasmonic behavior within microparticle infrared antennas."

The article describing the research, "Near-field infrared absorption of plasmonic semiconductor microparticles studied using atomic force microscope infrared spectroscopy," appears in Applied Physics Letters.

"Highly doped semiconductors can serve as wavelength flexible plasmonic metals in the infrared," noted Daniel M. Wasserman, assistant professor of electrical and computer engineering at Illinois. "However, without the ability to visualize the optical response in the vicinity of the plasmonic particles, we can only infer the near-field behavior of the structures from their far-field response. What this work gives us is a clear window into the optical behavior of this new class of materials on a length scale much smaller than the wavelength of light."

The article compares near-field and far-field measurements with electromagnetic simulations to confirm the presence of localized plasmonic resonance. The article further reports high resolution maps of the spatial distribution of absorption within single plasmonic structures and variation across plasmonic arrays.

"The ability to measure near field behavior in plasmonic structures allows us to begin expanding our design parameters for plasmonic materials," commented Jonathan Felts, a MechSE graduate student. "Now that we can measure the optical behavior of individual features, we can start to think about designing and testing more complex optical materials."

INFORMATION:

The authors on the research are Jonathan Felts, Stephanie Law, Daniel M. Wasserman, and William P. King of the University of Illinois at Urbana-Champaign, along with Christopher M. Roberts and Viktor Podolskiy of the University of Massachusetts. The article is available at http://apl.aip.org/resource/1/applab/v102/i15/p152110_s1. This research was supported by the National Science Foundation.

Contact: William King, Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 217/244-3864

ELSE PRESS RELEASES FROM THIS DATE:

Using black holes to measure the universe's rate of expansion

2013-04-22

A few years ago, researchers revealed that the universe is expanding at a much faster rate than originally believed — a discovery that earned a Nobel Prize in 2011. But measuring the rate of this acceleration over large distances is still challenging and problematic, says Prof. Hagai Netzer of Tel Aviv University's School of Physics and Astronomy. Now, Prof. Netzer, along with Jian-Min Wang, Pu Du and Chen Hu of the Institute of High Energy Physics of the Chinese Academy of Sciences and Dr. David Valls-Gabaud of the Observatoire de Paris, has developed a method with ...

40 percent of parents give young kids cough/cold medicine that they shouldn't

2013-04-22

ANN ARBOR, Mich. – Children can get five to 10 colds each year, so it's not surprising that adults often turn to over-the-counter cough and cold medicines to relieve their little ones' symptoms. But a new University of Michigan poll shows that many are giving young kids medicines that they should not use. More than 40 percent of parents reported giving their children under age 4 cough medicine or multi-symptom cough and cold medicine, according to the latest University of Michigan C.S. Mott Children's Hospital National Poll on Children's Health. Twenty-five percent gave ...

Genetic circuit allows both individual freedom, collective good

2013-04-22

HOUSTON -- (April 22, 2013) -- Individual freedom and social responsibility may sound like humanistic concepts, but an investigation of the genetic circuitry of bacteria suggests that even the simplest creatures can make difficult choices that strike a balance between selflessness and selfishness. In a new study the journal Scientific Reports, researchers from Rice University's Center for Theoretical Biological Physics (CTBP) and colleagues from Tel Aviv University and Harvard Medical School show how sophisticated genetic circuits allow an individual bacterium within ...

Rivers act as 'horizontal cooling towers,' study finds

2013-04-22

DURHAM, N.H. -– Running two computer models in tandem, scientists from the University of New Hampshire have detailed for the first time how thermoelectric power plants interact with climate, hydrology, and aquatic ecosystems throughout the northeastern U.S. and show how rivers serve as "horizontal cooling towers" that provide an important ecosystem service to the regional electricity sector — but at a cost to the environment. The analysis, done in collaboration with colleagues from the City College of New York (CCNY) and published online in the current journal Environmental ...

Fighting the 'dumb jock' stereotype

2013-04-22

EAST LANSING, Mich. — College coaches who emphasize their players' academic abilities may be the best defense against the effects of "dumb jock" stereotypes, a Michigan State University study suggests. Researchers found that student-athletes were significantly more likely to be confident in the classroom if they believed their coaches expected high academic performance, not just good enough grades to be eligible for sports. "Coaches spend a lot of time with their players, and they can play such an important role to build academic confidence in student-athletes," said ...

NASA sees 3 coronal mass ejections

2013-04-22

On April 20, 2013, at 2:54 a.m. EDT, the sun erupted with a coronal mass ejection (CME), a solar phenomenon that can send billions of tons of solar particles into space that can affect electronic systems in satellites. Experimental NASA research models show that the CME left the sun at 500 miles per second and is not Earth-directed. However, it may pass by NASA's Messenger and STEREO-A satellites, and their mission operators have been notified. There is, however, no particle radiation associated with this event, which is what would normally concern operators of interplanetary ...

Online biodiversity databases audited: 'Improvement needed'

2013-04-22

The records checked were for native Australian millipede species and were published online by the Global Biodiversity Information Facility, GBIF and the Atlas of Living Australia, ALA. GBIF and ALA obtain most of their records from cooperating museums, but disclaim any responsibility for errors in museum databases, instead warning users that the data may not be accurate or fit for purpose. The auditing was done voluntarily by Dr Bob Mesibov, who is a millipede specialist and a research associate at the Queen Victoria Museum and Art Gallery in Launceston, Tasmania. The ...

Is pet ownership sustainable?

2013-04-22

URBANA – There has been much talk about sustainability, but little attention has been paid to its nutritional aspects. University of Illinois animal sciences researcher Kelly Swanson, in cooperation with scientists at natural pet food maker The Nutro Company, have raised a number of important questions on the sustainability of pet ownership. Sustainability is defined as meeting the needs of the present while not compromising the future. Swanson said that although the carbon footprint aspect of sustainability receives the most attention, nutritional aspects are also important. ...

More accurate, powerful genetic analysis tool opens new gene-regulation realms

2013-04-22

SALT LAKE CITY—Researchers from Huntsman Cancer Institute (HCI) at the University of Utah have developed a novel and powerful technique to identify the targets for a group of enzymes called RNA cytosine methyltransferases (RMTs) in human RNA. They applied their technique to a particular RMT, NSUN2, which has been implicated in mental retardation and cancers in humans, finding and validating many previously unknown RMT targets—an indication of the technique's power. The research results were published online in the journal Nature Biotechnology on April 21. "Although RMTs ...

Facial dog bites in children may require repeated plastic surgery

2013-04-22

Philadelphia, Pa. (April 22, 2013) - Dog bites to the face are a relatively common injury in young children, and often require repeated plastic surgery procedures to deal with persistent scarring, according to a report in the March Journal of Craniofacial Surgery, published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health. In the study, Dr. Barry L. Eppley of Indiana University Health North Hospital, Carmel, and Dr. Arno Rene Schelich of Hans Privatklinikum, Graz, Austria, review a ten-year experience of the common dog bites of the face in children. "[R]egardless ...

LAST 30 PRESS RELEASES:

The Lancet Diabetes & Endocrinology: Higher doses of semaglutide can safely enhance weight loss and improve health for adults living with obesity, two new clinical trials confirm