Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Sculptured materials allow multiple channel plasmonic sensors

11.11.2009
Sensors, communications devices and imaging equipment that use a prism and a special form of light -- a surface plasmon-polariton -- may incorporate multiple channels or redundant applications if manufacturers use sculptured thin films.

"Everyone uses surface plasmon resonance sensors. They are a multi billion-dollar industry worldwide," said Akhlesh Lakhtakia, the Charles Godfrey Binder (Endowed) professor of engineering science and mechanics, Penn State. "This type of sensor provides a fairly quick way to see what you have. It can tell you the concentration of chemicals, but in order to test for more than one chemical today, manufacturers have to use more than one sensor."

Surface plasmon resonance devices currently have a wide range of applications. They are commercially used as sensors for humidity, temperature, chemical concentrations and chemical composition. SPR devices can be used in a form of surface microscopy, as wave guides and tunable filters. Creating two or more channels in each device would multiply SPR utility in all areas of application.

Surface plasmon-polaritons are electromagnetic waves that flow along a sandwich of a metal and a dielectric. When light shines through a prism onto the sandwich, electrons form a cloud or plasma in the metal and the molecules of the dielectric get stretched or polarized. Under special conditions, a plasmon-polariton combination forms and moves as a single unit along the sandwich. The formation can be disturbed by the presence of an additional chemical in the dielectric. The disturbance provides the sensing principle. Useful as they are, each sensor can only detect one chemical for each prism and sandwich.

In a series of papers Lakhtakia and his colleagues report on their theoretical and experimental investigation into the possibility of propagating more than one surface plasmon-polariton wave of the same color on a substrate. They recently reported on their experimental work in the Journal of Nanophotonics and the journal Electonic Letters.

The theoretical work indicated that for one wavelength or color of light, it should be possible to generate not just one, but up to three possible plasmon-polaritons if the dielectric used is not a traditional material, but a periodically non-homogeneous sculptured nematic thin film.

"Just because the mathematics suggest three possible surface plasmon-polariton waves does not mean that they can actually all be created," said Lakhtakia. "We had to find someone who could produce the thin films that we needed to test the possibilities experimentally."

Yi-Jun Jen, professor and chair, and Chia-Feng Lin, graduate student, both of the department of electro-optical engineering, National Taipei University of Technology, fabricated the sculptured nematic thin films that were then used in a standard Kretschmann surface plasma resonance sensor configuration. The researchers found that they produced three surface plasmon-polariton waves of light with the same wavelength or color, but with three different speeds. Two of these were polarized in one direction -- p polarized -- and the third was polarized in the other direction - s polarized.

"This would allow us to test more than two things or to test for the same thing twice in order to reduce sensing errors," said Lakhtakia.

The key to this finding is that sculptured thin films are not the same structure along their thickness. Instead, the pattern of sculpturing does periodically repeat. This periodicity allows the production of two or more surface waves of the same wavelength.

Lakhtakia, working with Devender, an international undergraduate research intern and Drew Patrick Pulsifer, graduated student in engineering science and mechanics, next tried a chiral sculptured thin film. Chiral thin films are similar to periodic sculptured nematic thin films but are like a multitude of parallel corkscrews. Using these thin films the researchers generated two surface plasmon-polaritons waves, but with different speeds, both with p-polarized light.

"If this approach can be optimized and commercialized, there are exciting prospects in store for plasmonic-based sensing, imaging and communications," said Lakhtakia.

A'ndrea Elyse Messer | EurekAlert!
Further information:
http://www.psu.edu

More articles from Power and Electrical Engineering:

nachricht Stretchable biofuel cells extract energy from sweat to power wearable devices
22.08.2017 | University of California - San Diego

nachricht Laser sensor LAH-G1 - optical distance sensors with measurement value display
15.08.2017 | WayCon Positionsmesstechnik GmbH

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Cholesterol-lowering drugs may fight infectious disease

22.08.2017 | Health and Medicine

Meter-sized single-crystal graphene growth becomes possible

22.08.2017 | Materials Sciences

Repairing damaged hearts with self-healing heart cells

22.08.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>