Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nanoplasmonics: Towards efficient light harvesting

07.01.2014
The control of light is vital to many applications, including imaging, communications, sensing, cancer treatment, and even welding processes for automobile parts.

Transformation optics is an emerging field that has revolutionized our understanding of how to control light by constituting an effectively curved electromagnetic space.

This revolutionary strategy not only revisits the fundamental physics of light-matter interactions, but also renders trivial the design of optical functions that may otherwise be difficult or virtually impossible, such as an "invisibility cloak," which could only previously be found in science fiction.

When compared with ray optics, the new transformation optics technique provides a picture that is equally intuitive, but that is much more accurate in its description of the wave nature of light by using the electric and magnetic field lines as its basis. Therefore, the validity of this method is not restricted to the macroscopic regime, but can also be extended to the subwavelength scale. In a recent review paper published by SCIENCE CHINA Information Sciences, Yu Luo and colleagues from Imperial College London illustrate how the general capabilities of the transformation optics technique can be used to treat the subwavelength fields that occur in plasmonic systems and review the latest developments in transformation optics as applied to nanophotonics.

In plasmonics, metallic structures with sharp corners can trap light into nanometric volumes, thus giving rise to strong near-field enhancements. This effect can be used to detect single molecules, generate high harmonic signals, and even improve absorption in photovoltaic devices. Further developments using these techniques need to be guided by accurate and versatile theoretical modeling. However, modeling of this type can be difficult, because various aspects associated with the sharp plasmonic structures can hinder provision of accurate and convenient solutions to the problem at hand. First, the size of the sharp metallic point structure is normally much smaller than that of the device overall, which makes it difficult to create meshes for numerical simulations. Second, the strong contrast in the dielectric functions at the metal-dielectric interfaces leads to slow convergence of the field expansions. Yu Luo and colleagues deploy the theory of transformation optics to circumvent these problems. Their idea is to transform a complex plasmonic system with little intrinsic geometrical symmetry into a canonical structure with translational or rotational symmetry, which is then relatively easy to study using conventional theory.

For example, two touching nanowires can be transformed into two flat metal surfaces that are separated by a gap, and a sharp metal edge can be related to a periodic array of metal slabs. Other structures that can be studied using transformation optics include pairs of metallic nanospheres, asymmetric core-shell structures and rough metal surfaces. In fact, using transformation optics techniques, we could reverse engineer the optical properties of complex plasmonic nanostructures and redesign these structures based on the requirements of the desired applications.

Practical issues with the realization of plasmonic devices, such as the effects of edge rounding at sharp boundaries on the local field enhancement and resonance properties, can also be considered theoretically using transformation optics and provide useful guidance for the fabrication of these devices. In particular, the necessary conditions are highlighted for both broadband light absorption effects and large field enhancements. Experimental evidence for phenomena that have been predicted by transformation optics has also been reviewed, indicating potential applications in biosensing and broadband solar photovoltaics. These studies demonstrate the accuracy and versatility of transformation optics methods and are expected to encourage more researchers to enter this field.

Corresponding author:

LUO Yu
y.luo09@imperial.ac.uk
See the article: Luo Y, Zhao R K, Fernandez-Dominguez A I, et al. Harvesting light with transformation optics. Sci China Inf Sci, 2013, 56(12): 120401(13).

http://info.scichina.com:8084/sciFe/EN/abstract/abstract512908.shtml

Science China Press Co., Ltd. (SCP) is a scientific journal publishing company of the Chinese Academy of Sciences (CAS). For 60 years, SCP takes its mission to present to the world the best achievements by Chinese scientists on various fields of natural sciences researches.

YAN Bei | EurekAlert!
Further information:
http://www.scichina.org

More articles from Information Technology:

nachricht Optical fiber transmits one terabit per second – Novel modulation approach
16.09.2016 | Technische Universität München

nachricht Researchers prototype system for reading closed books
09.09.2016 | Massachusetts Institute of Technology

All articles from Information Technology >>>

The most recent press releases about innovation >>>

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

Im Focus: OLED microdisplays in data glasses for improved human-machine interaction

The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.

“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...

Im Focus: Artificial Intelligence Helps in the Discovery of New Materials

With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.

Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...

Im Focus: Complex hardmetal tools out of the 3D printer

For the first time, Fraunhofer IKTS shows additively manufactured hardmetal tools at WorldPM 2016 in Hamburg. Mechanical, chemical as well as a high heat resistance and extreme hardness are required from tools that are used in mechanical and automotive engineering or in plastics and building materials industry. Researchers at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden managed the production of complex hardmetal tools via 3D printing in a quality that are in no way inferior to conventionally produced high-performance tools.

Fraunhofer IKTS counts decades of proven expertise in the development of hardmetals. To date, reliable cutting, drilling, pressing and stamping tools made of...

Im Focus: Launch of New Industry Working Group for Process Control in Laser Material Processing

At AKL’16, the International Laser Technology Congress held in May this year, interest in the topic of process control was greater than expected. Appropriately, the event was also used to launch the Industry Working Group for Process Control in Laser Material Processing. The group provides a forum for representatives from industry and research to initiate pre-competitive projects and discuss issues such as standards, potential cost savings and feasibility.

In the age of industry 4.0, laser technology is firmly established within manufacturing. A wide variety of laser techniques – from USP ablation and additive...

Im Focus: New laser joining technologies at ‘K 2016’ trade fair

Every three years, the plastics industry gathers at K, the international trade fair for plastics and rubber in Düsseldorf. The Fraunhofer Institute for Laser Technology ILT will also be attending again and presenting many innovative technologies, such as for joining plastics and metals using ultrashort pulse lasers. From October 19 to 26, you can find the Fraunhofer ILT at the joint Fraunhofer booth SC01 in Hall 7.

K is the world’s largest trade fair for the plastics and rubber industry. As in previous years, the organizers are expecting 3,000 exhibitors and more than...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Experts from industry and academia discuss the future mobile telecommunications standard 5G

23.09.2016 | Event News

ICPE in Graz for the seventh time

20.09.2016 | Event News

Using mathematical models to understand our brain

16.09.2016 | Event News

 
Latest News

Chains of nanogold – forged with atomic precision

23.09.2016 | Life Sciences

New leukemia treatment offers hope

23.09.2016 | Health and Medicine

Self-assembled nanostructures hit their target

23.09.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>