Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mathematical analysis: It may not be possible to create ’perfect lens’

29.09.2004


Researchers at Purdue University and the Massachusetts Institute of Technology have completed a mathematical analysis showing that it isn’t quite possible to build a so-called "perfect lens," but the underlying theory still makes it feasible to design better imaging systems.



A perfect lens would be able to focus light more narrowly than conventional lenses, making it possible to etch finer electronic circuits and create more compact and powerful computer chips. Such lenses also might lead to better fiberoptic communications systems and more precise medical imaging technologies.

Researchers have now shown, through rigorous mathematical analysis, that a perfect lens is not possible, said Kevin J. Webb, a professor of electrical and computer engineering at Purdue. "It may be possible to build a better imaging system, but it could never be perfect," Webb said. "That’s the bottom line."


The findings are detailed in a paper appearing online this week in Physical Review E, a journal published by the American Physical Society. The paper was written by Webb, Purdue engineering doctoral student Ming-Chuan Yang, MIT doctoral student David Ward and Keith Nelson, a professor of physical chemistry at MIT.

Perfect lenses theoretically could compensate for the loss of a portion of the light transmitting an image as it passes through a lens. Lenses and imaging systems could be improved if this lost light, which scientists call "evanescent light," could be restored.

Central to the concept of a perfect lens is the phenomenon called refraction, which occurs when electromagnetic waves, including light, bend slightly when passing from one material into another. Refraction causes the bent-stick-in-water effect, which occurs when a stick placed in a glass of water appears bent when viewed from the outside. Each material has its own "refraction index," which describes how much light will bend in that particular material.

All natural materials, such as glass, air and water, have positive refractive indices. In the late 1960s, researchers hypothesized what would happen if a material had a negative refractive index. At the interface between a material with a positive index and a material with a negative index, light would bend in the opposite direction. In 2000, researcher John Pendry at the Imperial College, London, theorized that slabs of such material might be used to create a perfect lens. The idea was that an imaging system that used a combination of positive and negative refraction could restore the lost evanescent light.

No materials have yet been created that have negative refraction indices for visible light, but in 2001 researchers at the University of California, San Diego, used combinations of copper rings and wires to cause a microwave beam to undergo negative refraction, enlivening the debate about the possibility of perfect lenses. "Through a rigorous mathematical analysis, however, we have been able to show that, while a negative refraction index could conceivably be used to build better imaging systems, a perfect lens is not possible," Webb said.

The research was supported in part by the U.S. Army Research Office and the National Science Foundation. "It’s always useful to use effects found either in nature or in fabricated structures to improve optical systems," said Fil Bartoli, a program director in the Electrical and Communications Systems Division within the NSF’s Engineering Directorate. "But any time you employ some cute effect, such as negative refraction, it’s important to quantify it and to determine to what extent it could be useful. "That is what Dr. Webb and his colleagues tried to do, and I think that they succeeded in quantifying it and making a useful statement."

The concept of using materials with negative refractive indices to improve imaging systems is likely to receive continued attention in the years to come, he said. "It’s a topical area that has a fair amount of interest in the scientific and engineering communities and still needs to be investigated," Bartoli said.

Emil Venere | EurekAlert!
Further information:
http://www.purdue.edu

More articles from Studies and Analyses:

nachricht Win-win strategies for climate and food security
02.10.2017 | International Institute for Applied Systems Analysis (IIASA)

nachricht The personality factor: How to foster the sharing of research data
06.09.2017 | ZBW – Leibniz-Informationszentrum Wirtschaft

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Salmonella as a tumour medication

HZI researchers developed a bacterial strain that can be used in cancer therapy

Salmonellae are dangerous pathogens that enter the body via contaminated food and can cause severe infections. But these bacteria are also known to target...

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

3rd Symposium on Driving Simulation

23.10.2017 | Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

 
Latest News

Microfluidics probe 'cholesterol' of the oil industry

23.10.2017 | Life Sciences

Gamma rays will reach beyond the limits of light

23.10.2017 | Physics and Astronomy

The end of pneumonia? New vaccine offers hope

23.10.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>