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 Smart Data Transformation – Surfing the Big Wave
02.12.2016 | Fraunhofer-Institut für Angewandte Informationstechnik FIT

nachricht Climate change could outpace EPA Lake Champlain protections
18.11.2016 | University of Vermont

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: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

High-precision magnetic field sensing

05.12.2016 | Power and Electrical Engineering

Construction of practical quantum computers radically simplified

05.12.2016 | Information Technology

NASA's AIM observes early noctilucent ice clouds over Antarctica

05.12.2016 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>