Sir John Pendry Brings us the Perfect Lens

Sir John Pendry, Chair in Theoretical Solid State Physics at Imperial College, London, will deliver the 2007 William Gould Dow Distinguished Lecture, “The Perfect Lens: Resolution Beyond the Limits of Wavelength,” Tuesday, February 6, 4:30 p.m., at Chesebrough Auditorium, Chrysler Center, North Campus.

Pendry’s theoretical work in the area of metamaterials, man-made materials that are specially created to evoke unique physical properties, has led to a prescription for an optical lens that will be able to focus on features significantly smaller than the wavelength of light.

With natural materials, the resolution of a lens is limited to the order of the wavelength. However, nearly 40 years ago, Russian scientist Victor Veselago predicted remarkable optical capabilities from a material that had a negative refractive index (NRI). In such materials, light would be refracted, or bent, in an opposite way to that seen in nature.

The only problem was such a material was not know to exist in nature. After searching for such a material for years, interest waned, until the mid 1990’s when Sir John Pendry, in collaboration with scientists at Marconi Materials Technology in England, thought to create a man-made material with the desired electromagnetic properties. These metamaterials would derive their properties from their structure, rather than the atomic and molecular constituents. The microstructure in turn can be engineered to exhibit exotic electromagnetic properties. Researchers experimentally demonstrated an NRI metamaterial which operated in the microwave range in 2000.

“These metamaterials promise to turn optics upside down by breaking through the limits on resolution imposed by conventional technology,” said Pendry. In 2000, he theoretically predicted that a slab of negative index material could act as a superlens capable of perfect resolution. His perfect lens concept attracted tremendous interest to the field of metamaterials and the lens’ implementation has become the subject of an intense research effort.  

This same type of metamaterial is predicted to have enormous potential in the field of optical data storage, and lithography. More recently, Pendry and colleagues David Smith and David Schurig at Duke University introduced a new and exciting application of metamaterials: invisibility cloaks. They have formulated a general prescription for developing metamaterial shells that render objects placed within them invisible for a given wavelength of operation.

In a recent article in Scientific American, Pendry credits EECS assistant professor Tony Grbic and U-M EECS alumnus and U. Toronto professor George Eleftheriades with proving experimentally that a superlens could be built. Grbic, a member of the Radiation Laboratory since 2006, and his research group are currently investigating new approaches to developing NRI materials to broaden their application. They are also developing metamaterial-based rf/microwave devices such as phase shifters, filters, antennas and antenna feed networks.  Grbic predicts that negative index lenses at microwave frequencies will lead to improved medical imaging devices, new sensor technologies, wireless components, antennas, and microwave devices.

Also, an interdisciplinary team of faculty from the U-M College of Engineering have recently received a $5M five-year grant from the Department of Defense to develop NRI metamaterials. They include the team’s leader, Physics and EECS professor Roberto Merlin, EECS and Physics professor and U-M Vice President for Research, Stephen Forrest, and Materials Science & Engineering professors Rachel Goldman and Jinsang Kim. One of their goals is to create a superior metamaterial that will act as Pendry’s superlens, replacing the traditional curved lens to image extremely small, even nanoscale objects. At the same time, they will advance the science in the area of NRI metamaterials. As part of a Multidisciplinary University Research Initiative (MURI) program, they are partnering with 4 other institutions.

Pendry received the knighthood in 2004 for his services to science, and the 2005 Descartes Research Prize for “Extending Electromagnetism through Novel Artificial Materials.” Reflecting about future applications for metamaterials, Pendry stated, “I believe that the really valuable applications have yet to be dreamt of.”

The lecture is sponsored by the University of Michigan Department of Electrical Engineering and Computer Science. The lecture is free and open to the public. A reception will immediately follow the lecture.