Bending the Laws of Physics
Researchers receive $5.5 million to study new optical material
By Melissa Edler, ’00

The idea that the focusing power of optical elements comes from their shape and how light bends at the surface has been around since the first century. It wasn’t fully explained, however, until the 17th century, when physicists developed a theory behind the phenomenon and predicted that when electromagnetic radiation, such as light, passes between two media — like from air to water — it bends or refracts at a positive angle or to the right side.

Today, this rule, named Snell’s law, applies to every optical object, including traffic lights, headline ticker boards, microscopes, telescopes, camcorders and cameras.

Recently, though, scientists have discovered a new type of material called negative index materials (NIMs), which defy Snell’s law by bending light in the opposite direction. “These metamaterials are rewriting the laws of optics, because they bend light in a left-handed direction compared to their positive, right-handed counterparts,” says Dr. Oleg Lavrentovich, director of Kent State University’s Liquid Crystal Institute®.

Kent State researchers, along with a team of scientists from several other institutions, received a $5.5 million Multidisciplinary University Research Initiative (MURI) last April from the Air Force Office of Scientific Research to study these unique metamaterials.

The notion of negative index materials was considered wildly speculative and unrealizable when it was proposed more than 30 years ago. Recently, however, scientists have learned how to create NIMs in spectra invisible to the human eye.

As part of a five-year MURI project, Kent State researchers and their colleagues plan to break new ground by creating a negative index material for the visible and near-infrared spectrum of light.

The concept of a material with sub-wavelength resolution is revolutionary in the fields of science and technology. “The optical behavior of negative index materials is astonishing, and it opens the door to a wide variety of new and exciting applications,” says Dr. Peter Palffy-Muhoray, a Kent State professor of chemical- physics at the Liquid Crystal Institute and principal investigator of the project.

Lenses made from NIMs, which are not found anywhere in nature, have unique physical properties. A lens made from negative index materials could have resolution that is unlimited by wavelength. In addition, these metamaterials could reverse the Doppler effect, potentially creating zero reflectance from objects.

These negative index materials have the potential to improve devices in communications, electronics, optics and medicine. Specific applications include creating flat, apertureless imaging elements; “perfect” lenses with super resolution; nondestructive optical tweezers to manipulate biological cells; novel antennas; new beam steering devices; sensors; novel band gap materials; high-density optical storage; vast improvements to Magnetic Resonance Imaging (MRI) scanning; and the ability to store more information on products such as DVDs.

For more information about this research, visit the Liquid Crystal Institute Web site. You can also learn more about the Multidisciplinary University Research Initiative (MURI) from the Air Force Office Scientific Research Web site.