Monday, October 17, 2005Volume 5, Issue 6
Visiting Japanese Scientist Studies New Materials
Masato Iwasaki is a visiting scientist from NGK Spark Plug in Japan, working in the Center for Dielectric Studies on low temperature co-fired ceramics and metamaterials. NGK is the world’s largest maker of automotive spark plugs, with over $2 billion in annual sales, but it is also a competitor in a number of other areas that utilize ceramic materials, including filters for cell phones, biomedical ceramics, oxygen sensors, and semiconductor components.
The field of metamaterials is brand new and there is still not a great deal known about the material, Mr. Iwasaki says. "The theory is going forward, and experiment is following," he explains.
The theoretical framework for these novel materials was proposed in a 1968 paper by Russian physicist Victor Veselago, who speculated that a material with a negative electric permittivity and negative magnetic permeability would have properties unlike any material known in nature. These so-called "negative index materials" would bend light in the opposite direction as predicted by Snell’s Law. Veselago suggested that a negative index lens made of metamaterial could focus much more electromagnetic detail than ordinary lenses, including evanescent waves that carry information smaller than electromagnetic wavelength.
The first experiments to show negative refraction were not done until 2001, at the University of California, San Diego, by David R. Smith and colleagues. The results raised a storm of controversy among scientists who believed that negative refraction violated Einstein’s speed of light barrier. They argued that there were good theoretical reasons why no left-handed materials were found in nature. In 2003, Andrew Houck and colleagues at MIT repeated and confirmed the negative-refraction experiments, and since that time, dozens of labs around the world have jumped into researching the properties of metamaterials.
Metamaterials rely for their special effects on the way the material is structured rather than on the inherent properties of the elements. The first metamaterials look like a circuit board, or like playing cards standing on end with squares and lines printed on their surface. The lines are wires and split ring resonators that are created using the same photolithographic techniques as conventional microchips.
Although still several years away from practical applications, metamaterials offer rich possibilities for enhancing the power of cell phones, for microwave imaging (MRI) of the human body in finer detail, and for fine tuning photolithography for computer chip manufacturing.
Asked why NGK sent him to Penn State, Iwasaki responds, "My company is researching in new fields, and Penn State is very good for research in materials, both in pure research and in applications. My resonators will be used in filters for cell phones for improved filtering. The trend is to higher frequencies. The smaller the product the shorter the wavelength and the higher the frequency."
Mr. Iwasaki’s Ph.D. is from Tokyo University, where he studied microwave heating of ceramics. For the past 18 months he has worked with Mike Lanagan and Clive Randall in the Center for Dielectric Studies in the Material Research Institute. "It has been very pleasant here," he says. "I have gotten a lot of knowledge about components and antennas. Working in Japan is very busy. There is no time just for gathering fundamental information."
He will be at Penn State for the next six months before returning to NGK’s R&D center. "I’m not sure what I will be doing when I return to Japan," he says. "There are so many areas of research going on there." His time at Penn State has given him a two-year break to learn about new materials that could have a big impact on our future.
