Shape shifters

Scientists at the University of Michiganhave developed a way to make a lens-like device focus electromagnetic waves with pinpoint accuracy.

According to Roberto Merlin, professor of physics at UM, materials respond differently to different wavelengths, and when using electromagnetic waves, the length of the light wave can limit the focus accuracy.

For example, the amount of information that can be stored on a CD is limited by the number of bits that can be fitted on the CD, and the length of the electromagnetic wave dictates this. The smaller the wavelength, therefore, the smaller the bit, which means that more bits of data could be stored on the CD.

Using mathematical models, Merlin developed a formula to remove the wavelength limitation.

A device, resembling a plate or a disc, is etched with a specific pattern. As the waves pass through the patterned lens, it reshapes the waves into different sizes and shapes, rather than refracts them, which is how conventional lenses work.

According to the researchers, the technology could make a CD hold up to 100 times more information by using terahertz radiation rather than visible light, even though terahertz waves are 1000 times longer. Other uses could be data storage, non-contact sensing, imaging, and nanolithography.