Taming tiny, unruly waves for n...( ATLANTA (Oct. 8 2007) -- Nanoscale d...)

ATLANTA (Oct. 8, 2007) -- Nanoscale devices present a unique challenge to any optical technology -- theres just not enough room for light to travel in a straight line.

On the nanoscale, energy may be produced by radiating photons of light between two surfaces very close together (sometimes as close as 10 nanometers), smaller than the wavelength of the light. Light behaves much differently on the nanoscale as its wavelength is interrupted, producing unstable waves called evanescent waves. The direction of these unpredictable waves cant be calculated, so researchers face the daunting task of designing nanotechnologies to work with the tiny, yet potentially useful waves of light.

Researchers at Georgia Tech have discovered a way to predict the behavior of these unruly waves of light during nanoscale radiation heat transfer, opening the door to the design of a spectrum of new nanodevices (or NEMS) and nanotechnologies, including solar thermal energy technologies. Their findings were featured on the cover of the Oct. 8 issue of Applied Physics Letters.

This discovery gives us the fundamental information to determine things like how far apart plates should be and what size they should be when designing a technology that uses nanoscale radiation heat transfer, said Zhuomin Zhang, a lead researcher on the project and a professor in the Woodruff School of Mechanical Engineering. Understanding the behavior of light at this scale is the key to designing technologies to take advantage of the unique capabilities of this phenomenon.

The Georgia Tech research team set out to study evanescent waves in nanoscale radiation energy transfer (between two very close surfaces at different temperatures by means of thermal radiation). Because the direction of evanescent waves is seemingly unknowable (an imaginary value) in physics terms, Zhangs group instead decided to follow the direction of the electromagnetic energy flow (also known as a Poynting
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