Holograms are more than pretty pictures — they might also be key to new computing technologies, and it starts with the fine control of light itself.
At Purdue University, a group of electrical and computer engineers made a tiny hologram of the word “PURDUE” float only a few thousandths of an inch above a sheet of gold.
They created it using gold foil only a few nanometers thick folded into thousands of tiny, V-shaped antennas. Next, they shined a laser light through the foil layer, called a metasurface, which scattered the light waves in a very specific way producing the hologram of the letters.
Shaping letters out of light is all very well, but the real accomplishment was their ability to control the light. By changing the shape of the metasurface — the V-shaped antennas — the scientists found they could control the intensity and phase, or timing, of individual light waves. That control could translate into transmitting digital information superfast.
Currently, digital information is transmitted inside computer chips using electrons. But electrons are limited to moving at about a third the speed of light.
A metasurface technology could deliver information at the speed of light. That’s because the data would travel in light instead of electrons.
What’s also cool, is that the metasurface from Purdue is small enough to fit into the current crop of microchips. Until now, other optical devices have been too big.
The invention, detailed in the journal Nature Communications, was built by by former Purdue doctoral student Xingjie Ni, now a postdoctoral researcher at the University of California, Berkeley; Alexander Kildishev, associate professor of electrical and computer engineering at Purdue and Vladimir M. Shalaev, scientific director of nanophotonics at the university’s Birck Nanotechnology Center.
via Purdue University, Nature Communications
Credit: Xingjie Ni, Birck Nanotechnology Center