The speed at which light travels is crucial for rapid information exchange. However, if scientists could somehow slow down the speed of light particles, it would have a whole host of new technological applications that could be utilized for quantum computing, LIDAR, virtual reality, light-based WiFi, and even the detection of viruses.
Now, in a paper published in Nature Nanotechnology, Stanford scientists have demonstrated an approach to slow light significantly and direct it at will.
Scientists from the lab of Jennifer Dionne, associate professor of materials science and engineering at Stanford, developed These "high-quality-factor" or "high-Q" resonators by structuring ultrathin silicon chips into nanoscale bars so as to resonantly trap light and then release it, or redirect it at a later time.
"We're essentially trying to trap light in a tiny box that still allows the light to come and go from many different directions," Mark Lawrence, postdoctoral fellow and lead author of the paper, said in a press release. "It's easy to trap light in a box with many sides, but not so easy if the sides are transparent—as is the case with many Silicon-based applications."
To overcome this problem, the Stanford team developed an extremely thin layer of silicon, which is very efficient at trapping light and has low absorption in the near-infrared, the spectrum of light the researchers set out to control. This is now a central component of their device.
The silicon rests atop a wafer of transparent sapphire, into which the researchers direct an electron microscope "pen" in order to etch their nanoantenna pattern. It's crucial that the pattern is drawn as smoothly as possible, as imperfections inhibit their light-trapping ability.
"Ultimately, we had to find a design that gave good-light trapping performance but was within the realm of existing fabrication methods," Lawrence said.
One application the Stanford component could be used for is to split photons for quantum computing systems. In doing so, it would create entangled photons that remain connected on a quantum level even when far apart. This type of experiment would otherwise typically require large expensive and precisely polished crystals and is much less accessible with current technologies.
"With our results, we are excited to look at the new science that's achievable now, but also trying to push the limits of what's possible," Lawrence explained.