Engineers out of the University of Wisconsin (Madison) have announced the creation of a nanoscale device capable of producing light as powerful as that produced by objects 10,000 times its size.
This technology drastically outpaces others before it when it comes to its ability to scatter light. Zongfu Yu, an assistant professor of electrical and computer engineering at UW-Madison who published a paper along with a team of his colleagues in the journal Physics Review Letters, proved that a single nanoresonator is able to manipulate light in such a way that it can cast a very large “reflection”.
Specifically, the nanoresonator’s capability for emitting light energy is such that it can make itself appear approximately 10,000 times as large as its physical size.
Yu and his team of came upon this discovery thanks to recent advancements made in materials innovation, and their combined understanding of the physics of light. To the latter point, the group explains that light, similar to sound, can resonate, amplifying itself as the environment around it manipulates the physical properties of its wave energy. They sought to take advantage of this property by creating an artificial material in which the wavelength of light is larger than if it were placed in a vacuum (which allows light waves to resonate more powerfully). The device they wound up creating condenses light to a size smaller than its wavelength. Doing this allows it to gather a lot of the light’s energy, which it then scatters over a very large area.
As far as real world application, this method of optical output could prove useful for imaging applications that make microscopic particles appear much, much larger.
Worth noting is that this device also possesses the unique ability to receive light energy from all directions, yielding a surprisingly strong output. This gives it several advantages over today’s lenses, whose light-gathering capacity is limited by direction and size.
“We are developing photodetectors based on this technology, and, for example, it could be helpful for photographers wanting to shoot better quality pictures in weak light conditions,” Yu explains.
In addition to improving photo-based technologies, the device could also see potential application in harvesting the sun’s energy, what with its high efficiency in terms of light absorption. To this point, Yu says he also envisions using the resonator to emit the sun’s energy as infrared light toward the sky. He explained that because the nanoresonator has a large optical cross-section (that is, its ability to emit light much larger than its physical size), it can rid itself of a lot of heat energy, making for a highly efficient passive cooling system.
“This research opens up a new way to manipulate the flow of light, and could enable new technologies in light sensing and solar energy conversion,” he says.
Read the group’s published report, “Extraordinarily Large Optical Cross Section for Localized Single Nanoresonator” for more information.
Via the University of Wisconsin-Madison
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