Power/Performance Bits: April 20
Multiplexing twisted light; flexible body heat harvesting; carbon quantum dots.
Multiplexing twisted light
Researchers from University of California San Diego and University of California Berkeley found a way to multiplex light by using discrete twisting laser beams from antennas made up of concentric rings.
“It’s the first time that lasers producing twisted light have been directly multiplexed,” said Boubacar Kanté, an Associate Professor at UC Berkeley’s Department of Electrical Engineering and Computer Sciences. “We’ve been experiencing an explosion of data in our world, and the communication channels we have now will soon be insufficient for what we need. The technology we are reporting overcomes current data capacity limits through a characteristic of light called the orbital angular momentum. It is a game-changer with applications in biological imaging, quantum cryptography, high-capacity communications and sensors.”
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Quantum dots generally refer to specially fabricated nanocrystals that exhibit unique electrical and optical properties due to their inherent quantum properties. However, conventional technology has limited quantum dots to toxic and costly metals as raw materials.
A new study has found a cheaper, safer alternative material that could be further purified to replace toxic metal quantum dots with the same efficiency in various applications.
While there have been prior studies on finding non-toxic and more cost-effective alternatives, these proposed quantum dots emit less light when exposed to ultraviolet (UV) light. In the new study, titled Ultrafast nanometric imaging of energy flow within and between single carbon dots and published in the National Academy of Sciences latest Proceedings, researchers detail how ultrafast nanometric imaging has revealed clusters of good and bad emitters in entire populations of carbon dots. Researchers suggest that by selecting only the good
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IMAGE: Martin Gruebele, right, and graduate student Huy Nguyen demonstrate that economical carbon-based quantum dots emit enough light when excited to eventually replace the expensive and toxic metal quantum dots used. view more
Credit: Photo by L. Brian Stauffer
CHAMPAIGN, Ill. Tiny fluorescent semiconductor dots, called quantum dots, are useful in a variety of health and electronic technologies but are made of toxic, expensive metals. Nontoxic and economic carbon-based dots are easy to produce, but they emit less light. A new study that uses ultrafast nanometric imaging found good and bad emitters among populations of carbon dots. This observation suggests that by selecting only super-emitters, carbon nanodots can be purified to replace toxic metal quantum dots in many applications, the researchers said.