By Dan Zehr
AUSTIN, Texas (AP) – Researchers can envision a minuscule machine that generates pristine images of the smallest living molecules.
They can imagine a computer chip that runs thousands of times faster than current incarnations, yet remains cool enough to use in a laptop computer.
Those products remain many years and several discoveries into the future, but a collaboration of researchers at the University of Texas at Austin and Taiwan’s National Tsing Hua University have recently moved a step closer.
In late July, the group announced the creation of the world’s smallest semiconductor-based nanolaser. The device is 500 nanometers long and 60 nanometers wide and high at its thickest points. By comparison, the width of a fine human hair is about 50,000 nanometers.
Such tiny lasers could eventually become crucial building blocks in a range of advanced optical, medical and computer technologies. For example, they could become the foundational component of a new breed of computer chips that would transmit information via pulses of light instead of electrons, thus overcoming the speed, density and heat barriers that limit performance today.
However, creating a functional laser that small presents considerable challenges. At sizes smaller than the wavelength of light, it becomes increasingly difficult for a laser to contain enough of its own photons to sustain a continuous operation.
UT physics professor Chih-Kang “Ken” Shih and Charlotte Sanders, a graduate student on his team, constructed an exceptionally smooth silver film that helps limit the loss of energy while simultaneously tightening the field of laser-generating activity.
Shih has worked on perfecting these types of advanced materials for more than 15 years. He and Sanders created the silver film at their lab in Austin, and the nanolaser was built and tested by one of Shih’s former graduate students and his colleagues at the Taiwanese university.
“The main innovation is the kind of silver that they created,” said Yeshaiahu “Shaya” Fainman, a University of California, San Diego electrical and computer engineering professor who has worked extensively on nanolasers but wasn’t part of this project.
Past films used in this type of nanolaser contained gaps between the tiny atomic-scale clumps of metal, Shih and Sanders said. Those gaps and clumps would scatter the useful wave of energy researchers ultimately wanted to produce – a photon-electron hybrid called surface plasmon polariton.1 2 next >>
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