Physicists have spent more than a century measuring and making sense of the strange ways that photons, electrons, and other subatomic particles interact at extremely small scales. Engineers have spent decades figuring out how to take advantage of these phenomena to create new technologies.
In one such phenomenon, called quantum entanglement, pairs of photons become interconnected in such a way that the state of one photon instantly changes to match the state of its paired photon, no matter how far apart they are.
Nearly 80 years ago, Albert Einstein referred to this phenomenon as "spooky action at a distance." Today, entanglement is the subject of research programs across the world—and it's becoming a favored way to implement the most fundamental form of quantum information, the qubit.
Currently, the most efficient way to create photon pairs requires sending lightwaves through a crystal large enough to see without a microscope.
In a paper published in Nature Photonics, a team led by Columbia Engineering researchers and collaborators describe a new method for creating these photon pairs that achieves higher performance on a much smaller device using less energy. P. James Schuck, associate professor of mechanical engineering at Columbia Engineering, helped lead the research team.
These findings represent a significant step forward in the field of nonlinear optics, which is concerned with using technologies to change the properties of light for applications including lasers, telecommunications, and laboratory equipment.
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