Photonic device makes light any color by manipulating individual photons

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2. From the linked article.

The team says that this powerful new tool could have a range of applications in the field of photonics, including communications, quantum computing and AI, and its design should allow for more compact devices.

“It’s very versatile,” says Shanhui Fan, senior author of the study. “The engineer can control the frequencies and proportions very accurately and a wide variety of transformations are possible. It puts new power in the engineer’s hands. How they will use it is up to them.”

It has a range of applications.