Sapphire fiber could enable cleaner energy and air-travel

https://phys.org/news/2022-04-sapphire-fiber-enable-cleaner-energy.html

"uses a sapphire optical fiber—a thread of industrially grown sapphire less than half a millimeter thick... can withstand temperatures over 2000°C. When light is injected onto one end of the sapphire fiber, some is reflected back from a point along the fiber which has been modified to be sensitive to temperature... writing a channel along length of fiber, such that light is contained within tiny cross-section, one-hundredth of a millimeter in diameter"