Smuggling light through opaque materials

Electrical engineers have discovered that changing the physical shape of a class of materials commonly used in electronics can extend their use into the visible and ultraviolet parts of the electromagnetic spectrum. Already commercially used in detectors, lenses and optical fibers, chalcogenide glasses may now find a home in applications such as underwater communications, environmental monitoring and biological imaging.

from Latest Science News -- ScienceDaily https://www.sciencedaily.com/releases/2021/10/211005124739.htm