UV light, or ultraviolet radiation, is electromagnetic energy just beyond the visible spectrum. It is strong enough to trigger chemical and physical changes in some materials, especially dyes, polymers, coatings, and light-sensitive semiconductor films. In the article context, UV light matters because it can act as a control input rather than just background illumination: exposure can change a material’s state, not merely reveal it.
In cyber security, that matters for both attack surface and defense. A defender may use UV-reactive inks, tags, or markers for authentication, anti-counterfeiting, or tamper evidence. An attacker, or an untrusted environment, might use UV exposure to alter or erase those markers, or to influence components that were assumed to be stable after fabrication. Security reviews should therefore consider light sensitivity, exposure history, and whether a device or package contains materials that can be changed by UV wavelengths.