Original: Illumination and optics Gas-discharge lamps Xenon is used in light-emitting devices called xenon flash lamps, which are used in photographic flashes and stroboscopic lamps; to excite the active medium in lasers which then generate coherent light;  and, occasionally, in bactericidal lamps.
Simplified: Xenon gas is used in electron tubes, bactericidal lamps, stobe lamps, and lamps used to excite ruby lasers.