The reason why xenon lamps are used in fluorescence spectroscopy is because xenon lamps have extremely high brightness and stability, and can generate high-energy ultraviolet rays to excite sample molecules, thereby exciting them to fluoresce. In this issue, we will describe the light source, an important part of the spectrophotometer that was explained in "The Structure of a Spectrophotometer" in UV Talk Letter Vol. Light Source. Still today, Agilent remains the technology leader and provides innovative workflow solutions using xenon lamps in the Cary 60 UV-Vis, Cary 3500 UV-Vis, and Cary Eclipse Fluorescence spectrophotometers. Schematic drawing of the Cermax spectrofluorometers. A traditional 450W lamp is about 10 cm (4. Excitation of Xenon Atoms: The electrical discharge through the xenon gas excites xenon atoms by knocking electrons to higher energy levels. When these electrons return to their original energy levels, the xenon atoms emit photons.