Due to their high intensity and relative brightness at short wavelengths (extending into the ultraviolet) and short pulse widths, flashtubes are also ideally suited as light sources for pumping atoms in a laser to excited states where they can be stimulated to emit coherent, monochromatic light. Proper selection of both the filler gas and current density is crucial, so that the maximum radiated output-energy is concentrated in the bands that are the best absorbed by the lasing medium; e.g. krypton flashtubes are more suitable than xenon flashtubes for pumping , as krypton emission in near infrared is better matched to the absorption spectrum of Nd:YAG.