What is a broadband light source?

In contrast to the very narrow-band monochromatic light sources, whose intensity distribution resembles a narrow tip, broadband light sources deliver polychromatic light over a greater wavelength range.

In a natural environment, intensity distributions of this type arise, for example, in gas clouds from the superposition of many narrow-band emissions, e.g. in molecular spectrums. Depending on the light source, intensity reductions are also possible within the broadband range. This must be avoided in technical applications.

Examples of broadband light sources are thermal light sources (halogen lamps, xenon gas discharge lamps, and laser-pumped plasma light sources), or light sources based on fluorescence (laser-pumped white light sources, white light LEDs). A monochromator can be used to isolate a freely selectable, narrower wavelength range from the emission of broadband light sources.