Which characteristic distinguishes IPL from a laser?

• A. Coherent light
• B. Monochromatic light
• C. Non-coherent, broadband light
• D. Single-mode energy delivery

Answer: (C)

The way the light is produced—its coherence and spectral content—drives how IPL differs from a laser. IPL emits non-coherent, broadband light, meaning the photons are not phase-locked and come across a wide range of wavelengths. Filters can shape the spectrum, but the output remains broad compared with a laser, which limits spectral precision. This broad, multi-wavelength delivery is useful for targeting multiple chromophores and skin conditions, but it lacks the crisp wavelength control a laser provides. A laser, on the other hand, emits coherent light that is nearly monochromatic with a narrow spectral width, producing a highly focused, single-wavelength beam with strong spatial and temporal coherence. That combination enables selective photothermolysis with precise wavelength targeting.

So, the characteristic that distinguishes IPL from a laser is the non-coherent, broadband nature of IPL light.