Professional IPLs with filter emit infrared that operates in the 800 nanometer band and is therefore invisible. These rays have a great affinity with melanin, the pigments that give hair their color.
When filtered xenon light is directed onto the skin, it is absorbed only by the hair bulbs. This accumulation of light in the bulbs will cause intense heat, which can rise for a short time to 75°. This leads to destruction of the hair caused by the destruction of its deep roots.
Indeed the heat produced by the laser results in multiple micro coagulations at the base of the hair at the level where the cells ensure its renewal.