The word Laser stands for "Light Amplification by Stimulated Emission of Radiationb"
They work of the principle of "Selective Photothermolysis" where light of a specific wavelength is selectively absorbed by a specific target called as chromophore, which is heated, damaged and eliminated, leaving surrounding skin unaffected.
1. DIODE laser (808nm) targets the chromophore (MELANIN) of the hair follicle, hence when used on the skin, it works effectively in permanent hair reduction without damaging the surface skin.
It works best on thick, black hairs while white hairs are unaffected.
2. For Qs- Nd-YaG laser, melanin in skin or tattoo ink acts as chromophore
We can use same laser for carbon peel/carbon photofacial that gives excellent glow with no downtime.