The principle behind hair removal is selective photo thermolysis (heat is being
absorbed by melanin, which eventually heats up the hair shaft, the hair follicle, the
surrounding area and the germinating layers in such a way that the melanin helps
in destroying the hair. The chromophore here is melanin, which is competing with
other chromophores that are oxyhemoglobin and water [1,5]. The spectrum of 600
nm to 1,100 nm wavelength is useful in destroying the hair follicle, but the more
specific we are, the lesser chance of complications. This brings us down to a few
technologies utilizing different wavelength, such as Pulsed Diode, Nd-Yag,
Alexandrite,Ruby, which are a little more specific when it comes to heating the
melanin which helps in destroying the hair.
During YAG laser hair removal, a laser emits a light that is absorbed by the
pigment (melanin) in the hair. The light energy is converted to heat, which
damages the tube-shaped sacs within the skin that produce hairs; this damage
inhibits or delays future hair growth. It works well because it has a weaker melanin
absorption rate than other lasers. Melanin absorption refers to the rate at which the
laser’s heat and light are absorbed by the melanin.
