How do hair removal lasers differentiate between hair and skin?

The correct answer emphasizes that hair removal lasers specifically target the pigment in the hair follicles. The mechanism relies on the principle of selective photothermolysis, where the laser targets areas with more pigmentation. Hair contains a higher concentration of melanin compared to the surrounding skin, which allows the laser to effectively differentiate between hair and skin.

When the laser beam is emitted, it penetrates the skin and is absorbed primarily by the melanin in the hair follicle. This absorption leads to the destruction of the hair follicle while minimizing damage to the surrounding skin, which has less pigment. This targeted approach ensures that the treatment is both effective in reducing hair growth and safe for the skin.

Other methods or indicators such as tactile feedback do not apply to the operation of laser hair removal. Furthermore, lasers do not function uniformly across both skin and hair, and they cannot entirely ignore skin since lasers must interact with it to reach the hair follicles. Understanding this targeting mechanism is crucial for effective and safe laser hair removal practices.