Laser hair removal is based on the principle of selective photothermodynamics. By reasonably adjusting the wavelength, energy and pulse width of the laser, the laser can pass through the surface of the skin and reach the hair follicle at the root of the hair. The light energy is absorbed and converted into damage to the hair follicle tissue. Heat energy, so that the hair loses its ability to regenerate, and at the same time does not damage the surrounding tissue, and the pain is mild. In addition, laser hair removal takes advantage of the "selective photothermal effect" of lasers, using lasers tuned to specific wavelengths to pass through the epidermis and directly irradiate the hair follicles. The melanin in the hair follicle and hair shaft selectively absorbs light energy, and the resulting thermal effect causes the hair follicle to necrosis, and the hair no longer grows. The effect of laser hair removal, because the process of endothermic necrosis of hair…