Laser aesthetic treatment principle Laser irradiation will produce photothermal effect, photochemical effect, pressure effect, electromagnetic field effect and biological stimulation effect on the skin tissue. The most important one is the photothermal effect. When the laser output specific wavelength irradiates the skin lesion, the light energy is converted into heat energy, which is selectively absorbed. The extremely high thermal energy causes the skin lesion tissue to be rapidly pyrolyzed, vaporized, or broken into tiny fragments, which are engulfed by phagocytes in the body and discharged out of the body, thus achieving the purpose of eliminating the skin lesion. Because the normal skin tissue around the lesion absorbs little heat energy, it will not cause any damage. The photochemical effect is to provide energy for tissue metabolism, accelerating and directly triggering biochemical reactions. The piezoelectric effect generates counter-stamping, vapor pressure, ultrasonic pressure and thermal expansion in the tissue to destroy the lesioned tissue. Electromagnetic effect generates electromagnetic waves to denature and destroy proteins in diseased tissues. Biostimulation effect can promote tissue repair, cell regeneration, improve the body’s immunity, while sterilization and antibacterial, reduce tissue inflammation response, etc. Laser is used more and more widely in the cosmetic industry Laser is a monochromatic light with high energy, precise focus and certain penetrating power, which acts on human tissues and generates high heat locally to remove or destroy target tissues, and various pulsed lasers with different wavelengths can treat various vascular skin diseases and pigmentation, such as nevus of Ota, nevus of vivid redness, freckles, age spots, capillary dilation, etc., as well as Tattoo removal, eyeliner cleaning, eyebrow cleaning, treatment of scarring, etc.; and in recent years, some new lasers, high-energy ultra-pulse CO2 laser, erbium laser for wrinkle removal, skin resurfacing, snoring treatment, teeth whitening, etc., have achieved good results, opening up an increasingly broad field for laser surgery. And in recent years, with the emergence of different wavelength lasers, high-energy ultra-pulsed CO2 lasers, variable pulse lasers and erbium lasers, etc., laser cosmetology has set off a climax in the medical cosmetic industry. The use of laser in the cosmetic world is becoming more and more extensive. Classification of laser cosmetic 1, laser according to its medium can be divided into: ① solid laser; ② gas laser; ③ liquid laser; ④ semiconductor laser. The introduction of cosmetic lasers has provided a new technical treatment for the field of cosmetic surgery, and also solved many problems that could not be solved by previous treatment methods. However, most cosmetic laser equipment has only entered our medical industry in recent years due to its technical precision and high price. Lasers achieve their function by interacting with tissues. According to what kind of energy the tissue converts the laser into, the laser is divided into; ① photothermal effect: the tissue converts the light energy of the laser into heat energy, different tissues have different absorption coefficients, so a specific wavelength of laser can be absorbed by some specific tissues, which is the fundamental reason for the high choice of laser, such as laser fine cutting, hemostasis and facial wrinkle removal; ② light burst effect: pulsed laser can produce a high-impact shock wave that can burst and shatter tissue, such as laser destruction of pigment particles, etc.; ③ photochemical effect; the tissue converts the laser into chemical energy, resulting in chemical decomposition. Such as ArF excimer laser correction of corneal deformation; ④ photodynamic effect: mainly used for the treatment of tumors. 2, laser beauty can be divided according to the use of: (1) laser removal of facial skin pigments, such as melanin (moles and tattoos), red pigment (hemangioma); (2) laser removal of moles, warts, papules, redundant, benign tumors and other skin defects; (3) laser permanent removal of excess body hair; (4) laser removal of facial wrinkles; (5) laser knife instead of scalpel to carry out fine, minimally invasive, bloodless plastic surgery.