Lasers seem to be used for everything nowadays - from 3D carvings to acne removal.
In order to understand how laser works on skin, hair and acne, it is first necessary to understand what laser is, in the first place. LASER isn't really a word - it's an acronym, just like UNICEF or UNESCO. Its full form is "Light Amplification by Stimulated Emission of Radiation". As the definition/full form itself says, laser beams are produced by amplifying light waves, I.e. Increasing their amplitude. This amplification is done by passing light waves repeatedly into a medium which causes the waves to rise in amplitude. The medium is called a "gain medium", and the amplification usually uses mirrors or total reflecting prisms. The end result is that a highly focused beam of energy jets out of a cavity in one of the reflecting surfaces, and is accompanied by a relatively weaker beam of light that emerges due to the constant and repeated reflections taking place. Cosmetic laser clinics use pulsed lasers. In pulsed laser, the beams of energy are emitted in pulses rather than a single, constant and steady stream. This is useful for several reasons: It avoids burning sensitive skin It allows energy to be focused on nodes that need it, such as growing hair roots or acne itself It allows the practitioner to control the duration and intensity of the beam betterLASER appliances used in cosmetic clinics are usually tuned so that only a particular type of tissue will respond to them. In hair removal, the frequency of laser is such that melanin-heavy follicles will respond better than the surrounding, light-coloured portions. Thus, the laser beam is preferentially absorbed by the hair follicle, and its cellular structure is changed permanently by the action of the heat. This means that only people who hair is substantially darker than their skin will be suitable candidates for laser hair removal. Light blondes and redheads are by default excluded from the laser depilation clinic, while people with very dark skins may find that a higher intensity of laser is required to remove their hair. Since dark skin tends to absorb laser beams just as dark hair would do, it is quite likely that dark-skinned people will experience worse swelling as a result of laser hair removal than those with fairer skin. To remove acne, the cells targeted by the laser are haemoglobin-rich cells. The haemoglobin in the cells absorbs the laser beam, and gets heated up. This heat travels through to the sebaceous glands, which then slow down their activity dramatically. This way, acne can be minimized or prevented. By tackling the problem at its source, laser cosmetic technology can provide non-invasive, nearly painless solution for some of the most common cosmetic problems.
