The term "laser" is an acronym for Light Amplification by the Stimulated Emission of Radiation. Two different lasers are used on facial skin: ablative and non-ablative. The former uses a burst of light to heat up the water in the most superficial layers of the skin, which makes the water and tissue vaporize. By being able to control exactly what level the laser penetrates down to, the administrator can create the foundation for the skin to generate a new layer of collagen as it heals, helping to reduce the appearance of wrinkles, spots and scars. Ablative lasers were originally carbon dioxide, but the new types are erbium: YAG lasers.
Non-ablative lasers were recently introduced as a safer and less invasive alternative to ablative lasers. There is less risk or downtime with this variety, which tries to treat deeper layers of tissue while leaving the top layer intact. New types of non-ablative lasers are always being developed for cosmetic use, including IPL (Intense Pulsed Light, the type used for hair removal), LHE (Light Heat Energy), Thermage, and LED (Light Emitting Diode).
An August 2008 study by the Laser & Skin Surgery Center of New York published in Lasers In Surgery And Medicine studied the effectiveness of Ablative Fractional Resurfacing (AFR), which uses an erbium laser to create tiny wounds in the skin. They found that AFR is promising as a middle ground between the two types of lasers, offering more dramatic results with less side effects than traditional ablative lasers.