Fractional CO2 laser is the best laser to treat wrinkles, marks, scars, stretch marks or for facial rejuvenation or décolleté rejuvenation. The fractional CO2 laser emits tiny beams of light that penetrate the skin down to the dermis in the form of hundreds of thermal columns. These columns are small microscopic wounds that are surrounded by healthy tissue, which is the tissue that contains keratinocytes, the cells capable of promoting rapid healing and high collagen production.