A laser is a light beam that can be focused on a very small area. The laser heats cells in the area being treated until they "burst". There are several types of lasers. Each laser has specific uses. The color of the light beam used is directly related to the type of surgery being performed and the color of the tissue being treated. Types of lasers include the carbon dioxide (CO2) laser, the YAG (yttrium aluminum garnet) laser, alexandrite, KTP, and the pulsed dye laser.