The carbon dioxide(CO2) laser is used to treat various skin lesions that are not flat (such as keloid scars or warts). It can be used to smooth out the skin or for cutting the skin and removing tissue. The laser emits a beam of light, which is absorbed causing heat damage to the skin cells and destroying them. If the beam is focused, it will cut the skin and seal any bleeding vessels. If the beam is defocused, the effect is scattered over a wider area and results in vaporisation of a thin layer of skin cells.