The excimer lasers are a group of lasers that have found wide application in a variety of medical fields including dermatology, cardiology, ophthalmology, and orthopedics. The word excimer refers to excited dimer. These lasers operate in the ultraviolet range, and examples include the 193 nm argon-fluroide, 248 nm krypton-fluoride, 351 nm xenon-fluoride, and of particular interest to dermatology, the 308 nm xenon-chloride. These lasers utilize a mixture of a noble gas and a halogen as a lasing material. They were first used in medicine for their ability to produce cold tissue ablation, but more recently have been used in dermatology as a method of non-ablative phototherapy.