Lasers were used for medical applications almost as soon as they were discovered in the 1960s. Since sunlight had been widely used for medical treatment for centuries in dermatology and, in the twentieth century, in ophthalmology, lasers were quickly applied with great success in the early 1960s for the treatment of skin diseases. It was noted that skin pigments were selectively destroyed with minimum white skin damage [1]. Tumor removal was attempted soon after, where much reduced bleeding was observed due to cauterization of blood vessels [2]. Medical applications of lasers have closely followed the development of lasers during the past 60 years. Many different medical applications of lasers have emerged. It is now hard to nd a single area of medicine that is not touched by lasers. Depending on the nature of the application, very different requirements are often placed on lasers. A medical system is often designed for a very specic application.