ABSTRACT
This chapter is an introduction to high power lasers and it is intended to present the principles and the parameters of such systems. Lasers (acronym of light amplification by stimulated emission of radiation) are devices that generate or amplify electromagnetic radiation, ranging from the long infrared region up through the visible region and extending to the ultraviolet and recently even to the x-ray region (Ross 1968, Sargent et al. 1974, Svelto 1976, Thyagarajan and Ghatak 1981, Siegman 1986, Elton 1990, Diels and Rudolph 1996 and Robieux 2000). The 1964 Nobel Prize for physics was shared between Charles Townes, Nikolai Basov and Alexander Prokhorov for their fundamental work in the 1950s that led to the construction of the laser.
