History of LASER

LASER is the short form of light amplification by stimulated emission of radiation. LASER is a highly coherent, highly monochromatic, high intensity unidirectional source of light. Ruby laser was the first fabricated laser. Maiman operated it for the first time. Later Sorokin and Stevenson fabricated Uranium-calcium fluoride laser. In 1961, Neodymium: glass laser was fabricated by Snitzer and Neodymium: CaWO4 laser by Johnson. After 4 years, Johnson and team succeeded in the fabrication of Neodymium:YAG laser and Holmium: YAG laser. The working of Holmium laser is based on the cascade energy transfer phenomena. This enhances lasing efficiency. Later GaAs lasers were fabricated which are quite economical, efficient, compact and portable. Now many types of laser exist in the market that cover a wide range of wavelength from ultraviolet to infrared and with wide variety of output power. The main components of a laser system are active medium, pumping unit, cavity resonator and a cooling system.