Ruby laser weaknesses in the lining. Ruby lasers were used extensively in tattoo and hair removal, but are being replaced by alexandrite and s in this application. The ruby laser was the first laser to be made functional. Built by Theodore Maiman in 1960, the device was created out of the concept of an "optical maser," a maser that could operate in the visual or infrared regions of the spectrum. In 1958, after the inventor of the maser, Charles Townes, and his colleague, Arthur Schawlow, published an article in the "Physical Review" regarding the idea of optical masers, the race to build
Laser pumping is common in gas lasers. For example, in the helium–neon laser the electrons from the discharge collide with the helium atoms, exciting them. The excited helium atoms then collide with neon atoms, transferring energy. This allows an inverse population of neon atoms to build up. Electric current is typically used to pump laser diodes and semiconductor crystal lasers (for example germanium) Electron beams pump free electron lasers and some excimer lasers. Gas dynamic lasers are constructed using the supersonic flow of gases, such as carbon dioxide, to excite the molecules past threshold. The gas is pressurized and then heated to