Applications of Nd: YAG Lasers in material processing: Fundamental approach

Lasers are devices that produce intense beams of light which are monochromatic, coherent and highly collimated. The wavelength of laser light is extremely pure when compared to other sources of light and all of the photons that make up the laser beam have a fixed phase relationship with respect to one another. Among solid state lasers, Nd: YAG laser has an important role due to its high efficiency, possibility to tune it in different wavelengths from infrared till ultraviolet and change pulse duration from milliseconds down to picoseconds. Nd: YAG lasers can operate in both pulsed and continuous mode providing power outputs between 0.04-6000 W. Solid-state lasers operate at very low wavelengths and hence cannot be operated with the naked eye. Nd: YAG is usually used in monocrystalline form, fabricated with the Czochralski growth method, but there is also ceramic Nd: YAG available in high quality and in large sizes. For both monocrystalline and ceramic Nd: YAG, absorption and scattering losses within the length of a laser crystal are normally negligible, even for relatively long crystals. One of the prime advantages of the Nd: YAG laser over the CO2 laser is the ability to deliver laser radiation through optical fibers. This paper deals with the detailed properties and applications of Nd: YAG lasers in material processing.