Neodymium doped Yttrium Aluminum Garnet Nd:YAG crystal
Nd:YAG crystal, which continues as the best of the rare earth garnet materials that are characterized by four-level laser operation which permits low threshold pulse and cw operation, is the most mature and widely used solid-state laser material adopted by R&D, medical, industrial and military customers. Its main and obvious advantages are: high gain, low threshold, high efficiency, low loss at 1.064 nm, as well as high optical quality, good thermal conductivity and thermal shock characteristics, stable chemical and mechanical properties, which make Nd:YAG as the most suitable and commercial laser material for various modes of operation (CW, pulsed, Q-switched, mode locked and cavity dumped).
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Ytterbium doped Yttrium Aluminum Garnet Yb:YAG crystal
Yb:YAG is one of the most promising laser-active materials and more suitable for diode-pumping than the traditional Nd-doped crystals. It can be pumped at 0.94 nm and generates 1.03 nm laser output. Compared with the commonly used Nd:YAG crystal, Yb:YAG crystal has a larger absorption bandwidth in order to reduce thermal management requirements for diode lasers, a longer upper-state lifetime, three to four times lower thermal loading per unit pump power. Yb:YAG crystal is expected to replace Nd: YAG crystal for high power diode-pumped lasers and other potential applications, such as, its doubling wavelength is 515 nm very close to that of Ar-ion laser (514 nm),which makes it possible to replace large volume Ar-ion laser.
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