A diode-pumped continuous-wave Nd:YAG laser with an average output power of 1 kW

A diode-pumped Nd:YAG laser with an average output power of 1 kW is developed for industrial applications, such as metal cutting, precision welding, etc. To develop such a diode-pumped high power solid-state laser, a series of laser modules have been used in general with and without thermal birefringence compensation. For example, Akiyama et al. used three laser modules to obtain a output power of 5.4 kW CW.1 In the side-pumped Nd:YAG laser, which is a commonly used pump scheme to obtain high output power, the crystal rod has a short thermal focal length at a high input pump power, and the short thermal focal length in turn leads to beam distortion within a laser resonator. Therefore, to achieve a high output power with good stability, isotropic beam profile, and high optical efficiency, the detailed analysis of the resonator stability condition depending on both mirror distances and a crystal separation is essential