Kilowatt-level 100 kHz nanosecond pulsed laser amplifier via a 205-watt seeding

Nanosecond (ns) pulsed laser with high average power and high pulse repetition rate above 50 kHz is a potential solution for laser cutting, laser welding, laser cleaning and many other industry processing scenarios. Although Nd:YAG is a widely used solid-state gain medium, it is difficult to obtain ns pulsed laser with repetition rate above 50 kHz due to its limited stimulated emission cross section and thermal distortion under high pump intensity. In this paper, a kilowatt-level 100 kHz high repetition rate ns Nd:YAG master oscillator power amplifier (MOPA) laser system is reported, and a general optimization method was used to obtain a 205 W seed laser with a high repetition rate of 100 kHz. After beam shaping elements, the seed laser was amplified to 1008 W by a two-rod Nd:YAG preamplifier and a two-rod Nd:YAG main amplifier. The pulse-to-pulse stability factor of the pulsed laser was 0.961 and the pulse width was measured as 142.8 ns. The beam parameter product in the horizontal axis and vertical axis were measured as BPPx = 2.81 mm∙mrad and BPPy = 2.78 mm∙mrad respectively. This is the first time to obtain a kilowatt-level average power ns pulsed laser with repetition rate above 50 kHz using Nd:YAG, and the compact MOPA system is also suitable for power scaling and other practical use.