Abstract
With the invention of large-mode-area fiber and cladding pump technique, output power of rare-earth doped fiber lasers were significantly enhanced in recent years. Fiber-based systems have many attractive features such as constant beam quality independent of laser power, high optical efficiency, and easy heat removal. However, “bulk solid-state-laser” is still a choice of geometry in high-pulse-energy regime. Scaling of pulse energy with a fiber-based system is limited mainly due to damage threshold, nonlinear effect, and energy dissipation induced by parasitic lasing. To overcome these issues, we selected a combination of a Nd: YAG laser oscillator and a large-core fiber amplifier. The system producing 24m J pulse energy with repetition rate of 2k Hz was demonstrated. The pulse energy is, to our knowledge, the highest number obtained at more than 1k Hz range.
