4.5 ns, 10 kHz, high-beam-quality 532 nm laser employing acousto-optic Q-switching and type-I non-critical phase matching

A high-beam-quality, narrow-nanosecond, acousto-optically (AO) Q-switched green laser system is demonstrated. The system employs a master oscillator power amplifier configuration with an extra-cavity frequency-doubling module. The master oscillator is an end-pumped AO Q-switched Nd:YVO 4 laser that generates a 1.62 W, 1064 nm seed beam at a repetition rate of 10 kHz, with a pulse duration of 5.0 ns and beam-quality factors of M x 2 = 1.231 and M y 2 = 1.221. After single-stage amplification, the output power reaches 4.38 W, with a pulse duration of 5.3 ns and beam-quality factors of M x 2 = 1.244, M y 2 = 1.229. Using a noncritically phase-matched LBO crystal for second-harmonic generation (SHG), the system produces 1.65 W of 532 nm output with a pulse duration of 4.5 ns and beam-quality factors of M x 2 = 1.095 and M y 2 = 1.131. The frequency-doubling conversion efficiency reaches 37.67%.