80-W single-frequency Innoslab µs-amplifier at 1319 nm with high efficiency

A single-frequency quasi-continuous-wave partially end-pumped slab (Innoslab) laser amplifier at 1319 nm was demonstrated. The 3-W single-frequency all-fiber seed laser was amplified to a maximum average power of 80.1 W and the power stability was 0.52% in 10 minutes. The corresponding optical-optical efficiency was 16.1% under absorbed pump power of 478 W. The output pulse width was 131 µs at the repetition of 500 Hz. The beam quality factors of M² were 1.3 in both the vertical and horizontal directions. To the best of our knowledge, this is the first report on single-frequency Nd:YAG Innoslab amplifier at 1319 nm with such high output power and efficiency.