Fig. 1. Schematic of the experimental setup.

Fig. 2. Pump and cooling architecture of the amplifier.

Fig. 3. Output characteristics of the oscillator versus pump energy in the QCW and Q-switched modes.

Fig. 4. Optical spectrum of the Nd:YLF master oscillator.

Fig. 5. Output energies at the pre-amplifier during single-pass and double-pass amplification.

Fig. 6. Output energy after the amplifier as a function of pump energy and the simulation based on the F–N equation.

Fig. 7. Temporal trace of laser pulse: (a) pulse from the oscillator; (b) pulse from the amplifier.

Fig. 8. Beam quality measurement of the MOPA system (50 Hz, 655 mJ pulse energy).

Fig. 9. Far-field beam intensity distribution after amplification.