Fig. 1. Layout of the LD-pumped gas-cooled multislab Nd:glass amplifier. LD1–LD2: laser diode arrays; L1–L6: lenses; MON: monitor; 10X: expander; SA: serrated aperture; PBS: polarization beam splitter; FR: Faraday rotator; M1–M4: 1053-nm HR mirrors; DM5–DM6: dichroic mirrors.

Fig. 2. Schematic overview of the amplifier head.

Fig. 3. Sketch overview of the fringe mirror.

Fig. 4. Pump light distribution: (a) experimental result; (b) theoretical prediction.

Fig. 5. Pump profiles at different positions.

Fig. 6. Gain distribution over the cross section of the four slabs.

Fig. 7. Single-pass, thermally induced transmitted wavefront distortion through the amplifier: (a) theoretical prediction; (b) experimental result.

Fig. 8. 2D-Legendre polynomial analysis of the measured single-pass transmission wavefronts.

Fig. 9. Wavefront aberration profile with the defocus term removed.

Fig. 10. Predicted and measured output energy of the amplifier as a function of the number of passes at different repetition rates for a pump pulse energy of 7.3 J. The inset shows the near-field profile of the output for a repetition rate of 0.2 Hz at a 0.5 J operation.

Fig. 11. Output energy stability at 0.2 Hz.