Fig. 1. (a) Structure of the gas cooled laser amplifier; (b) three-dimension view of the Nd∶glass slab

Fig. 2. (a) Temperature distribution of the Nd∶glass slab; (b) radial temperature distribution of the Nd∶glass slab center under different edge temperatures

Fig. 3. Thermal wavefront distortion of the Nd∶glass slab (a) under normal temperature and (b)at the edge temperature of 80 ℃

Fig. 4. Experimental setup of the thermal wavefront distortion measurement in the gas cooled Nd∶glass amplifier

Fig. 5. Structure of the edge heating vane

Fig. 6. Total static wavefront variation within 180 s

Fig. 7. Pump light spot distribution

Fig. 8. Wavefront distortion of the Nd∶glass with edge temperature of 70 ℃ without pumping. (a) Two-dimension; (b) three-dimension

Fig. 9. Wavefront distortion of the Nd∶glass with heat deposition of 0.6 W/cm3 without edge heating. (a) Two-dimension; (b) three-dimension

Fig. 10. Wavefront distortion of the Nd∶glass with heat deposition of 0.6 W/cm3 (a) under different edge heating temperatures and (b) at the edge heating temperature of 90 ℃

Fig. 11. Wavefront distortion of the Nd∶glass slab when the edge heating temperature is 110 ℃. (a) Two-dimension; (b) three-dimension