Fig. 1. Schematic diagram of the layout of the reflecting mirrors

Fig. 2. Schematic diagram of the four types of support methods (constraints). (a) 1# support method; (b) 2# support method; (c) 3# support method (d) 4# support method

Fig. 3. Schematic diagram of the local coordinates and three sufaces of the reflecting mirror

Fig. 4. Temperature distribution of the reflecting surface (P=1500 W, t=5 s)

Fig. 5. Mirror deformation and introduction of optical path difference. (a) Deformation of the reflecting mirror; (b) optical path difference introduced by the deformation

Fig. 6. Distribution of introduced optical path difference (Δ_OPL) caused by the relative deformation of the reflecting surface in the beam spot area under 1#‒4# support methods and their comparison. (a) 1# support method; (b) 2# support method; (c) 3# support method; (d) 4# support method; (e) comparison of Δ_OPL distribution in the spot area under 1#‒4# support methods

Fig. 7. Errors between the original wavefront phase plane and the reconstructed phase plane, original phase plane and reconstructed phase plane for different support methods. (a) 1# support method; (b) 2# support method; (c) 3# support method; (d) 4# support method

Fig. 8. Deformation distribution of the mirror surface in spot area measured by Hartmann

Fig. 9. Maximum value of mirror surface's relative deformation with the laser raying time