Fig. 1. Schematic diagram of the non-evaporative laser repairing of fused silica surface damage. (a) CO2 laser repairing schematic; (b) original surface damage pit.

Fig. 2. Surface morphology evolutions and phase transition processes of fused silica optics irradiated by CO2 lasers with different powers. (a), (c), (e) represent the heating stage at the laser action time of 5 s; (b), (d), (f) are the cases when cooling is for 0.1 s. In the pseudo-color scale, one represents the liquid phase, while zero represents the solid phase.

Fig. 3. CO2 laser repairing experiments of different laser powers and corresponding calculated morphologies under the same condition.

Fig. 4. Evolution process of crack morphology under laser action.

Fig. 5. Size of the residual air layer inside the crack irradiated by the laser of different powers.

Fig. 6. Repairing results of two processing schemes. (a) and (d) are the initial surface damage morphologies; (b) and (c) are the repairing results of scheme I; (e) and (f) are the repairing results of scheme II.