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In this paper, the damage characteristics of MgF2 window material were investigated by building a 193 nm UV excimer laser damage experimental system under different laser fluences of 193 nm excimer laser. The damage morphology was also observed by differential phase contrast microscopy (DIC). The damage mechanism of 193 nm excimer laser irradiated MgF2 window material was investigated. Finite element simulation experiments were also conducted for the defective MgF2 window material. The distribution of temperature and stress fields in the 193 nm UV laser irradiated MgF2 window material was numerically analyzed using the finite element method. The results show that when the laser irradiates the MgF2 window material, the damage threshold of the rear surface of the window material is 2.523 J/cm2 and the damage threshold of the incident surface is 9.74 J/cm2, that is, the rear surface is damaged before the incident surface. At the same time, the rear surface damage profile increased catastrophically with the growth of irradiated laser energy, while the incident surface damage profile increased linearly with the growth of irradiated laser energy. The main factor causing the damage to the window material is the damage caused by the defects contained in it, which causes stress damage to the window material during laser irradiation.
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