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强激光辐照锗材料可造成材料的破坏。对波段外脉冲激光辐照锗材料进行了理论研究,建立了激光辐照锗材料的热力耦合数学物理模型,对热传导方程和应力平衡方程进行有限元数值求解,对不同能量密度下波段外激光辐照锗材料的瞬态温度场和应力场分布进行了数值模拟计算,得到了材料最易损伤的位置和材料的损伤阈值以及锗材料的损伤阈值与激光参数之间的关系。分析结果表明:热应力损伤在锗材料的脉冲强激光损伤中占据主导地位,锗材料出现热应力损伤的激光能量密度小于出现熔融损伤的激光能量密度,应力损伤主要集中在光斑中心区域并体现为压应力损伤。
Strong laser irradiation of germanium materials can cause material damage. A theoretical study on the pulsed laser irradiation of germanium was carried out. A thermodynamic coupling mathematical model of germanium irradiated by laser was established. The thermal conductivity equation and stress equilibrium equation were solved by finite element method. According to the transient temperature field and stress field distribution of germanium material, the damage threshold of the material and the damage threshold of the material are obtained, and the relationship between the damage threshold of the germanium material and the laser parameters is obtained. The results show that thermal stress damage plays a dominant role in the pulsed laser damage of germanium material. The laser energy density of thermal stress damage of germanium material is smaller than the laser energy density of melt damage. The stress damage mainly concentrates in the central region of the spot Compressive stress damage.