The photothermal effect and photodynamic effect are the main factors causing the damage of materials when laser irradiates on it. Therefore, the damage effect of laser irradiation on optical lens evaluated by thermal and mechanical effects will contribute to the development of laser processing and laser damage. In order to study the damage effect of femtosecond laser irradiating on typical K9 optical lens, real‐time temperature during irradiation was measured by infrared thermal imaging combined with laser loading system, at the same time, high‐speed camera observed the irradiation process. Then, with the help of known parameters, the stress at the moment of laser loading was calculated. Finally, the optical lens target was placed under a scanning electron microscope for observation. The results show that maximum temperature and peak stress in experiments were lower than the damage threshold of optical lenses. With the increase of pulse repetition rate, the thermal damage has a cumulative effect, while the photo‐induced pressure only increases slightly. It leads to the dominance of mechanical damage in low‐frequency pulse irradiation, whereas in high‐frequency pulse irradiation, the opposite rule occurs. For transparent materials, the laser pulse shows a stronger damage effect, the product spatters in the direction opposite to the incident beam, while the plasma discharge damage product spatters in the opposite direction, so the damage occurs on both front and back surfaces of the material at the same time.

中文翻译：

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飞秒激光辐照K9光学透镜热力学损伤效应的实验研究

当激光照射材料时，光热效应和光动力效应是导致材料损坏的主要因素。因此，通过热效应和机械效应来评价激光辐照对光学透镜的损伤效应将有助于激光加工和激光损伤的发展。为了研究飞秒激光对典型的K9光学透镜的伤害效果，结合红外热像仪结合激光加载系统，测量了飞秒激光在照射过程中的实时温度，同时用高速相机观察了照射过程。然后，借助已知参数，计算出激光加载时的应力。最后，将光学透镜靶置于扫描电子显微镜下进行观察。结果表明，实验中的最高温度和峰值应力均低于光学镜片的损伤阈值。随着脉冲重复频率的增加，热损伤具有累积效应，而光诱导压力仅略有增加。它导致在低频脉冲辐照中机械损伤占优势，而在高频脉冲辐照中则发生相反的规律。对于透明材料，激光脉冲显示出更强的破坏效果，产品在与入射光束相反的方向上飞溅，而等离子体放电损坏的产品在相反的方向上飞溅，因此损坏发生在材料的正面和背面同时。热损伤具有累积效应，而光诱导压力仅略有增加。它导致在低频脉冲辐照中机械损伤占优势，而在高频脉冲辐照中则出现相反的规律。对于透明材料，激光脉冲显示出更强的破坏效果，产品在与入射光束相反的方向上飞溅，而等离子体放电损坏的产品在相反的方向上飞溅，因此损坏发生在材料的正面和背面同时。热损伤具有累积效应，而光诱导压力仅略有增加。它导致在低频脉冲辐照中机械损伤占优势，而在高频脉冲辐照中则出现相反的规律。对于透明材料，激光脉冲显示出更强的破坏效果，产品在与入射光束相反的方向上飞溅，而等离子体放电损坏的产品在相反的方向上飞溅，因此损坏发生在材料的正面和背面同时。