Abstract The traditional method for calculating laser induced damage threshold (LIDT) value of thin films is based on qualitative or semi-quantitative empirical formulas, the results obtained are of low accuracy and credibility. A new method for accurately calculating LIDT values of thin films is presented in this paper, when a thin film is subjected to intense laser irradiation, the distribution models of internal electric field-absorption-temperature field are constructed respectively. In general, when the corresponding temperature value at a certain time and a certain depth is the maximum value in the temperature field distribution of the thin film, the incident laser energy is the damage energy threshold of the thin film at this time, and the depth is the location where the thin film is most prone to damage. Therefore, an expression of the relationship between the damage energy threshold and the maximum temperature can be established, which can be used to combine to the relation expressions of critical electron density with temperature maximum and damage energy threshold respectively, the LIDT values of the thin films can be solved simultaneously. In order to verify the reliability of the method, the LIDT values of single-layer titanium dioxide, silicon dioxide and diamond-like carbon (DLC) thin films were calculated respectively, their experimental values are obtained at the same time, and each film’s theoretical value was compared with the experimental value several times The results show that their theoretical values and experimental values are consistent, indicating that this new method for calculating LIDT of thin film is feasible, and it not only enriches and develops the traditional theoretical calculation methods, but also provides a new judgment basis for evaluating the resistance to laser damage of thin films.

中文翻译：

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一种计算薄膜激光诱导损伤阈值的新方法

摘要 传统的薄膜激光诱导损伤阈值（LIDT）计算方法是基于定性或半定量经验公式，所得结果精度和可信度不高。本文提出了一种精确计算薄膜LIDT值的新方法，当薄膜受到强激光照射时，分别构建了内部电场-吸收-温度场的分布模型。一般情况下，当某时刻某深度对应的温度值为薄膜温度场分布中的最大值时，入射激光能量为此时薄膜的损伤能量阈值，深度是薄膜最容易损坏的位置。所以，可以建立损伤能量阈值与最高温度之间的关系表达式，结合临界电子密度与温度最大值和损伤能量阈值的关系表达式，可以得到薄膜的LIDT值同时解决。为了验证该方法的可靠性，分别计算了单层二氧化钛、二氧化硅和类金刚石碳（DLC）薄膜的LIDT值，同时得到了它们的实验值，并分别得到了各薄膜的理论值。值与实验值多次比较，结果表明它们的理论值和实验值是一致的，说明这种计算薄膜LIDT的新方法是可行的，