利用唯象模型解释和理解弱吸收下降曲线

观察到了光学基片和薄膜元器在准连续激光辐照下发生了预处理效应。在532 nm和355 nm激光辐照下，许多样品的弱吸收值呈现出一个相似的下降曲线（ADC）；但在1064 nm激光辐照下没有此现象。为了解释和进一步理解该现象，合理假设该现象与辐射总能量密度有关，以此建立了一个唯象模型，并进行了一系列推算。推算结论指出：ADC的初始部分形状更多与具体发生的激光预处理机制有关，而尾部形状更多是由于高斯光分布所致；归一化后的ADC以及归一化后的上渐近线，将成为多个ADC曲线之间进行比较的天然度量衡。这些推论得到了实验数据的支持。

Phenomenological model to understand weak absorption decreasing curves

Conditioning effect on several kinds of optical substrates and film components by quasi-CW laser was investigated. Many samples showed absorption decreasing curves (ADC) under 532 nm and 355 nm irradiation, while keeping absorption values under 1064 nm irradiation. A phenomenological model was built to understand ADC. The model was based on that ADC should be mainly related to accumulated irradiation energy density. According to the model, the head part of ADC was influenced more by mechanism of laser conditioning, and the tail part formed mainly from Gaussian Beam. Normalized ADC and normalized high-asymptote parameter were considered as two tools to make comparison among different curves and get some mechanism information by the model. The results of re-analysis experiment data supported the model, and indicated that the real curves were more like e model shape.