多脉冲激光对胶合透镜热破坏效应研究

Study on thermal damage to balsaming lens induced by multi-pulse laser

具有一定强度的激光辐照胶合透镜时可造成透镜的破坏.建立了多脉冲激光与材料相互作用的一维非稳态温度场模型,计算了瞬态温度场分布,并对胶合透镜前表面的熔融和胶合材料的软化进行了数值模拟研究.利用频率为10Hz,脉冲宽度为200ns,峰值功率为20MW的CO2激光对胶合透镜进行辐照实验研究.实验表明,当激光辐照时间为12s时,胶合透镜前表面发生熔融破坏;当照射时间为30s时,胶合材料发生软化并出现彩色斑纹,透镜完全破坏,理论分析与实验结果相符.

Balsaming lens will be damaged when irradiated by laser of certain power. The model of one-dimension unstable temperature field during the interaction between multiple-pulse laser and material is established, and the transient temperature distribution of glass material of balsaming lens is calculated. The fusion moment and the moment when cementing material melts are researched by means of numerical calculation. Experiments about damage in several balsaming lenses of the same kind irradiated by multiple-pulse CO2 laser, the parameters of which are 10Hz, 200ns and 20WM, are carried out. It is found that when the irradiation time reaches 12s, the front surface of balsaming lens is molten. When the irradiation time reaches 30s, colorized dapples are suddenly formed in the cementing layer of samples. It indicates that cementing material is intenerated and balsaming lens is thoroughly damaged. The result of theoretical analysis exhibits good agreement with the experimental result.