基于杂质元素控制工艺降低熔石英元件损伤密度实验研究

Experimental Research on Reducing Fused Silica Optics Laser-induced Damage Density Based on Contamination Control Techniques

为降低熔石英元件的损伤密度,本文提出了磁流变抛光与HF酸刻蚀组合工艺降低杂质元素含量的方法。对熔石英样品进行磁流变抛光和HF酸刻蚀,测试表面的杂质元素相对含量以及355nm激光辐照下的损伤密度。磁流变抛光后,熔石英元件表面的Ce元素相对含量由2694当量降至10当量以下,但Fe元素相对含量由376.2当量上升至4333当量,8J/cm2通量下损伤密度由0.49个/mm2增大为0.90个/mm2;磁流变抛光与HF酸刻蚀后,Fe元素相对含量下降至1951当量,损伤密度为0.042个/mm2。实验结果表明,磁流变抛光可以去除前级加工引入的Ce元素,但是会引入Fe元素,导致损伤密度上升。HF酸刻蚀可以有效降低杂质元素含量,降低损伤密度。

In order to reduce the fused silica optics damage density, the method of controlling the content of contamination elements by magnetorheological finishing（MRF） and HF acid etching was put forward. MRF and HF acid etching were used on the fused silica plates, the relative content of contamination elements of the plates surface and the damage density on 355 nm laser were tested. The experimental results show that MRF can wipe off the Ce element produced in the front-end process, but because of leading in Fe element, the damage density rises. HF acid etching can reduce the content of contamination elements effectively and the damage density.