亚表面杂质对熔石英激光损伤的影响

摘要

采用HF酸对熔石英材料刻蚀不同的时间,利用同步辐射X射线荧光成像方法(SXRF)研究熔石英材料亚表面区域的杂质种类和相对含量,利用AFM和白光干涉仪研究刻蚀区域表面形貌和表面粗糙度,并采用R:1方式测试激光损伤阈值.实验结果表明,熔石英亚表面的杂质主要包括Fe、Cu、Ce,其相对含量随刻蚀时间的增加而降低.在刻蚀时间小于30 min时,损伤阈值明显提升；继续增加刻蚀时间,阈值降低.当刻蚀时间较短时,Cu、Ce等杂质含量对损伤阈值影响较大.刻蚀时间过长时,元件表面粗糙度成为影响损伤阈值的主要因素.%Fused silica with different etching time were obtained by HF acid etching. The variation and distribution of inclusions were analyzed by synchrotron X-ray fluorescence spectrometry. The relative concentrations of main inclusions, such as Fe, Cu and Ce, are decreased with the increase of etching time. The AFM and Wyko images of the samples show that the surface roughness increase with the increase of etching time. The R:l test procedure has been adapted to the pre-etching samples. The laser induced damage threshold (LIDT) increases within 30 min etching time and rapidly decreases to the threshold of non-etching fused silica level. The result indicates that Cu, Ce concentrations plays important role at low etching time, whereas when etching time is too long, the decreased LIDT is attributed to the increment of surface roughness.