高精度干涉仪针孔空间滤波器研制

应用于高重复频率、高功率193 nm准分子激光器会聚光路中的针孔空间滤波器，除了需要考虑它的材料加工难易、厚度、针孔尺寸等因素外，还需考虑材料抗激光损伤特性。本文利用激光损伤理论中一维热流模型对无限厚和有限厚不同金属样品在高峰值功率193 nm 准分子激光器照射下的损伤阈值进行了分析。结果表明：铝材料在厚度为1.2μm处比其它金属的损伤阈值高，可达1.16×1010 W/cm2，且材料易于加工。利用聚焦离子束技术加工了航空铝材料样品，得到了厚度为1.2和1.5μm的针孔空间滤波器样品。扫描电镜观察其具有较好圆度和内壁粗糙度，基本满足剪切干涉仪对针孔空间滤波器的需求。

Development of pinhole filter in high precision interferometer

When the pinhole filter is applied in the converging illuminating optics of a 193 nm excimer laser with high repetition rate and high power , the laser-induced damage threshold of the pinhole filter should also be considered besides the fabrication feasibility , thickness and the pinhole size .In this paper , one dimension-al conduction mathematic model based on laser-induced damage theory is used to analyse the laser-induced damage threshold for different thickness metals illuminated by the high power 193 nm excimer laser .The re-sults indicate that Al has a higher laser-induced damage threshold of 1.16 ×1010 W/cm2 at 1.2μm thickness. Furthermore, the Al also has the advantage of easy fabrication .Ion beam machining method is used to fabri-cate the pinhole filters with diameters of 1.2μm and 1.5μm and the obtained sample are observed by a scan-ning microscope .It shows that the pinhole filters have good roundnesses and inner roughnesses , which almost satisfies the need of a shearing interferometer .