深紫外宽入射角范围增透膜设计与制备

摘要

In a large Numerical Aperture (NA) deep Ultraviolet (DUV) optical system, Antireflection (AR) coated optical components with very wide Angle of Incidence (AOI) are used. By employing LaF3/MgF2 as the material combination, we designed three AR thin films that can be used for coating on the wide-angle DUV components with 3-, 5-; and 7-layer structures. Experimentally, we deposited thin films on fused silica substrates by using the thermal boat evaporation, and then measured their spectral properties with a DUV spectrophotometer. The experimental results indicate that the DUV AR coatings with high transmittance in a wide range of AOI were achieved. The residual reflectance of a double-side five-layer AR coated fused silica was measured to be less than 2.5% when AOI varied from 0° to 55°, meanwhile the transmittance was measured to be larger than 98% when AOI varied from 0° to 20°.%在大数值孔径深紫外光学系统中,需要使用宽入射角范围的增透膜光学元件.选择LaF3和MgF2两种镀膜材料,设计了适用于深紫外宽入射角范围的三层、五层和七层三种增透膜系.实验使用热舟蒸发在熔融石英基底上镀制了设计的薄膜,并用紫外分光光度计对其光谱性能进行了测试,得到了在宽入射角范围内具有较高透过率的深紫外增透膜元件.双面镀五层增透膜系的熔石英基片在0°～55°入射角内的剩余反射率小于2.5％,在0°～20°入射角内的透过率大于98％.