紫外-真空紫外波段的Al+MgF2膜

Al+MgF₂膜是真空紫外波段常用的一种反射膜。根据薄膜光学的电磁场理论计算了正入射条件下Al+MgF₂膜在真空紫外波段的反射率随氟化镁膜厚度的变化规律。研究了Al+MgF₂膜的制备工艺,利用Seya-Namioka紫外-真空紫外反射率计测得Al+MgF₂膜的反射率在150nm～340nm的波段上高于80%。Al+MgF₂膜制备一年后,其真空紫外波段的反射率未有明显变化。

MgF2-overcoated aluminium films for ultraviolet and vacuum ultraviolet

MgF₂-overcoated aluminium films are often used in the spectral range of vacuum ultraviolet. According to the theory of electromagnetism, reflectance of Al+MgF₂ at normal incident was calculated in the way of matrix optics where the optical constant of MgF₂ was taken as a complex number. The effect of thickness of MgF₂ on the reflectance of Al+MgF₂ coatings was considered. The MgF₂ not only prevents the aluminum from being oxidized, but also increases the reflectance of Al+MgF₂ by interference. The reflectance of Al+MgF₂ at incident angle of 10°from 150nm～340nm is above 80% which was measured by Seya-Namioka UV-VUV reflectometer. The reflectance of Al+MgF₂ does not change distinctly after the aging of one year or keeping at the temperature of 55℃ for 12 h. The paper also discusses the preparation of Al+MgF₂ films.