Preparation of 157 nm Fluoride Optical Thin Films

In order to develop low loss,high-performance 157 nm fluoride coatings,157 nm fluoride optical thin film performance is studied.On the base of fluorede single layer study,157 nm HR and AR coatings are designed and deposited with different fluoride high and low refractive index materials.Their reflectivity,transmittance,optical loss and other properties are discussed and compared.In the analysis of several fluoride films and their combined properties,the fluoride combinations of 157 nm HR and AR coatings are optimized selected.To get a high-performance 157 nm HR coating,the NdF3/AlF3 HR mirror is designed and made,and its reflectance is nearly up to 93%.Under the present experimental conditions,the LaF3/AlF3 157 nm AR coanting is designed and deposited,and its residual reflectance is less than 0.17%.