Development Of Wide-band Low-noise Filter For Solar Blind Detection System

With the deepening of the research on ultraviolet optics,UV detection technology has been developing towards multi-band,all-round direction.Detecting signals in the ultraviolet blind area(solar blind area)of the solar spectrum can shield the background interference of sunlight and effectively reduce the information processing and it has the advantages of simple structure,high sensitivity,low false alarm rate,etc.,and has attracted wide attention in military defense and other fields.In this paper,a wide-band low-noise optical filter device is developed to meet the technical requirements of the solar blind detection system for high transmission in the solar blind area(200~270 nm)and deep cut-off in the near-ultraviolet to near-infrared area(300~1200 nm).Based on the optical film theory and the analysis of the optical properties of the UV film material,a special film system combining the medium and the metal was designed,and the film system was optimized and analyzed for feasibility.Through the inverse inversion analysis of the actual spectrum of the sample,the main factors leading to the deterioration of the spectrum are identified and the process parameters are further optimized.In order to reduce the aging changes of the film and ensure the stability of the film,a step-by-step deposition method was proposed to complete the preparation of the filter film.The average transmittance of the thin film device developed in this paper reaches 51.76% at 200~270 nm,and the average transmittance at 300~1200 nm is 0.893%.