Development of high-performanced 50nm bandwidth rectangular wave filter

Abstract

A method for designing and depositing rectangular wave broadband-pass filter is put forward after a deep study of the nature of the film-filters. A rectangular wave OD3-A broadband-pass filter sample is designed and prepared with this method, with its reference wavelength λ0 =515nm in the working range of 400~1100nm. The average transmittance of the sample in its pass-band of λ0±25nm reaches 92.7%, meanwhile the transmittance in the high-reflective bands of λ ≠ λ0± 25 nm is less than 0.1%. The transmittance of the thin film sample is tested, and the spectrum meet the requirement. It turned out to be a more advanced technology of designing and depositing rectangular wave broadband-pass filter. Compared with the Fabry-Perot Interferometer narrow-band pass filters’ films which needs optical-controlling method, and the traditional film which combines short and long pass filters making the coatings very thick and with low transmittance in transition zone. it is more economical, have more wide range of transmission and the transmittance is higher in the range of pass-band.