Preparation of linear variable optical filter in visible spectral region

The linear variable optical filter is a critical spectral splitting component in spectral detection systems. A linear variable optical filter for the 400 nm~700 nm wavelength range using Ta₂O₅ and SiO₂ as high/low refractive index materials was prepared through electron beam evaporation deposition with a planetary workpiece mechanism. A linear film thickness correction model was established by combining revolution motion and fixed correction plates, achieving linearly distributed film thickness uniformity correction through coordinated revolution and rotation of the planetary mechanism, and the calculation methodology for correction plates was described in detail. Spectral characterization was performed by using a Cary7000 spectrophotometer with an integrated in-situ testing fixture, and the influence of thin-film characteristics on spectral transmittance was systematically analyzed.