基于黑色层纳米薄膜的可重构可见光滤波器

A novel reconfigurable visible light filter based on nanofilms with a black layer was proposed in view of the tunable dielectric properties of ferroelectric materials. The reconfigurable performance of its reflection spectrum was compared with that of the one-dimensional photonic crystal filter. The experimental results demonstrate that the reflection color contrast is significantly improved by the black layer that absorbs the incoherent scattered light. When the thickness of the barium titanate (BTO) film changes from 100 nm to 140 nm, the peak wavelength of the reflection spectrum shifts from 383.7 nm to 501.2 nm, and the reflection color turns from purple to turquoise. The test results of the reflection spectra are in good agreement with the finite element simulation outcomes. According to the numerical results, when the BTO film is 170 nm thick, its refractive index decreases from 2.4 to 2.0 under 21.8 V direct-current (DC) driving voltage. Consequently, the peak wavelength of the reflection spectrum shifts from 595.3 nm to 513.9 nm.