基于表面等离子激元的超薄金属减色滤波器的研究

Ultrathin metallic subtractive color filters based on surface plasmon primitives

基于表面等离子激元的新型超薄金属减色滤波器具有可靠、易制备、高透射率等诸多优点.本文对银、铜、铝、镍等不同金属材料的超薄一维光栅减色滤波器进行了系统研究.仿真获得了透射光谱,理论计算了对应透射光谱的色品坐标,并推导出了银、铜、铝三种材料透射率最低点波长与膜厚、周期关系的经验公式.仿真研究发现:除了镍的选波性较差外,银、铜、铝均表现出较好的、不同的滤波特性,其中银的滤波范围较广,而铜、铝则分别在长、短波段表现出较好的滤波性能.为了验证仿真结果,利用磁控溅射技术和聚焦离子束刻蚀技术进行了三种材料的一维光栅减色滤波器的制备实验,并在显微镜下观察滤波器的颜色效应,结果与理论仿真相符合.研究结果表明:不同金属材料在相同微结构下的颜色效应存在较大差异,可根据实际滤波需要,选择材料和微结构参数来获得最佳性价比的滤波器.

Based on the surface plasmon primitives, subtractive color filters fabricated from ultrathin metallic film nanograt- ings, have many advantages, such as reliability, easy fabrication and high transmittance. In this work, color filter behaviors of films of four metals, i.e., silver, copper, aluminum and nickel, with one-dimensional nanogratings are sys- tematically studied. We obtain their transmission spectra, the chromaticity coordinates and the empirical formulas of the relationship of the wavelength of transmission minimum with film thickness and period. It is found that nickel has a poor ability to select waves, which is not an ideal material for color filter. Silver, copper and aluminum perform better in selecting the wavelength. They have different transmission spectra, specifically, silver has a wide range of wavelength selection, copper is appropriate for the long wavelength filtering, and aluminum for short wavelength filtering. To verify the simulation results, we fabricate some one-dimensional nanogratings with different materials by using a direct-current magnetron sputtering system and focused ion beam machine. The experimentally observed colors for all fabricated Ag, Cu, and A1 film nanogratings axe consistent with their simulation results. Both simulation and experimental results reveal that different metal materials and different nanostructures exhibit lager differences in color filter behavior. The obtained results here are useful for designing desirable color filters by selecting the appropriate material and nanostructure.