Tunable spectral filters based on metallic nanowire gratings

Via surface plasmon enhanced light transmission through bilayer metallic nanowire gratings (BMNGs), three pitches of BMNGs with red, green and blue colors are respectively designed and fabricated. The color gamut can reach 89% NTSC in CIE 1931 UCS with optimized design. Furthermore, by utilizing the character of surface plasmon resonance (SPR), which is sensitive to ambient refractive index, the brightness can be tuned to dark by changing the ambient materials. The tunability was demonstrated on a 520 nm gratings in both simulation and experiment, and the obtained contrast ratio is over 120:1. These characteristics indicated a tunable spectral filter based on surface plasmon resonance, promising for a bistable full-color-capability electronic paper display.