Wide-angle reflective-type color filter in the visible range

A reflective-type color filter in the visible range is theoretically investigated. It consists of a transparent flexible substrate, a layer of thick metal, and two-dimensional dielectric-metal grating. The filter proposed here has the advangtages of insensitivity to incident-angle and polarization-independence. It is found that the variations of its geometric parameters can tune the selective wavelength to generate different colors. The angular dependence of the reflection spectrum for TM and TE polarized light is simulated and analyzed. The position of the reflection valley and the full-width at half-maximum (FWHM) remain almost unchanged when the incident angle is increased to 30 degree. The useful future of the structure is the low dependence of the reflection spectrum on the incident-angle and the polarizations which can be utilized for reflective display.