Dynamic spectral control: Incident Angle-Responsive Tuning of High-Purity Structural Colors with Dielectric Nanovoid Arrays

We demonstrate incident-angle-dependent tuning of visible structural colors using a nanovoid array on a silicon surface fabricated via focused ion beam nanolithography. The method achieves enhanced structural color purity and resolution, as evidenced by sharp peaks in reflectance spectra. A linear correlation between the reflected wavelength and variations in periodicity or incident angle underscores the potential for efficient structural color tuning through manipulation of material properties, instrumental parameters, or both. To explain the observed reflectance shifts, we analyze two key physical phenomena: Mie resonance and light diffraction. Our findings reveal that the nanovoids serve a dual role, acting as Mie-voids while simultaneously functioning as elements in a crossed-diffraction grating system. This dual functionality enables precise spectral control, demonstrating the versatility of nanovoid arrays for optical manipulation. The study offers valuable insights into structural color engineering, paving the way for advancements in photonic and color-tuning technologies.