The miniaturization of optical components is a challenge in photonics. Researchers at the Karlsruhe Institute of Technology (KIT) and Friedrich Schiller University Jena have succeeded in developing a diffuser - an optical scattering disk - based on silicon nanoparticles. This enables them to specifically control the direction, color and polarization of light.
Diffusers are scattering disks that use small scattering centers to influence incoming light and distribute it evenly in all directions. In order to replace rather massive traditional diffusers, researchers from KIT and Friedrich Schiller University Jena applied a layer of special silicon nanoparticles to a substrate. They distributed the particles in a disordered but carefully planned manner. The scattering disks were produced using ion beam lithography and reactive ion etching in a multi-stage process. The direction, color and polarization of light can be specifically controlled with these meta-surfaces.
When viewed with the naked eye, the metasurface diffusers appear equally bright from all directions; they scatter light of a certain color and allow other wavelengths to pass through undisturbed. This property is useful for scientific applications, for example, but also benefits consumer products such as transparent screens that can be viewed from both sides, holographic projectors or augmented reality headsets.
