Black silicon based iris with reduced light scattering and reflection

Abstract

This paper reports the fabrication and the characterization of a black silicon based iris that shows significant reduction in the unwanted stray light due to scattering and reflection on the iris surfaces. The iris was characterized by recording the far-field diffraction pattern at a 532-nm wavelength. The intensity at dark rings is reduced by a factor of up to 5, which makes the bright 0th order disk much sharper.