Abstract

We present a systematic study of the optical properties of dielectric gratings with symmetric V-shaped ridges having a 90 degree apex angle and refractive index $n$. Such structures exhibit completely different optical properties if the dimensions are scaled with respect to the vacuum wavelength ${\lambda }_0$ of light. In the subwavelength domain, where the grating period $d$ is less than ${\lambda }_0/n$, the grating behaves as an antireflection layer. In the large-period domain $d\gg {\lambda }_0$ (with normal incidence from the dielectric side), the grating turns into a micro-retroreflector array. The transition between these well-known domains is studied using rigorous diffraction theory. The results are verified experimentally by fabricating and characterizing V-profile gratings with the aid of wet etching of silicon using a process that defines a 90 degree apex angle and replication into a polymer.

© 2017 Optical Society of America

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