Silicon Rich Nitride Huygens Metasurfaces in the Visible Regime

Abstract In recent years there has been a shift of interest in the Nanophotonics community moving from using metallic/plasmonic materials to using high‐index dielectric materials for the construction of metasurfaces. Although high‐index dielectrics hold many advantages over their plasmonic counterparts, the selection of materials that exhibit high‐index properties, have low loss, and are complemetary metal‐oxide‐semiconductor (CMOS) compatible that also operate in the visible regime is extremely challenging. In this work, a high‐index dielectric material using silicon rich nitride (SRN) is proposed and experimentally demonstrated as a platform for solving this problem. While SRN has been used before for diffractive lenses and structural colors, here its applicability for Huygens‐type metasurfaces is focused upon. Specifically, a Huygens metasurface that operates in the visible range around a wavelength of 575 nm is theoretically and experimentally demonstrated, and the capabilities of spatially controlling the phase of this metasurface are further demonstrated by designing and fabricating a Huygens meta hologram. The study also shows that the refractive index can be controlled by the interplay between SiH₄ and NH₃ during the plasma‐enhanced chemical vapor deposition (PECVD) process.