Anisotropic van der Waals Crystal with High Refractive Index and Transparency for UV-Visible Range Applications

TL;DR

This paper introduces germanium disulfide (GeS2) as a transparent, high-refractive-index, anisotropic van der Waals material suitable for UV-visible nanophotonics, filling a critical gap in existing materials.

Contribution

It proposes GeS2 as a novel vdW material with high refractive index and transparency across the visible spectrum, expanding the options for nanophotonic applications.

Findings

GeS2 exhibits high refractive index and optical anisotropy.

GeS2 remains transparent across the entire visible range.

Potential to enhance nanophotonic circuit design.

Abstract

Thanks to their record high refractive index and giant optical anisotropy, van der Waals (vdW) materials have accelerated the development of nanophotonics. However, traditional high refractive index materials, such as titanium dioxide (TiO2), still dominate in the most important visible range. This is due to the current lack of transparent vdW materials across the entire visible spectrum. In this context, we propose that germanium disulfide (GeS2) could offer a significant breakthrough. With its high refractive index, negligible losses, and biaxial optical anisotropy across the whole visible range, GeS2 has the potential to complement TiO2 and close the application gap of vdW materials in the visible spectrum. The addition of GeS2 could have a profound impact on the design of van der Waals nanophotonic circuits for any operation wavelength from ultraviolet to infrared, emphasizing the significance of the potential impact of GeS2 on the field of nanophotonics.