Unveiling the In-plane Anisotropic Dielectric Waveguide Modes in α-MoO3 Flakes

Abstract

Abstract The unique in-plane and out-of-plane anisotropy of α-MoO3 has attracted considerable interest for potential optoelectronic applications. However, most research has focused on the mid-infrared spectrum, leaving its properties and applications in the visible and near-infrared light spectrum less explored. This study advances the understanding of waveguiding properties of α-MoO3 by near-field imaging of the waveguide modes along the [100] and [001] directions of α-MoO3 flakes at 633 nm and 785 nm. We investigated the effects of flake thickness and documented the mode's dispersion relationship, which is crucial for tailoring α-MoO3's optical responses in device applications. Our findings enhance the research field of α-MoO3, highlighting its utility in fabricating next-generation optoelectronic devices for its unique optically anisotropic waveguide.