Canalization-based super-resolution imaging using an individual van der Waals thin layer

Abstract

Canalization is an optical phenomenon that enables unidirectional light propagation without predefined waveguiding designs. Recently demonstrated using phonon polaritons in twisted van der Waals (vdW) layers of α-MoO₃, it offers unprecedented possibilities for controlling light-matter interactions at the nanoscale. However, practical applications have been hindered by the complex sample fabrication of twisted stacks. In this work, we introduce a previously unexplored canalization phenomenon in a single-thin vdW layer (α-MoO₃) interfaced with a substrate exhibiting a given negative permittivity. This enables a proof-of-concept application of polariton canalization: super-resolution nanoimaging (~λ₀/220). Canalization-based imaging transcends conventional projection constraints, allowing the super-resolution images to be obtained at any desired location in the image plane. This versatility stems from the synergetic manipulation of three key parameters: incident frequency, rotation angle of the thin vdW layer, and thickness. Our results provide insights into the properties of canalization and constitute a seminal step toward multifaceted photonic applications, including imaging, data transmission, and ultracompact photonic integration.