Lithography-Free Chalcogenide Canvas for Photonic Integrated Circuits.

Abstract

Chalcogenide integrated photonic devices have garnered widespread attention due to their excellent wideband transparency. However, current fabrication methods primarily rely on mature silicon-based CMOS processes, which are not readily adaptable to chalcogenides, significantly hindering their development. Here, we present a flexible fabrication approach that judiciously leverages the intrinsic oxidation susceptibility of chalcogenide materials, transforming chalcogenide thin films into a lithography-free canvas for versatile integrated photonic devices. Using antimony sulfide (Sb₂S₃) as an example, we demonstrate low-threshold laser-induced local oxidation using a continuous laser, achieving a refractive index modulation exceeding 0.7 and a spatial resolution of 0.6 μm in the near-infrared region. This technique enables flexible fabrication of various chalcogenide photonic devices. Based on this technique, we further fabricate a dynamic planar Fresnel zone plate, demonstrating dynamic beam focusing by exploiting the phase-change property of Sb₂S₃, as well as high-precision spatial-spectral reconstruction at near-infrared using a millimeter-scale chalcogenide metasurface array. Our findings reveal the potential of chalcogenide thin films as a promising canvas for advanced photonic applications, providing a simplified and versatile fabrication pathway that significantly advances the field of chalcogenide integrated photonic devices.