Lithography-free patterning of chalcogenide materials for integrated photonic devices

TL;DR

This paper introduces a novel laser-induced oxidation method for patterning chalcogenide materials, enabling lithography-free fabrication of integrated photonic devices with high resolution and versatile functionalities, overcoming fabrication challenges related to oxidation sensitivity.

Contribution

The work presents a new laser-induced localized oxidation technique for patterning chalcogenide thin films, eliminating the need for lithography and simplifying fabrication of integrated photonic devices.

Findings

Achieved localized multi-level oxidation with a refractive index contrast of 0.7.

Demonstrated various photonic devices including color printing and spatial light modulation.

Enabled switchable beam focusing using phase-change properties of Sb2S3.

Abstract

Chalcogenide material-based integrated photonic devices have garnered widespread attention due to their unique wideband transparency. Despite their recognized CMOS compatibility, the fabrication of these devices relies predominantly on lithography techniques. However, chalcogenide thin films are highly susceptible to oxidation, necessitating customized process flows and complex protective measures during lithography. These requirements are hardly compatible with current commercial CMOS manufacturing platforms designed for silicon photonics, significantly limiting the practical applications of chalcogenide photonic devices. In this work, we ingeniously exploit the ease of oxidation of chalcogenide materials, presenting a novel laser-induced localized oxidation technique for spatial patterning on chalcogenide thin films, enabling concise lithography-free fabrication of chalcogenide integrated photonic devices. Using Sb2S3 as an example, we experimentally demonstrate localized multi-level oxidation with a sizable overall refractive index contrast of 0.7 at near-infrared, featuring a high spatial resolution of 0.6 um. Based on this technique, multiple integrated photonic devices are demonstrated, showing versatile functionalities, including color printing at visible and metasurface-based spatial light modulation at near-infrared regions. Leveraging the inherent phase-change property of Sb2S3, an active Fresnel zone plate, enabling switchable beam focusing, is further demonstrated, indicating the feasibility of concise fabrication of active photonic devices. Our work offers a brand-new modulation dimension for chalcogenide materials and provides a significantly simplified approach for realizing chalcogenide-integrated photonic devices.