Optothermally Controlled Charge Transfer Plasmons in Au-Ge2Sb2Te5 Core-Shell Assemblies

TL;DR

This paper demonstrates how phase-changing Ge2Sb2Te5 shells on gold cores enable optothermal control of charge transfer plasmon resonances, advancing tunable nanophotonic device development.

Contribution

It introduces a novel gold-GST core-shell dimer design that achieves tunable plasmonic resonances through phase change without altering geometry.

Findings

Achieved tunable dipolar and CTP resonances in the near-infrared spectrum.

Demonstrated phase change control from amorphous to crystalline states.

Enabled potential for fast, reconfigurable plasmonic devices.

Abstract

Tunable plasmonic resonances across the visible and near infrared spectra have provided novel ways to develop next-generation nanophotonic devices. In this study, by using optothermally controllable phase-changing material (PCM), we successfully induced highly tunable charge transfer plasmon (CTP) resonance modes. To this end, we have designed a two-member dimer assembly including gold cores and Ge2Sb2Te5 (GST) shells in distant, touching, and overlapping conditions. We successfully demonstrated that toggling between amorphous (dielectric) and crystalline (conductive) phases of GST allows for achieving tunable dipolar and CTP resonances along the near-infrared spectrum. The proposed dimer structures can help forming optothermally controlled devices without further geometrical variations in the geometry of the design, and having strong potential for advanced plasmon modulation and fast data routing.