Understanding Inhomogeneous Crystallization Dynamics of Phase‐Change Materials in the Vicinity of Metallic Nanoantennas

Advanced Optical Materials

Abstract

ABSTRACT Optical metasurfaces composed of metallic or dielectric scatterers (meta‐atoms) promise a powerful way of tailoring light‐matter interactions. Phase‐change materials (PCMs) are prime candidates for non‐volatile resonance tuning of metasurfaces based on a refractive index change. Precise resonance control can be achieved by locally applying laser pulses to crystallize a PCM, modifying the dielectric surrounding of meta‐atoms. However, the complex crystallization kinetics of PCMs in the vicinity of metallic meta‐atoms have not been studied yet. Here, we experimentally investigate metallic dimer antennas on top of the PCM Ge 3 Sb 2 Te 6 and address these nanoantennas with laser pulses. Our study reveals inhomogeneous crystallization caused by the absorption and heat conduction of the metallic nanoantennas. A self‐consistent multiphysics model, including electromagnetic, thermal, and phase‐transition processes, is employed to simulate the crystallization and understand the resulting resonance shift of the antennas. Our work paves the way toward complex antenna geometries optimized for local addressing of PCMs to achieve sophisticated crystallization patterns, enabling on‐demand programming of individual nanoantennas within metasurfaces.

Authors 8

1. Luis Schüler corresponding Aachen AMO GmbH Aachen Germany I. Institute of Physics (IA)

   AMO (Germany) · RWTH Aachen University

   Affiliation as printed

   AMO GmbH Aachen Germany

   I. Institute of Physics (IA) RWTH Aachen University Aachen Germany

2. Lukas Conrads Aachen I. Institute of Physics (IA)

   RWTH Aachen University

   Affiliation as printed

   I. Institute of Physics (IA) RWTH Aachen University Aachen Germany

3. Yingfan Chen Aachen I. Institute of Physics (IA)

   RWTH Aachen University

   Affiliation as printed

   I. Institute of Physics (IA) RWTH Aachen University Aachen Germany

4. Lina Jäckering Aachen I. Institute of Physics (IA)

   RWTH Aachen University

   Affiliation as printed

   I. Institute of Physics (IA) RWTH Aachen University Aachen Germany

5. Sebastian Meyer Aachen I. Institute of Physics (IA)

   RWTH Aachen University

   Affiliation as printed

   I. Institute of Physics (IA) RWTH Aachen University Aachen Germany

6. Matthias Wuttig Aachen I. Institute of Physics (IA)

   RWTH Aachen University

   Affiliation as printed

   I. Institute of Physics (IA) RWTH Aachen University Aachen Germany

7. Thomas Taubner Aachen I. Institute of Physics (IA)

   RWTH Aachen University

   Affiliation as printed

   I. Institute of Physics (IA) RWTH Aachen University Aachen Germany

8. Dmitry N. Chigrin corresponding Aachen AMO GmbH Aachen Germany I. Institute of Physics (IA)

   AMO (Germany) · RWTH Aachen University

   Affiliation as printed

   AMO GmbH Aachen Germany

   I. Institute of Physics (IA) RWTH Aachen University Aachen Germany