Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 37: Poster IV

HL 37.28: Poster

Wednesday, March 20, 2024, 18:00–20:30, Poster F

Probing the ultrafast dynamics of photonic devices based on phase change materials — •Nils Weber, Sebastian Walfort, Niklas Vollmar, and Martin Salinga — University of Münster, Institute of Materials Physics, Wilhelm-Klemm-Str. 10, 48149 Münster

Phase change materials (PCMs) are compounds typically composed of germanium, tellurium and antimony. They are characterized by a strong contrast in electrical and optical properties between crystalline and glassy states. Combined with the ability to switch rapidly between crystal and glass, this contrast makes them an interesting material system for non-volatile memory elements in electronic and photonic circuits. By using photons instead of electrons as signal carriers, photonic circuits are free from the bandwidth constraints associated with electrical circuits and are therefore sensitive to material dynamics on picosecond timescales. The implications and potential new applications of operating the PCM-based memory elements at these bandwidths remain largely unexplored. Here we present the design and implementation of an experimental setup capable of resolving the ultrafast response of photonic devices. Our approach combines an amplified femtosecond free-space laser with fiber coupled ultrafast light sources in a setup with sufficient spatial resolution to address individual microscopic devices. We show first experimental results together with finite element simulations of the transient response of PCM-based optical weights as used in photonic integrated circuits for in-memory computing.

Keywords: Phase change materials; Photonic computing; Experimental setup; Pump-probe spectroscopy