Regensburg 2025 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 8: Measurement Technology and Cryogenics

TT 8.9: Talk

Monday, March 17, 2025, 17:15–17:30, H32

Erbium dopants as luminescence thermometers in nanophotonic silicon waveguides — •Kilian Sandholzer, Stephan Rinner, Justus Edelmann, and Andreas Reiserer — Technical University of Munich, TUM School of Natural Sciences, and Munich Center for Quantum Science and Technology (MCQST), Garching, Germany

The demand for fast and accurate temperature measurements in nanophotonic silicon devices grows as integrated structures for applications become more complicated and denser in classical and quantum technologies. Established approaches use sensors attached close to the components, which limits spatial resolution and increases the footprint of devices [1]. We propose and implement luminescence-based thermometry using directly integrated erbium emitters within nanophotonic silicon waveguides [2]. Coverage from 2 K to 295 K is achieved using two different effects: The thermal activation of non-radiative decay channels via impurities is used for temperatures above 200 K, and the population dynamics of crystal field and spin levels caused by phononic thermalization at lower temperatures. We achieve relative thermal sensitivities of 0.22(4) %/K at room temperature, increasing to 420(50) %/K at 2 K. Combined with spatially selective implantation, our method promises precise thermometry from ambient to cryogenic temperatures with a few-nanometer resolution.

[1] Y. Ma, B. Dong, and C. Lee, Nano Convergence 7, 12 (2020)

[2] K. Sandholzer et al., arXiv (2024)

Keywords: Rare-earth dopants; Erbium-doped silicon; Ratiometric thermometry; Boltzmann thermometry; Silicon nanophotonics