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journal article·2026-05-01Open access

Temperature-dependent refractive index of AlGaAs for quantum-photonic devices near the bandgap

M. Langer, S. A. Dhurjati, M. Bauer, Y. G. Zena, A. Rahimi, R. Bassoli, F. H. P. Fitzek, O. G. Schmidt, C. Hopfmann

AIP Advances· Volume 16· Issue 5
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Source abstract

Abstract

We present an experimental method to determine the refractive index of AlxGa1−xAs (x = 0.0–0.5) from 300 to 4 K across the 500–1100 nm wavelength range. The values are extracted from spectroscopically observed microcavity resonances in thin AlGaAs membranes embedded between fully and partially reflective gold mirrors. Refined Varshni and Paessler models are used to describe temperature-dependent bandgap shifts and material composition. By tracking resonance shifts and benchmarking against finite-difference time-domain simulations, we derive the dispersive optical response with high precision. This approach yields a quantitatively improved analytical expression for the refractive index n of AlGaAs, achieving modeling accuracy by a coefficient of determination of up to R2 = 0.993, at a maximal experimental uncertainty of Δn = 0.0647. Consequently, it enables accurate modeling in the vicinity of the band edge and revises the quadratic dependence of the refractive index on temperature. The method is straightforward and broadly applicable to other semiconductor systems, offering a valuable tool for the design of microphotonic devices, such as quantum light sources.
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Research context

Electronic materials

OpenAlex topics: Plasmonic and Surface Plasmon Research · Semiconductor Quantum Structures and Devices · Strong Light-Matter Interactions

SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.

Affiliations

Institute for Emerging Electronic Technologies, IFW Dresden 1 , Helmholtzstraße 20, 01069 Dresden,

Quantum Communication Networks Research Group, Deutsche Telekom Chair of Communication Networks, Technische Universität Dresden 2 , Dresden,

Deutsche Telekom Chair of Communication Networks, Technische Universität Dresden 3 , Dresden,

Research Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology 4 , Chemnitz,

Funding

German Federal Ministry of Research, Technology and Space and Researchproject QR.N · German Federal Ministry of Research, Technology and Space and Researchproject QUARKS · German Federal Ministry of Research, Technology and Space and Researchproject QUIET · German Federal Ministry of Research, Technology and Space and Researchproject QD-CamNetz · German Federal Ministry of Research, Technology and Space and Researchproject 6G-life · German Federal Ministry of Research, Technology and Space and Researchproject Community · German Research Foundation and Researchproject CeTI

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