Quantum devices based on complex oxides
PhD - Leuven | Just now
New cryogenic nonlinear materials are essential for quantum photonic applications, such as efficient photon detection and rf-to-optical qubit transduction. The latter, for instance, can address the RF upscaling challenges in superconducting quantum computing platforms by replacing RF lines with optical fibres. Key for an electro-optic quantum transducer are low optical losses and a high nonlinearity to achieve a unity conversion efficiency. In the past we report on a record cryogenic Pockels coefficient of ~345 pm/V in ferroelectric thin-film strontium titanate using basic test devices [1-2]. Unlike most other room temperature Pockels materials which show a decrease in nonlinearity at cryogenic temperatures, strontium titanate’s Pockels coefficient is strongest at cryogenic temperatures as the ferroelectric/paraelectric phase transition happens at cryogenic temperatures.
In this PhD, we will explore the next generation of more complex quantum devices using SrTiO3 electro-optical technologies and their feasibility to enable the various quantum technologies.
[1] Ulrich, et al (2025), Engineering high Pockels coefficients in thin-film strontium titanate for cryogenic quantum electro-optic applications, arXiv preprint arXiv:2502.14349
[2] Boelen, et al (2024), Stoichiometry and Thickness of Epitaxial SrTiO3 on Silicon (001): an Investigation of Physical, Optical and Electrical Properties, arXiv preprint arXiv:2412.07395
Required background: Masters in Material Science, Physics, Electrical Engineering or Nanotechnology - Experience in Photonics and/or Superconducting Circuits/Qubits is an asset. - Experience in Nanotechnology fabrication is an asset.
Type of work: 50% Experiments (Device fabrication & Characterization), 50% Theory and Device design
Supervisor: Kristiaan De Greve
Co-supervisor: Christian Haffner
Daily advisor: Christian Haffner
The reference code for this position is 2026-027. Mention this reference code on your application form.