Interfacing Photonics with Atoms and Ions for Compact and Robust Quantum Technologies
Stefanie Kroker, Technische Universitat Braunschweig, Germany
Metamaterials That Vary in Time Unlock Superluminal Motion
Riccardo Sapienza, Imperial College London, United Kingdom
Interfacing Photonics with Atoms and Ions for Compact and Robust Quantum Technologies
Stefanie Kroker
Technische Universitat Braunschweig
Germany
Brief Bio
Stefanie Kroker studied Physics at Friedrich Schiller University in Jena/Germany and Universidad de Granada/Spain. She did her PhD with the Institute of applied Physics at Friedrich Schiller University in 2014 and became assistant professor at TU Braunschweig and the German national metrology institute, PTB in 2016. In 2020 Stefanie Kroker received the Science Award Lower Saxony and in 2021 she was appointed to a full professorship at TU Braunschweig. She is a member of the German clusters of excellence QuantumFrontiers and PhoenixD. In 2024 she was awarded with a Consolidator Grant by the European Research Council. Her field of research are photonic systems for applications in high-precision optical metrology and quantum technologies. Since 2022, she has been an associate editor for APL Quantum.
Abstract
Integrated photonics plays a key role in enabling compact systems for light routing and conditioning with increasingly complex optical functions. By offering scalability in both ensemble size and system complexity, it enables robust quantum technologies based on trapped atoms and ions.
In addition to photonic systems for trapping, cooling, and addressing atoms and ions, ultra-stable lasers (USLs) are essential for providing the stable frequencies needed to interrogate narrow atomic transitions with high precision. USLs are also at the heart of precision measurements, such as gravitational wave detection and fundamental physics tests. Current USLs achieve a relative instability of 4×10⁻¹⁷, currently limited by resonator thermal noise. However, current setups are bulky and would significantly benefit from photonic integration, for example, of input/output optics, sensing elements, and devices needed for laser stabilization.
In this talk, I will present an overview of integrated photonic devices for quantum sensing and computing with trapped atoms and ions. I will discuss the physical requirements and key material considerations for these applications and introduce a novel resonator concept based on multifunctional mirrors designed to meet stringent requirements on size, weight, and noise in next-generation quantum systems.
Metamaterials That Vary in Time Unlock Superluminal Motion
Riccardo Sapienza
Imperial College London
United Kingdom
Brief Bio
Riccardo Sapienza is Professor of Physics in Imperial College London, and deputy Head of Department for Research. He has experience in light control in nanoscale architectures, complex lasers and metamaterials. He is the director of the Centre for Plasmonics and Metamaterials and has been awarded an ERC Advanced Grant in 2025 to explore programmable metamaterials.
Abstract
Metamaterials have revolutionised the way we control light transport and generation. Yet, to date, they rely on static and passive architectures, only redistributing incident wave energy - for example a metalens that focuses light or a cloak that makes an object invisible. The next frontier is to control metamaterials in space and time, and make waves from the past and future to interact.
I will discuss our first steps towards temporal control and experiments on double-slit time diffraction at optical frequencies in time-varying metamaterials [1]. Intertwining space and time, I will discuss the observation of scattering of light from optical modulations traveling faster than the speed of light [2], and coherent perfect absorption [3] and how this will enable us to simulate more complex spatio-temporal optical and relativistic phenomena.
References
[1] Double-slit time diffraction at optical frequencies, Romain Tirole, Stefano Vezzoli, Emanuele Galiffi, Iain Robertson, Dries Maurice, Benjamin Tilmann, Stefan A Maier, John B Pendry, Riccardo Sapienza, Nature Physics 19, 999 (2023).
[2] Super-luminal Synthetic Motion with a Space-Time Optical Metasurface A. C. Harwood, S. Vezzoli, T. V. Raziman, C. Hooper, R. Tirole, F. Wu, S. A. Maier, J. B. Pendry, S. A. R. Horsley, R. Sapienza, Nature Communications 16, 5147 (2025)
[3] Optical coherent perfect absorption and amplification in a time-varying medium, Emanuele Galiffi, Anthony C. Harwood, Stefano Vezzoli, Romain Tirole, Andrea Alù, Riccardo Sapienza, Nature Photonics in press and ArXiV 2410.16426 (2025)