Three Questions for Humboldt Fellow Dr. Arnault Raymond

What are you currently researching

My research project at TU Dortmund University focuses on photon echoes in semiconductor nanostructures, and in particular on how this phenomenon can be used for quantum information technologies. A photon echo is a phenomenon in which a material system can temporarily store information carried by a light pulse and later re-emit it when it is addressed by another optical pulse. This makes photon echoes particularly interesting for quantum technologies: they could provide a way of storing and retrieving optical quantum information in a solid-state device, forming the basis of a so-called quantum memory. At the same time, photon echoes provide a powerful tool for studying the quantum properties of charge and spin carriers in semiconductors and how they interact with light and with each other.

During my project, I will investigate photon echoes in several semiconductor platforms, including quantum wells, quantum dots and perovskite nanocrystals. One goal is to improve the efficiency of the storage and retrieval of optical signals by integrating these quantum emitters into specially designed optical cavities. Another is to develop advanced optical measurement techniques to enable the full characterization of the quantum properties of the emitted photon echoes. Both goals represent important stepping stones towards the realization of quantum memories based on photon echoes.

To what extent does TU Dortmund University provide a productive environment for your research?

From the scientific perspective, the research group led by Prof. Manfred Bayer and Prof. Marc Aßmann has strong expertise in spectroscopy techniques for semiconductor quantum emitters. The group has pioneered photon echo studies in semiconductor systems, and recently developed an optical homodyne detection scheme, which will be very valuable in characterizing the quantum states of photon echoes. The combination of expertise in ultrafast spectroscopy, quantum optics and semiconductor systems together with a strong theoretical background in spin physics and light-matter interactions provides an ideal environment for this ambitious research project.

There is also a strong connection between fundamental research and technological applications at TU Dortmund University. The local research and innovation ecosystem offers opportunities to explore how fundamental results can eventually translate into new technologies, which is particularly relevant for a project with potential applications in quantum information technologies. Finally, TU Dortmund University provides valuable opportunities for professional and scientific development, including through the University Alliance Ruhr. These networks will allow me to broaden my collaborations and hopefully continue developing some of these research directions beyond the duration of my fellowship.

What do you hope to achieve during your stay, and what makes this international collaboration valuable?

During my stay in Dortmund, I hope to deepen my expertise in semiconductor optics, learn new spectroscopy techniques and explore new research directions at the intersection of fundamental physics, photonics and quantum information. The collaboration is particularly valuable because it brings together complementary expertise in quantum optics and photonic devices on my side, and ultrafast spectroscopy and semiconductor physics at TU Dortmund University. Combining these perspectives allows us to address research questions from different angles and develop new ideas.

Beyond the current project, I hope this collaboration will lead to lasting scientific connections between Germany and France, opening opportunities for future joint projects, knowledge exchange and research stays for students and early-career researchers.

About Dr. Arnault Raymond

Dr. Arnault Raymond received his doctoral degree from Université Paris Cité in 2023, focusing on spatially entangled light in semiconductor photonic circuits. After postdoctoral research on quantum dots and semiconductor nanostructures in France, he joined TU Dortmund University in October 2026 as a Humboldt Research Fellow. 

About the Humboldt Research Fellowship

Awarded by the Alexander von Humboldt Foundation, the Research Fellowship enables experienced international researchers with above-average qualifications to conduct their own project in collaboration with a host at a German research institution. The fellowship addresses postdocs and experienced researchers who have completed their doctoral degree during the last twelve years.