J.A. Klärs (Jan)

Associate Professor

About Me

I am an Associate Professor at the Adaptive Quantum Optics Chair. My research group investigates physical phenomena at the interface between thermodynamics and quantum mechanics in optical and optomechanical systems.


Short biography

In 2006, I completed my master’s degree in physics at RWTH Aachen. In my master's thesis, I theoretically investigated statistical properties of magnets and crystal surfaces. For my PhD, I switched to experimental quantum optics working on the Bose-Einstein condensation of photons at the University of Bonn. After finishing my PhD in 2011, I continued to work at the University of Bonn as project leader for the photon Bose-Einstein condensation experiment. In 2015, I moved to ETH Zürich to work on semiconductor optomechanical nanostructures. In September 2017, I started as Assistant Professor at the University of Twente. 


Physics & Astronomy
Bose-Einstein Condensates
Josephson Junctions
Spin Glass



Mattschas, C. U. , Vretenar, M. , Toebes, C. , & Klärs, J. A. (2021). Modified Bose-Einstein condensation in an optical quantum gas. Poster session presented at 44th Annual Meeting NNV AMO Lunteren 2021, Lunteren, Netherlands.
Kurtscheid, C., Dung, D., Redmann, A., Busley, E. , Klaers, J., Vewinger, F., Schmitt, J., & Weitz, M. (2020). Realizing arbitrary trapping potentials for light via direct laser writing of mirror surface profiles. Europhysics letters, 130(5), [54001]. https://doi.org/10.1209/0295-5075/130/54001
Vretenar, M., Kassenberg, B., Bissesar, S. , Toebes, C. , & Klärs, J. A. (2020). Thermo-responsive photonic Josephson junction. Poster session presented at Condensates of Light 2020, Online Workshop.
Vretenar, M., Kassenberg, B., Bissesar, S. , & Klärs, J. A. (2020). Programmable couplings for an all-optical coherent network computer. Poster session presented at Physics@Veldhoven 2020, veldhoven, Netherlands.

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Courses Academic Year  2021/2022

Courses in the current academic year are added at the moment they are finalised in the Osiris system. Therefore it is possible that the list is not yet complete for the whole academic year.

Courses Academic Year  2020/2021

Contact Details

Visiting Address

University of Twente
Faculty of Science and Technology
Horst Complex (building no. 20), room ME123
De Horst 2
7522LW  Enschede
The Netherlands

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Mailing Address

University of Twente
Faculty of Science and Technology
Horst Complex  ME123
P.O. Box 217
7500 AE Enschede
The Netherlands