Colloquia of the Physics, LiMat, and Frimat departments

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November 2017

Wednesday, 29.

Colloquium Physics

How microwaves shed light on topological physics

Prof. Fabrice MORTESSAGNE, Unstitut de Physique de Nice (INPHYNI), Universite Nice Sophia Antipolis &CNRS

Time: 17:15 - 18:15h

Location: UNI-Perolles, Physics Department, building 8, auditorium 0.51, Chemin du Musee 3, 1700 Fribourg, Switzerland

The group Waves in complex systems in Nice (France) is interested in controlling the wave transport properties in various systems whose mastered designs range from homogeneous systems with complex geometries to either (quasi-)periodic or disordered structured materials. Thanks to a versatile experimental platform in the microwave domain, we addressed in the last years the vivid field of topological physics/photonics, and obtained different results ranging from the concept of topological reflective limiter, to a physical interpretation of the gap-labelling in a Penrose tilling, not forgetting the observation of a topological phase transition in strained artificial graphene. During the colloquium, I will give a simple introduction of topological physics, describe the experimental platform, and present a selection of results.

February 2018

Wednesday, 21. - Thursday, 22.

Colloquium Physics

Probing charge dynamics on the femtosecond timescale with photoemission

Prof. Claude Monney, UNIFR, Physics Department

Time: 17:15h

Location: Auditoire de Physique 0.51, Rez-de-chaussee, Perolles 8, Ch. du Musee 3, Fribourg


In the recent years, time-resolved techniques for measuring physical observables on picosecond and femtosecond timescales have developed tremendously, especially with the evolution of commercial laser equipment and the advent of x-ray free electron laser sources.

In this talk, I will introduce the basic principle of pump-probe techniques and will focus on the use of angle-resolved photoemission spectroscopy (ARPES). ARPES is a powerful spectroscopy, since it gives a direct access to the momentum-resolved electronic structure of materials. In its time-resolved version, it allows to probe the ultrafast dynamics of excited charge carriers and of their subsequent relaxation.

I will illustrate the strength of time-resolved ARPES with its application to several materials undergoing phase transitions. Strong infrared pulses are used to excite these materials and to induce a transition from one phase to another. The particular timescale necessary to achieve these changes, as well as the typical subsequent relaxation times, provide hints about the physical mechanisms responsible for the phase transition. I will also give an example of how photoexcitation can generate out-of-equilibrium states of matter, which are not realized at thermodynamical equilibrium.




March 2018

Wednesday, 14.

Department Meeting

Assemblee pleniere du departement de physique / Vollversammlung des Physikdepartements

Physics Departement of the University of Fribourg

Time: 16:15h

Location: UNI-Perolles, Physics Departement, building 8, auditoire 0.51, Chemin du Musee 3, 1700 Fribourg Switzerland


Everyone is invited, general information about the Physics Department and the Faculty are given in this meeting.

The new collaborators will  be introduced during the assembly, please be present!




Sunday, 26.11.2017 - Saturday, 17.03.2018

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