Towards the detection of vacuum birefringence Speaker: Gerhard Paulus (Helmholtz Institute Jena) Date: Wednesday, 26 April 2023, 4pm CEST Strong electromagnetic fields polarize vacuum such that it becomes birefringent. Not surprisingly, the effect is tiny, even if petawatt-class lasers are used for inducing the effect and X-ray lasers for probing it. Quite obviously, the performance of the required X-ray polarimeters is the decisive bottleneck: an extinction ratio of 1011 or better is required. Gerhard Paulus and his team have been working since more than 10 years to remove the bottleneck. He will report how close they have come to the feasibility of a promising demonstration of vacuum birefringence. He will also explain how to design a reasonable experiment and which mistakes to avoid. -- Laserlab-Europe Talks is a series of online seminars and panel discussions proposed and organised by our community on specific topics (thematic or research-specific) and provide a platform for regular information exchange and knowledge sharing. The Talks take place monthly on a Wednesday afternoon at 4pm CEST and are open to all interested parties, from PhD students to experts in the field and industrial and medical partners. Previous Talks can be watched on our YouTube channel.