It's the end of the winter break and the beginning of the summer term, and there has been some shuffling within the team. Katrin and Priyanka finish their master theses: Katrin worked in the frequency conversion, while Priyanka had worked with us previously and now did a master thesis with our beloved friend Tommaso Calarco in Jülich. Benny joined us from Heidelberg for part of his master thesis on xenon spectroscopy, and Johanna will join us for her bachelor thesis on the Sr MOT experiment. And we welcome back Sascha, who officially begins his PhD thesis on the mercury experiment. All the best to all of you! 

Time passes quickly: we are celebrating already the 7th birthday of our research group. What started in April 2018 with no labs and no offices has grown into a vibrant team of nearly 20 people operating eight full-fledged optics labs. Sadly, it's also the end of the quMercury ERC project, which went through two extensions and shaped the first seven years of our group. But no worries, the quMercury project made it into the community input for the European Strategy for Particle Physics Update!

We'll have the DPG Spring Meeting⁶ coming up next week, with around 1600 AMO folks coming to Bonn. We will be contributing 6 talks and 7 posters, so watch out for the Quantum Metrology logo! We will offer lab tours on Tuesday, Wednesday, and Thursday at 2 pm and 5 pm, starting from the main entrance of the Physics Institute at Nussallee 12. Get in touch with us if you want to see the labs and learn more about our work. A big THANK YOU goes to Sebastian Hofferberth an his team for organizing the conference. 

In German, there is a saying "Am Aschermittwoch ist alles vorbei", which might be translated as "Everything ends on Ash Wednesday". Keeping with this saying, David Röser had his PhD defense today (Ash Wednesday!) to finish his PhD thesis not in ashes, but with a large celebration on a beautiful sunny day. The title of his thesis reads "Spectroscopy and the Path to Laser Cooling of Zinc", and David indeed developed a range of components and procedures that form the foundation of our Zinc experiment. Congratulations, Dr. Röser! 

Here it is: our first publication on ring laser technology⁷ has been published with Optics Letters! Jannik set up two schemes to lock the free spectral range of GeoRG, our largest ring laser with an arm length of 3.5 meters. A simple phase lock is sufficient to keep the perimeter length constant to within 5 nanometers.