RP1: 01.04.2018 - 30.09.2019
We have started to set up the laboratory, including massive optical tables with a weight of many tons to provide a stable environment, we have set up the first laser systems and electronics, and designed the vacuum chamber in which the experiments will take place. Further, we have visited almost all other groups in Europe working on complementary approaches to measure the EDM, and organized a symposium on the occasion of the opening of the lab. Hired two PhD students and a number of internship students
RP2: 01.10.2019 - 31.03.2021
Our first magneto-optical trap of mercury, followed by detailed characterization and improvement of experimental parameters (Phys. Rev. A 105, 033106 (2022)). Set up an ultrastable cavity as frequency reference of the 254-nm laser.
RP3: 01.04.2021 - 30.09.2022
First optical dipole trapping of laser-cooled atoms, but the trap depth is not sufficiently deep to provide stable trapping. A new laser system is installed to provide sufficient trap depth. Also, a new experimental control system allows for high-resolution careful adjustment of experimental parameters. We commence isotope shift spoctroscopy on the 254-nm transition with unprecedented precision (1/1000 of the natural linewidth).
RP4: 01.10.2022 - 31.03.2024
We continue the isotope shift measurements and data evaluation on two further transitions near 313 nm, and prepare for a fourth set of measurements near 436 nm. To prepare for the dipole trapping and evaporative cooling experiments, we set up an entirely new vacuum chamber, explore new vacuum windows and sealing technology, refurbish the oven, and re-build the entire optical pathway.
RP5: 01.04.2024 - 31.03.2025
The focus shifted back to the optical dipole trapping of laser-cooled mercury atoms. Here, a new high-power laser system has been installed, with a new optical pathway for switching and control of the trap. A second trap axis has been added for axial confinement. Atoms have successfully been trapped in this crossed-beam dipole trap, and measurements of thermalization rates, which return information about scattering properties, have been initiated. Secondly, the setup of the 185-nm laser system been started. Thus far, a frequency-quadrupled system near 215 nm has been installed, a pump laser near 1300 nm has been installed, and the resonant sum-frequency-mixing stage has been set up.
Overview of results:
Construction of a laser-cooling experiment for mercury (described in various master and PhD theses), improved magneto-optical trapping (Phys. Rev. A 105, 033106 (2022)) and dipole trap loading (publication in preparation) of Hg atoms. Isotope shift spectroscopy (publication in preparation) to constrain nuclear parameters. Development of lasers in the range of 213 nm via two consecutive SHG stages (Phys. Rev. A 109, 012806 (2024), further manuscripts currently under review) and at 185 nm. Out of technology development performed in this project, ring laser gyroscopes emerged as a new topic with potential applications to search for physics beyond the standard model.
