Successful start of the BMBF project "UV-KrisP - Coherent continuous wave radiation in vacuum UV"

IKZ and Fraunhofer IPM will develop a new crystal material together

Image: Frank Kühnemann (Fraunhofer IPM), Hiroki Tanaka (IKZ), Simon Herr (Fraunhofer IPM) and Matthias Bickermann (IKZ). In front of an image of a BaMgF4 crystal grown at IKZ | © Fraunhofer IPM / Holger Kock

Over the next three years, the IKZ will develop a new crystal material together with the Fraunhofer Institute for Physical Measurement Techniques IPM in Freiburg. This material is capable of generating laser radiation in the vacuum ultraviolet (with a wavelength below 200 nm) by nonlinear frequency conversion. For this we have received funding from the Federal Ministry of Education and Research (BMBF) as part of the "Photonics and Quantum Technologies" initiative [1]. The corresponding project plan has now been presented at the kick-off meeting in Freiburg.

Continuous wave lasers with wavelengths below 190 nm are unavailable to date. They are needed for important quantum technological and metrological applications, e.g. for even more precise atomic clocks, ionic qubits for quantum computing, detection of optical transitions, and high-resolution inspection in semiconductor wafers. In the project, the IKZ will prepare high-purity and extremely low-defect BaMgF₄ crystals and prepare thin plates from them, which will then be periodically poled with high precision at the Fraunhofer IPM using a method developed there [2].  The use of such periodically poled fluoride nonlinear crystals, so-called quasi phase matching,  is the only way to achieve second harmonic generation into the vacuum ultraviolet. However, this has not yet been shown experimentally. The project partners will develop the key technologies and demonstrate the generation of radiation in the target wavelength range. The availability of such coherent light sources will lead to new and improved application-relevant quantum technologies as well as structuring and characterization methods that can open up new markets. A highly desired application is the precise excitation of ²²⁹Th nuclei at 148 nm for a new “nuclear” atomic clock that is several orders of magnitude more precise than the existing ones [3].

• [1] https://www.quantentechnologien.de/forschung/foerderung/wissenschaftliche-vorprojekte-wivopro-photonik-und-quantentechnologien/uv-krisp.html
• [2] S.J. Herr, H. Tanaka, I. Breunig, M. Bickermann, F. Kühnemann, “Fanout Periodic Poling of BaMgF₄ Crystals”, Opt. Mater. Express 13 (2023) 2158-2164. https://doi.org/10.1364/OME.492170
• [3] https://thoriumclock.eu/ , https://nuquant.physik.uni-mainz.de/

Kontakt: