Towards a VUV Cw Laser Light Source

Coherent continuous-wave (cw) laser light in the vacuum-UV (VUV, < 200 nm wavelength) is needed for several quantum technological and metrological applications. One important application is the excitation and detection of optical transitions in atoms and ions. As an example, electronic transitions of the Al-ion at 167 nm wavelength are investigated for precise atomic clocks [1]. Recently, the nuclear isomeric transition of the 229Th-ion at around 150 nm wavelength has attracted much interest, as it may allow for ultra-precise, next-generation nuclear optical clocks [2]. Other VUV-wavelengths are needed for qubit applications via Rydberg-excitation, the ion-cooling for the generation of Bose-Einstein condensates or for multi-photon processes for precision spectroscopy in the hydrogen ion. In the semiconductor industry, VUV wavelengths are relevant for highly sensitive wafer inspection.