Frequency comb laser spectroscopy at vacuum-ultraviolet wavelengths and beyond

An alternative technique for precision spectroscopy, that is rapidly gaining interest, is direct excitation of atomic transitions with a train of pulses from a frequency comb laser. As the high peak intensity of such ultrashort pulses allows efficient upconversion of an infrared frequency comb output to higher frequencies, it seems very promising for extending high-resolution spectroscopy to the VUV and XUV spectral region.