X-ray frequency comb

So far, laser combs in visible light wavelength have been known as an extremely precise measure of dimensions. What would happen if they move into the X-ray region? The advent of an X-ray free electron laser (XFEL) may realize an X-ray frequency comb in the near future. Dr. S. M. Cavalettobe (Max-Planck-Institut fur Kernphysik, Heidelberg, Germany) is proposing such an ambitious experiment. The research could open up wide-ranging applications; ultraprecise X-ray atomic clocks, determination of many X-ray fundamental parameters, quantitative understanding of astrophysical models and quantum electrodynamics etc. For more information, see the paper, "Broadband high-resolution X-ray frequency combs", S. M. Cavaletto et al, Nature Photonics, June 2014 (DOI: 10.1038/nphoton.2014.113).