Quantum interference metrology with ultrafast phase-controlled laser pulses
Dr. Kjeld S.E. Eikema (Vrije Universiteit, Amsterdam)

Modelocked lasers acting as frequency combs have revolutionized the field of optical precision metrology in the past few years. In Amsterdam we are working on extending the range of frequency combs to extreme ultraviolet wavelengths for fundamental tests (e.g. testing QED) on helium and hydrogen-like ions. The principle is based on exciting a transition by using an amplified and frequency converted train of pulses from a frequency comb. By maintaining an exact phase relationship between subsequent pulses it is possible to perform accurate spectroscopy at extreme wavelengths, although the individual pulses have a broad bandwidth. This is demonstrated with an experiment performed on a two-photon transition (2x212 nm) in krypton.