News: Our latest work on injection locking and the detection of ultra-weak forces has been highlighted as Editors' Suggestion in Physical Review Letters. More.

Welcome to the ion trapping project

We are part of Prof. T.W. Hänsch's Group and located at the Max-Planck-Institute of Quantum Optics in Garching near Munich, Germany.

Established in 2004, our long-term goals are to perform precision tests of one of the corner stones of the standard model - quantum electrodynamics (QED) - by means of high precision laser spectroscopy of single trapped ions. Our main targets are the 1s-2s two-photon transition in He+ at 60.8 nm (bound-state QED of one electron) and several transitions in metastable Li+ (bound-state QED of two electrons).

Meanwhile, the scope of our research has broadened to the following areas:
In one project we explored how accurately one can perform precision spectroscopy of strong (dipole) transitions in single trapped ions. The vast majority of precision metrology experiments on trapped ions so far focused on weak clock transitions. However, accurate knowledge of dipole transitions is important for a number of fields, ranging from theoretical atomic physics to astrophysics and the quest for possible drifts of fundamental constants. For this purpose we devised a new spectrocopy technique that enables unprecedented accuracy.
In a further project we view an ion as a pristine realization of a harmonic oscillator and study the optomechanics of single trapped ions. The scattering of red detuned photons is well known to cool an ion. The complementary regime of blue detuned pumping has received far less attention and is the starting point of our investigations. In particular, we study a single trapped ion interacting with two laser beams, one tuned above and below resonance, respectively. This simple system exhibits a remarkable wealth of phenomena, in particular we were able to show that the blue detuned laser does not merely heat the ion but instead provides coherent, saturable gain for the ion's motion. A detailed analysis shows that such an optically excited, coherently oscillating ion constitutes the mechanical analogue of a laser - a phonon laser.
Recently, we were able to demonstrate injection locking of our phonon laser. Careful calibration reveals that we attained injection locking with ultra-weak forces as low as 5 yN, i.e. 5 x 10-24 N. This great sensitivity may allow the detection of the nuclear magnetic moment of single atomic or molecular ions.

September 21, 2011, at 09:08 AM