Arthur Jungkind, UINN

Coupled nonlinear dynamics of atoms and optical resonator modes in new trap and pump geometries

Layman title: Light-matter interaction inside high-quality optical cavities

The application of lasers to control the motion of polarisable particles creates a new path towards cooling an atomic gas to unprecedented low temperatures. Using mirrors to build an optical resonator allows us to trap and manipulate the motion of cold particles. However, the control over the system is limited by fluctuations, which are caused for example by collisions between photons of the trapping and driving laser and the atoms. Therefore, the aim is to reduce such perturbative processes in order to increase the efficiency of controlling and manipulating particle motion and thus pave the way for further ground breaking research.

Light-matter interaction inside optical cavities has been thoroughly investigated for far red-detuned driving fields. In this regime it was found, that the atoms self-organise such that they occupy positions of high light intensity. This leads to frequent collisions with photons and therefore a steady perturbation on the atomic position and momentum. However, for far blue-detuned driving fields the particles are expected to locate at the low-intensity regions inside the optical resonator. Here, the light-matter interaction rate is strongly suppressed which leads to less noise on the system properties. This leads to a change of the cooling and trapping properties of the system and furthermore has a significant influence on the self-organisation. Hence, the aim of this project is to investigate the behavior of the coupled light-matter dynamics with respect to the various system parameters in the far blue-detuned regime for monochromatic as well as multi-colored pump fields. The results will be compared with those obtained for red-detuned pump in order to find the most promising applications of cavity cooling.

The theoretical work is done at the Institute for Theoretical Physics of the University of Innsbruck in the Cavity Quantum Electrodynamics (cavity QED) group of Prof. Helmut Ritsch (see: The collaboration with other theoretical as well as experimental groups is provided by the ColOpt network. The network allows to compare results and provides the opportunity for an experimental realization of our theoretical and numerical analysis.

The aim of the research done during the course of this project is to find ways how to create novel cavity QED setups with far blue-detuned driving fields to investigate self-organisation effects in the blue-detuned regime. The analysis of cooling and trapping mechanisms in this regime promises highly efficient and accurate possibilities to cool and trap polarisable particles. Furthermore, the outcome of this considerations will act as a guideline for future experiments, since it gives an overview of the right system parameters and geometries to choose for various quantum-optical purposes.