Quantum optics with thermal atomic vapours.

Many of the work-horse techniques of contemporary atomic physics experiments were first demonstrated in hot atomic vapours. These media are ideally suited for quantum-optics experiments as they combine strong atom-light interactions, with long coherence times, and well-understood and characterised atom-atom interaction.
In the burgeoning field of quantum information and technology there are two potentially rich areas of using atomic vapours: as sources of single photons, and as narrowband filters to eliminate unwanted source of radiation.
The key objectives of this research project are to understand, characterize numerically and measure experimentally the filtering properties of an atomic medium, in the context of quantum optics experiments. Previous work in Durham has shown that adding a large magnetic field dramatically simplifies the theoretical modelling of the medium. One of the big questions we shall address in this investigation is whether the simplification of the energy-level structure leads to higher figures of merit when realising experimental ultranarrow filters. Previous work in the literature has tended to concentrate on the qualitative understanding of the lineshape of the atom-light interaction; by contrast, in this work, the novel aspect of our methodology will be to use statistical techniques to compare the quantitative agreement of our theoretical and numerical calculations with the optical properties of the medium comprising a thermal atomic vapour. The student will calculate numerically the expected values of the Stokes parameters (that characterise atom-light interactions in the presence of a magnetic field) for different atomic cells, fields and temperatures; this shall be followed by quantitative theory-experiment comparisons; finally building on the understanding gained the optimal properties of optical devices shall be ascertained and verified experimentally.