The project is aimed at the creation and manipulation of atomic density patterns by contact-free self-assembly due to optomechanical forces. We are looking at large patches (samples size of some millimetres) of laser cooled matter (around 100 µK), which will be structured on scales of wavelengths to hundreds of micrometres. The spatial structure is not imposed externally but evolves spontaneously from an instability of the homogeneous atomic cloud in interaction with a homogeneous light field.

Atoms will start to move in the dipole force field created by spatial fluctuations in the light field, bunch together and leave voids behind. The resulting inhomogeneous atomic density distribution will serve as a grating which scatters the light and this amplifies the original fluctuation of the light field leading to a sustained spatial pattern in both light and matter. The group recently developed the theory and has obtained first experimental evidence for the spontaneous formation of hexagonal structures (see image) in collaboration with the Institut Non Lineaire de Nice.

The focus of the work is experimental but there is the exciting possibility to engage in theory, if desired.