Cold atoms in optical cavities: Bloch Oscillations & Band-Structure Loops
McMaster University, Hamilton,Canada.
The dispersive interaction of cold atoms with laser light in free space has been exploited to make optical lattice-cold atom systems that are ultra clean and controllable analogs of electrons in ionic lattice potentials. When such a laser light field is replaced by the single mode light field inside a high quality factor cavity, the resulting coupled light atom system can show very interesting behaviour due to the back action of the atoms on the light field, which can be large inside a cavity unlike free space. In our work we dealt with one dynamical and one static effect in this system. When a uniform force is applied on a particle in a periodic potential, the resulting dynamics is periodic and is known as Bloch Oscillations. In the first part of the talk I will focus upon Bloch Oscillations of a particle in a periodic cavity field and a novel non-destructive measurement technique for the Bloch frequency of the oscillation. The energy dispersion for a particle in a periodic potential is arranged into energy bands. When the particle (atoms) can back act on the periodic potential (cavity light field), even though the periodicity of the potential is not affected, the non-linear atom-light interaction can give rise to very interesting loops in the band structure diagram that can be related to other interesting effects like bistability in transmission intensity of the cavity. This will be the subject of the second part of the talk.