Quantum reflection of atoms from a periodic dipole potential

Quantum reflection of neutral atoms from a periodic far-detuned dipole potential is proposed and analyzed. This periodic atom mirror relies on constructive interference of small reflections from each cell to yield a high reflection coefficient even for very weak potentials. The reflected energy spectrum is calculated as a function of the potential height and the number of cells for both positive and negative potentials, and its relation to the reflection from one potential cell is derived. Two ways of increasing the reflection bandwidth, one based on changing the envelope of the potential and the other on changing its period gradually (chirp), are investigated. The phase of the reflected atoms and its dependence on experimental parameters are calculated, as well as the interaction time of the atoms with the potential and the spontaneous-emission rate during the reflection. Finally, it is shown that atoms with velocities of a few tens mm/s can be coherently reflected from a negative periodic potential with readily available laser diodes.