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 yi eld a high reflection coefficient even for very weak potentials. The r eflected energy spectrum is calculated as a function of the potential height and the number of cells for both positive and negative potentia ls, and its relation to the reflection from one potential cell is deri ved. Two ways of increasing the reflection bandwidth, one based on cha nging the envelope of the potential and the other on changing its peri od gradually (chirp), are investigated. The phase of the reflected ato ms and its dependence on experimental parameters are calculated, as we ll as the interaction time of the atoms with the potential and the spo ntaneous-emission rate during the reflection. Finally, it is shown tha t atoms with velocities of a few tens mm/s can be coherently reflected from a negative periodic potential with readily available laser diode s. (C) 1998 Optical Society of America.