**Figure 4.** Reflectivity in the presence of the oscillation for ω = 0.5 ω_{in}. The reflectivity for the central peak *R*_{0} and the two side peaks *R*_{−1} and *R*_{1} is shown, together with the reflectivity for the non-oscillating surface for comparison (dashed line). To calculate the *R*_{−1}, *R*_{0} and *R*_{1}, 60 calculations between two subsequent maxima in the reflectivity as a function of *x*_{0} were carried out in the range 3.7 **×** 10^{−10} m < *x*_{0} < 7.3 **×** 10^{−10} m for each velocity. Inset: reflectivity for the non-oscillating surface (dashed line) and total reflectivity *R*_{tot} for the oscillating surface (filled circles).

**Abstract**

We describe an experimentally realistic situation of the quantum reflection of helium atoms from an oscillating surface. The temporal modulation of the potential induces clear sidebands in the reflection probability as a function of momentum. These sidebands could be exploited to slow down atoms and molecules in the experiment.