Electrically controlled quantum reflection

We demonstrate experimentally that an electric field can be used to control quantum reflection of matter waves off periodically microstructured surfaces. Applying a voltage of alternating polarity between neighboring grating bars induces an electric field which modifies the interaction between the surface and the impinging matter wave so that quantum reflection is gradually reduced. We find that the measured reflectivities are in good agreement with our numerical simulations and that their suppression is well captured by a simple analytic model. This experiment constitutes a step towards electrically tuned reflective diffraction elements for atomic and molecular matter waves.