Using a lens for matter waves in an atom interferometer

We demonstrate the use of a lens for matter waves that increased our interference fringe contrast from 16{\%} to 24{\%}. To create our lens, we used a static electric field gradient inside our three nanograting Mach-Zehnder atom interferometer. We discovered that our lens (f = -500m) can compensate for misalignments, such as imperfect grating period. We explore how the (de)focusing effect can influence our precision measurements of atomic polarizability, and how such a lens can be useful in other layouts such as a Talbot Lau interferometer. We gratefully acknowledge NSF support for this work.