High Resolution Electron Microscopy of Quantum Gases

The complete understanding of the properties of ultracold and degenerate samples requires the ability to probe and manipulate such systems with extremely high resolution and precision. The introduction of the scanning electron microscopy (SEM) techniques on ultracold atoms provides the necessary tool for such purposes, thus allowing the observation of several fundamental phenomena with unprecedented clarity. Thanks to its extremely high resolution (<100 nm) and to the single-atom sensitivity the SEM method permitted the first observation of in situ profiles of trapped Bose-Einstein condensates of⁸⁷Rb and of ultracold clouds in one- and two-dimensional optical lattices. Moreover the single lattice sites were selectively addressed and manipulated thus demonstrating the possibility to create arbitrary patterns of occupied sites. In addition to the spatial characteristics of ultracold samples the SEM technique allows for the investigation of their dynamical processes. Moreover, exploiting the single atom sensitivity of the method, second and higher order correlation functions can be measured as well.