We have integrated magneto-optical traps (MOTs) into an atom chip by etching pyramids into a silicon wafer. These have been used to trap atoms on the chip, directly from a room temperature vapor of rubidium. This new atom trapping method provides a simple way to integrate several atom sources on the same chip. It represents a substantial advance in atom chip technology and offers new possibilities for atom chip applications such as integrated single atom or photon sources and molecules on a chip.

The temperature dependence of the Casimir–Polder interaction addresses fundamental issues for understanding vacuum and thermal fluctuations. It is highly sensitive to surface waves, which, in the near field, govern the thermal emission of a hot surface. Here we use optical reflection spectroscopy to monitor the atom–surface interaction potential between a Cs*(7D_3/2) atom and a hot sapphire surface at distances of ~100 nm. In our experiments, that explore a large range of temperatures (500–1,000 K), the surface is at thermal equilibrium with the vacuum. The observed increase of the interaction with temperature, by up to 50%, relies on the coupling between atomic virtual transitions in the infrared range and thermally excited surface-polariton modes. We extrapolate our findings to a broad distance range, from the isolated atom to the short distances relevant to physical chemistry. Our work also opens the prospect of controlling atom–surface interactions by engineering thermal fields.

An atom in front of a surface is one of the simplest and fundamental problem in physics. Yet, it allows testing quantum electrodynamics, while providing potential platforms and interfaces for quantum technologies. Despite its simplicity, combined with strong scientific and technological interests, atom-surface physics, at its fundamental level, remains largely unexplored mainly because of challenges associated with precise control of the atom-surface distance. Nevertheless, substantial breakthroughs have been made over the last two decades. With the development of cold and quantum atomic gases, one has gained further control on atom-surface position, naturally leading to improved precision in the Casimir–Polder interaction measurement. Advances have also been reported in finding experimental knobs to tune and even reverse the Casimir–Polder interaction strength. So far, this has only been achieved for atoms in short-lived excited states, however, the rapid progresses in material sciences, e.g., metamaterials and topological materials has inspired new ideas for controlling the atom-surface interaction in long-lived states. In addition, combining nano-photonic and atom-surface physics is now envisioned for applications in quantum information processing. The first purpose of this Review is to give a general overview on the latest experimental developments in atom-surface physics. The second main objective is to sketch a vision of the future of the field, mainly inspired by the abundant theoretical works and proposals available now in the literature.

We take a closer look at the fundamental Casimir-Polder (CP) interaction between quantum particles and dispersive dielectric surfaces with surface polariton or plasmon resonances. Linear response theory shows that in the near-field, van der Waals regime the free-energy shift of a particle contains a thermal component that depends exclusively on the excitation of the evanescent surface polariton (plasmon or phonon) modes. Our work makes evident the link between particle surface interaction and near-field thermal emission and demonstrates how this can be used to engineer Casimir-Polder forces. We also examine how the exotic effects of surface waves are washed out as the distance from the surface increases. In the case of molecules or excited-state atoms, far-field approximations result in a classical dipole-dipole interaction which depends on the surface reflectivity and the mean number of photons at the frequency of the atomic or molecular transition. Finally we present numerical results for the CP interaction between Cs atoms and various dielectric surfaces with a single polariton resonance and discuss the implications of temperature and retardation effects for specific spectroscopic experiments.

Spectroscopy is a unique experimental tool for measuring the fundamental Casimir-Polder interaction between excited-state atoms, or other polarizable quantum objects, and a macroscopic surface. Spectroscopic measurements probe atoms at nanometric distances away from the surface where QED retardation is usually negligible and the atom-surface interaction is proportional to the inverse cube of the separation distance, otherwise known as the van der Waals regime. Here we focus on selective reflection, one of the main spectroscopic probes of Casimir-Polder interactions. We calculate selective reflection spectra using the full, distance dependent, Casimir-Polder energy shift and linewidth. We demonstrate that retardation can have significant effects, in particular for experiments with low-lying energy states. We also show that the effective probing depth of selective reflection spectroscopy depends on the transition linewidth. Our analysis allows us to calculate selective reflection spectra with composite surfaces, such as metasurfaces, dielectric stacks, or even bidimensional materials.