Magneto-optical trapping and background-free imaging for atoms near nanostructured surfaces

Abstract

Abstract:We demonstrate a combined magneto-optical trap and imaging system that is suitable for the investigation of cold atoms near surfaces. In particular, we are able to trap atoms close to optically scattering surfaces and to image them with an excellent signal-to-noise ratio. We also demonstrate a simple magneto-optical atom cloud launching method. We anticipate that this system will be useful for a range of experimental studies of novel atom-surface interactions and atom trap miniaturization.

Magneto-optical trapping and detection of atoms through a transparent atom chip

“…With a saturation intensity of 4.1 mW/cm², this leads to an estimated 1.1 x 10 8 atoms in the MOT according to [5]. This is comparable to what was obtained in our similar, earlier setup without the chip, and it also stands the comparison to other near-surface MOT techniques [1,2,6,7].…”

Trapping of85Rb atoms by optical pumping between metastable hyperfine states

“…All beams along the trapping axis of the MOP trap were linearly polarised to eliminate magneto-optical forces in this direction. Around 10 4 85 Rb atoms were captured -about a third of the number obtained with a full 3-D MOT in this configuration [10]. The trapped atom cloud is shown in figure 3(a).…”

Amplified spontaneous emission at 523 μm in two-photon excited rubidium vapor

“…This is largely because of the difficulty of detecting the mid-IR radiation, which is strongly absorbed in conventional Rb cells. We note that similar energy level configurations in Rb atoms have been used extensively for studying ladder-type electromagnetically induced transparency [15,16], nonlinear properties of four-wave mixing and new field generation [17,18], atomic coherence effects [19,20] and transfer of orbital angular momentum [3,21], as well as for imaging of ultracold atoms [22].…”