Controlling Cold Atoms using Nanofabricated Surfaces: Atom Chips

Abstract

Atoms can be trapped and guided using nanofabricated wires on surfaces, achieving the scales required by quantum information proposals. These atom chips form the basis for robust and widespread applications of cold atoms ranging from atom optics to fundamental questions in mesoscopic physics, and possibly quantum information systems.

Optimized magneto-optical trap for experiments with ultracold atoms near surfaces

“…The problem of a material object (partially) obstructing the access of the six beams used in a conventional MOT has also been circumvented by producing the MOT [12] or even the condensate [13] elsewhere and transfer it to the chip by means of dynamic magnetic fields [12] or optical tweezers [13]. The alternative is to directly load a mirror MOT [9,14,15,16] only millimeters away from a reflecting surface that acts as a mirror. In this configuration, at least one of the MOT beams is reflected off the mirror.…”

“…In this configuration, at least one of the MOT beams is reflected off the mirror. In the simple version used in many atom chip experiments [4,9,16], two of the regular six MOT beams are replaced by reflections of two beams impinging upon the mirror [18] at an angle of 45 • . To ensure the correct quadrupole field orientation with respect to the helicities of the light beam pairs, the quadrupole field axis has to coincide with one of the 45 • light beams.…”

Trapped-atom interferometer in a magnetic microtrap

“…Since the first realization of magnetic traps [1,2] and guides [3,4] with current-carrying conductors on a chip, a large variety of magnetic potentials have become experimentally accessible, which would be impractical or even impossible to realize with macroscopic coils. The splitting of two-dimensionally trapped atom clouds has been demonstrated [5,6], and recently, we were able to split and unite a three-dimensionally trapped cloud of rubidium atoms in a chip trap [7].…”

Two-wire guides and traps with vertical bias fields on atom chips

“…In the next step, the cloud is loaded to the magnetic potentials produced by wires on the chip. The details of this procedure are given in [4,16]. In order to transfer the atoms from a U-wire trap, i.e.…”

“…After the demonstration of simple magnetic trapping and guiding potentials [3,4], the production of Bose-Einstein condensates (BEC) [5,6,7,8] and the integration of electrostatic fields [9] on the chips have been important milestones on the way to a fully functional toolbox for the control of atomic matter waves. Issues currently under investigation include the integration of light elements for enhanced detection efficiency of (single) atoms [10] and the coherence properties of atoms in the chip potentials [11].…”