arXiv subjects

Tilman Esslinger

Publications and source records attributed to Tilman Esslinger.

114 records · Page 7Linked to original sources

arXiv2001

Measuring the temporal coherence of an atom laser beam

We report on the measurement of the temporal coherence of an atom laser beam extracted from a $^{87}$Rb Bose-Einstein condensate. Reflecting the beam from a potential barrier creates a standing matter wave structure. From the contrast of this interference pattern, observed by magnetic resonance imaging, we have deduced an energy width of the atom laser beam which is Fourier limited by the duration of output coupling. This gives an upper limit for temporal phase fluctuations in the Bose-Einstein condensate.

cond-mat↗

arXiv2001

Exploring phase coherence in a 2D lattice of Bose-Einstein condensates

Bose-Einstein condensates of rubidium atoms are stored in a two-dimensional periodic dipole force potential, formed by a pair of standing wave laser fields. The resulting potential consists of a lattice of tightly confining tubes, each filled with a 1D quantum gas. Tunnel-coupling between neighboring tubes is controlled by the intensity of the laser fields. By observing the interference pattern of atoms released from more than 3000 individual lattice tubes the phase coherence of the coupled quantum gases is studied. The lifetime of the condensate in the lattice and the dependence of the interference pattern on the lattice configuration are investigated.

cond-mat.soft↗

arXiv2001

Optics with an Atom Laser Beam

We report on the atom optical manipulation of an atom laser beam. Reflection, focusing and its storage in a resonator are demonstrated. Precise and versatile mechanical control over an atom laser beam propagating in an inhomogeneous magnetic field is achieved by optically inducing spin-flips between atomic ground states with different magnetic moment. The magnetic force acting on the atoms can thereby be effectively switched on and off. The surface of the atom optical element is determined by the resonance condition for the spin-flip in the inhomogeneous magnetic field. A mirror reflectivity of more than 98% is measured.

cond-mat↗

arXiv1998

An Atom Laser with a cw Output Coupler

We demonstrate a continuous output coupler for magnetically trapped atoms. Over a period of up to 100 ms a collimated and monoenergetic beam of atoms is continuously extracted from a Bose- Einstein condensate. The intensity and kinetic energy of the output beam of this atom laser are controlled by a weak rf-field that induces spin flips between trapped and untrapped states. Furthermore, the output coupler is used to perform a spectroscopic measurement of the condensate, which reveals the spatial distribution of the magnetically trapped condensate and allows manipulation of the condensate on a micrometer scale.

cond-mat↗

arXiv1996

Band Population Measurements in a Purely Optical Dark Lattice

We create a dark optical lattice structure using a blue detuned laser field coupling an atomic ground state of total angular momentum F simultaneously to two excited states with angular momenta F and F-1, or F and F+1. The atoms are trapped at locations of purely circular polarization. The cooling process efficiently accumulates almost half of the atomic population in the lowest energy band which is only weakly coupled to the light field. The populations of the two lowest energy bands reaches 70%. Kinetic energies on the order of the recoil energy are obtained by adiabatically reducing the optical potential. The band populations are directly mapped on free particle momentum intervals by this adiabatic release. In an experiment with subrecoil momentum resolution we measure the band populations and find good absolute agreement with the theoretically calculated steady state band populations.

physics.atom-ph↗

arXiv1996

Ramsey type Sub-Recoil Cooling

We experimentally study the motion of atoms interacting with a periodically pulsed near resonant standing wave. For discrete pulse frequencies we observe a comb-like momentum distribution. The peaks have widths of 0.3 recoil momenta and a spacing which is an integer multiple of the recoil momentum. The atomic population is trapped in ground states which periodically evolve to dark states each time the standing wave is switched on.

physics.atom-ph↗