arXiv subjects

A. Guenther

Publications and source records attributed to A. Guenther.

6 recordsLinked to original sources

arXiv2013

Trapping of ultra cold atoms in a 3He/4He dilution refrigerator

We describe the preparation of ultra cold atomic clouds in a dilution refrigerator. The closed cycle 3He/4He cryostat was custom made to provide optical access for laser cooling, optical manipulation and detection of atoms. We show that the cryostat meets the requirements for cold atom experiments, specifically in terms of operating a magneto-optical trap, magnetic traps and magnetic transport under ultra high vacuum conditions. The presented system is a step towards the creation of a quantum hybrid system combining ultra cold atoms and solid state quantum devices.

physics.atom-ph↗

arXiv2005

Combined chips for atom-optics

We present experiments with Bose-Einstein condensates on a combined atom chip. The combined structure consists of a large-scale "carrier chip" and smaller "atom-optics chips", containing micron-sized elements. This allows us to work with condensates very close to chip surfaces without suffering from fragmentation or losses due to thermally driven spin flips. Precise three-dimensional positioning and transport with constant trap frequencies are described. Bose-Einstein condensates were manipulated with submicron accuracy above atom-optics chips. As an application of atom chips, a direction sensitive magnetic field microscope is demonstrated.

cond-mat.other↗

arXiv2005

Diffraction of a Bose-Einstein condensate from a Magnetic Lattice on a Micro Chip

We experimentally study the diffraction of a Bose-Einstein condensate from a magnetic lattice, realized by a set of 372 parallel gold conductors which are micro fabricated on a silicon substrate. The conductors generate a periodic potential for the atoms with a lattice constant of 4 microns. After exposing the condensate to the lattice for several milliseconds we observe diffraction up to 5th order by standard time of flight imaging techniques. The experimental data can be quantitatively interpreted with a simple phase imprinting model. The demonstrated diffraction grating offers promising perspectives for the construction of an integrated atom interferometer.

cond-mat.other↗

arXiv2005

Atom-optical elements on micro chips

We describe the realization of atom-optical elements as magnetic waveguide potentials, beam splitters and gravitational traps on a microchip. The microchip was produced by electroplating gold conductors on an aluminium-oxide substrate. The conductors are 30-150 $μ$m wide and allow for the generation of waveguides at large distances to the chip surface, where surface effects are negligible. We show that these elements can be integrated on a single chip to achieve complex atom-optical circuits.

cond-mat.other↗

arXiv2002

Bose-Einstein Condensates in Magnetic Waveguides

In this article, we describe an experimental system for generating Bose-Einstein condensates and controlling the shape and motion of the condensate by using miniaturised magnetic potentials. In particular, we describe the magnetic trap setup, the vacuum system, the use of dispenser sources for loading a high number of atoms into the magneto-optical trap, the magnetic transfer of atoms into the microtrap, and the experimental cycle for generating Bose-Einstein condensates. We present first results on outcoupling of condensates into a magnetic waveguide and discuss influences of the trap surface on the ultracold ensembles.

cond-mat.soft↗

arXiv2002

Anomalous Longitudinal Magnetic Field near the Surface of Copper Conductors

We have used ultracold atoms to characterize the magnetic field near the surface of copper conductors at room temperature carrying currents between 0.045 A and 2 A. In addition to the usual circular field we find an additional, 1000 - 10000 times smaller longitudinal field. The field changes its strength periodically with a period of 200-300 um.

cond-mat.soft↗