No Arabic abstract
We demonstrate the possibility of trapping about one hundred million rubidium atoms in a magneto-optical trap with several of the beams passing through a transparent atom chip mounted on a vacuum cell wall. The chip is made of a gold microcircuit deposited on a silicon carbide substrate, with favorable thermal conductivity. We show how a retro-reflected configuration can efficiently address the chip birefringence issues, allowing atom trapping at arbitrary distances from the chip. We also demonstrate detection through the chip, granting a large numerical aperture. This configuration is compared to other atom chip devices, and some possible applications are discussed.
We describe experiments on trapping of atoms in microscopic magneto-optical traps on an optically transparent permanent-magnet atom chip. The chip is made of magnetically hard ferrite-garnet material deposited on a dielectric substrate. The confining magnetic fields are produced by miniature magnetized patterns recorded in the film by magneto-optical techniques. We trap Rb atoms on these structures by applying three crossed pairs of counter-propagating laser beams in the conventional magneto-optical trapping (MOT) geometry. We demonstrate the flexibility of the concept in creation and in-situ modification of the trapping geometries through several experiments.
A diffractive optical element (DOE) has been fabricated for creating blue detuned atomic bottle beam traps. The DOE integrates several diffractive lenses for trap creation and imaging of atomic fluorescence. We characterize the performance of the DOE and demonstrate trapping of cold Cesium atoms inside a bottle beam.
Laser cooling and trapping are central to modern atomic physics. The workhorse technique in cold-atom physics is the magneto-optical trap (MOT), which combines laser cooling with a restoring force from radiation pressure. For a variety of atomic species, MOTs can capture and cool large numbers of particles to ultracold temperatures (<1 mK); this has enabled the study of a wide range of phenomena from optical clocks to ultracold collisions whilst also serving as the ubiquitous starting point for further cooling into the regime of quantum degeneracy. Magneto-optical trapping of molecules could provide a similarly powerful starting point for the study and manipulation of ultracold molecular gases. Here, we demonstrate three-dimensional magneto-optical trapping of a diatomic molecule, strontium monofluoride (SrF), at a temperature of approximately 2.5 mK. This method is expected to be viable for a significant number of diatomic species. Such chemical diversity is desired for the wide array of existing and proposed experiments which employ molecules for applications ranging from precision measurement, to quantum simulation and quantum information, to ultracold chemistry.
We report the laser-cooling and confinement of Cd atoms in a magneto-optical trap, and characterize the loading process from the background Cd vapor. The trapping laser drives the 1S0-1P1 transition at 229 nm in this two-electron atom and also photoionizes atoms directly from the 1P1 state. This photoionization overwhelms the other loss mechanisms and allows a direct measurement of the photoionization cross section, which we measure to be 2(1)x10^(-16)cm^(2) from the 1P1 state. When combined with nearby laser-cooled and trapped Cd^(+) ions, this apparatus could facilitate studies in ultracold interactions between atoms and ions.
We present experimental results from a new scheme for magneto-optically trapping strontium monofluoride (SrF) molecules, which provides increased confinement compared to our original work. The improved trap employs a new approach to magneto-optical trapping presented by M. Tarbutt, emph{arXiv preprint} 1409.0244, which provided insight for the first time into the source of the restoring force in magneto-optical traps (MOTs) where the cycling transition includes dark Zeeman sublevels (known as type-II MOTs). We measure a radial spring constant $20times$ greater than in our original work with SrF, comparable to the spring constants reported in atomic type-II MOTs. We achieve a trap lifetime $tau_{rm{MOT}}=136(2)$~ms, over $2times$ longer than originally reported for SrF. Finally, we demonstrate further cooling of the trapped molecules by briefly increasing the trapping lasers detunings. Our trapping scheme remains a straightforward extension of atomic techniques and marks a step towards the direct production of large, dense, ultracold molecular gases via laser cooling.