A New Optical Trap System for Ultracold Strontium
Killian, Thomas C.
Master of Science
Atoms can be trapped at the foci of intense laser beams, which can enable the study of interactions and dynamics of ultracold gases. In this thesis, we will describe our new trap designs. A large volume pancake-shaped optical dipole trap is initially used for loading large numbers of atoms from a Magneto-Optical Trap. A BEC with a large number of 84 Sr atoms has been achieved after evaporation in this trap. To form degenerate gas of 88 Sr we compress the mixture of 88 Sr and 87 Sr from the loading trap into a superimposed dimple trap. This combination improves the reproducibility of the experiment and shortens the time required to create quantum degenerate samples, while we are able to create 88 Sr BEC with high density. In order to generate BEC of 86 Sr, an isotope with large scattering length and extremely high three-body loss rate, we implement an optical sheet trap which has an aspect ratio of 1:10. The tight axis in the vertical direction provides strong potential to hold against gravity while the large horizontal dimension brings up the trap volume and keeps down the atomic density.
Optical dipole trap; Ultracold Strontium; Quantum degenerate gas; Atomic physics