2D Optical Trapping Potential for the Confinement of Heteronuclear Molecules

Abstract

Polar ultracold molecules such as the ground state alkali-metal dimers are interesting to study due to their long range dipole-dipole interaction. Such molecules have been produced and trapped within an optical trap formed by high power laser beam. This trapping method, however, leads to a high peak molecule density and suffers from a short lifetime due to the enhanced chemical-reaction loss. It has been shown that this loss could be reduced by shaping the trap beam into a periodic 2-dimensional flat-top beam which reduces the peak density while maintaining a strong trapping potential. In this thesis, we present a study to realize the beam shaping of a Gaussian laser beam into a flat-top beam using a tilt-mirror-array type spatial light modulator (SLM). An algorithm designing the SLM pattern is tested numerically and compared with experimental observation. Furthermore, we construct a feedback algorithms improving the SLM pattern according to the real-time measured beam profile.