Photoassociation of cold metastable helium atoms

Abstract

During the last decades the study of cold atoms has grown in a great measure. Research in this field has been made possible due to the development of laser cooling and trapping techniques. We use laser cooling to cool helium atoms down to a temperature of 1 mK and we are able to trap 106 atoms in our magneto-optical trap. The helium atoms are in a metastable state, the He 23S1 state, which has a lifetime of more than 2 hours. With cold atoms phenomena can be studied that are not accessible using thermal atoms, such as high resolution spectroscopy. Furthermore cold atoms are the first step towards Bose-Einstein condensation. Cold alkali-metal atoms have been extensively studied, using photoassociation spectroscopy. In this thesis the first photoassociation results for rare gas atoms, namely metastable helium atoms will be discussed. Various experiments are described and an analysis of the results is given.