Laser Focusing And Electrostatic Guiding Of Neutral Molecules

In recent years, cold molecules with rich internal level structure have opened up some new opportunities for molecular precision spectroscopy and measurements, studies of cold molecular collisions, quantum information processing and so on. The study of generation and application of cold molecules has obtained many fast development and important progress. In this thesis, the principle, experiment and recent progress on cooling, trapping and manipulating of neutral molecules have been first briefly introduced and reviewed. Secondly, generation of a focused hollow beam by a 2Ï€-phase plate has been proposed, and discuss its application in atom or molecule optics. Afterwards, electrostatic guiding of neutral molecules is studied in detail theoretically and experimentally. In final, our research work is summarized and the future investigation is briefly looked ahead.We study a new scheme to generate a focusing hollow beam (FHB). From the Fresnel diffraction theory, we calculate the intensity distributions of the FHB in free propagation space, Since this kind of hollow beam has a very small dark spot size (DSS) in the focal plane, it can be used to focus atomic (or molecular) beam as an atomic (or molecular) lens, even to study adiabatic heating and cooling of atoms (molecules) in the blue-detuned FHB due to adiabatic compression and expansion of guided atomic (or molecular) beam. Our study shows that the FHB can be used to cool and trap neutral atoms by intensity-gradient induced Sisyphus cooling due to extremely high intensity gradient of the FHB itself near the focal point, or to guide and focus cold molecular beam. We also calculate the optical potential of theblue-detuned FHB for ⁸⁵Rb atoms and found that in the focal plane, the smaller the dark spot size of the FHB, the higher the optical potential, and the greater the corresponding optimal detuning 6, which are beneficial to atomic lens because it cannot only be profitable to obtain an atomic lens with a higher resolution, but also helpful to reduce the spontaneous photon-scattering effect of atoms in the FHB. We propose a novel scheme to guide cold polar molecules on the surface of an...