Theoretical Study Of Electrostatic Surface Guiding For Cold Poplar Molecules

Cold molecules have some important applications in high-resolution spectroscopy and precise measurement, cold chemical reaction and cold collisions, interferometer of matter wave, and quantum computing and information possessing and so on. Recently, the study of generation, controlling, guiding and application of cold molecules has obtained fast development. In this thesis, firstly, the principle, experiment and recent progress on controlling and guiding of neutral molecules are briefly reviewed. Secondly, we perform the theoretical study on two new schemes to realize electrostatic surface guiding for cold polar molecules. Finally, our research work is summarized and some future investigations are briefly looked ahead.We propose a novel scheme to guide and funnel cold polar molecules on the surface of an insulating substrate (i.e. a molecular chip) using an electrostatic field generated by the combination of three parallel charged wires. We calculate the spatial distributions of the electric fields from the above charged-wire layout and their Stark potential for cold CO molecules, and analyze the relationships between the electric field and the geometric parameters of our charged-wire system. Also, we calculate and study the straight and bent guiding efficiency of cold polar molecules (including the guiding efficiency in our molecular funnel) by Monte Carlo simulation. Our study shows that the proposed novel charged-wire scheme can be used to realize the controllable surface guiding of cold polar molecules in the weak-field-seeking state on a chip, and form various integrated molecular optical elements, even to generate acw cold molecular beam on a chip.We also propose another controllable surface guiding scheme for cold polarmolecules by using four charged wires embedded in the substrate, and calculate the spatial distributions of the electrostatic field from our four charged-wire layout and the Stark potential for cold CO molecules. We analyze the relationships between the maximum trapping electric field (including the efficient well depth) and the system parameters, and study the straight and bent guiding efficiencies of cold polar molecules in the week-field-seeking state by using a simple theoretical model and Monte-Carlo simulation. Also, the transverse and longitudinal velocity distributions of the output guided molecular beam are simulated. Our study shows that the proposed four-wire scheme can be used to realize the manipulation and control of cold polar molecules in our surface guide on a chip and form a variety of molecule optics elements, our study have some important applications in cold chemical reaction and cold collision, interferometer of matter wave, and quantum computing and information possessing and so on.