Study Of Electrostatic Guide For Cold Polar Molecules And Photoelectric Control Techniques

Cold molecules are playing an important role in high-resolution spectroscopy, precise measurement,cold chemical reaction and cold collisions,interference of matter wave,quantum computation,quantum information and many other aspects, which lead to the rapid development of the generation and applications of cold or ultra cold molecules.In this thesis,the principle of manipulating neutral molecules,the experimental results and its recent progress are introduced in some detail.Next,we studied some significant photoelectric controlling techniques in the experiments,and designed a photoelectric isolation controlling device,which has short delay between input and output signals,to protect the experimental equipments.High voltage pulse technique is crucial in the Stark deceleration,and we calculated the rise and fall times, which is in good agreement with our experimental results.Besides,we also optimized the resistance value to make the rise time and fall time to be stable.In the main part, the theoretical and experimental research of electrostatic guiding of cold molecules is introduced.Finally,a summary of our work is given and the prospect is discussed.The most creative part of this thesis is our research on electrostatic guiding of cold CH₃CN.First,we proposed a new scheme to realize electrostatic guiding for cold poplar molecules on a substrate by a single charged wire on a substrate and a grounded metal plate.When a positive voltage is applied on the wire,ta hollow electrostatic tube will be produced above the substrate.Next,we made a Monte-Carlo simulation of guiding cold CH₃CN and calculated its guiding efficiency.Finally,we performed the experimental research on electrostatic guiding of cold CH₃CN, including the experimental set up and recent progress in our experiment.We also studied the transverse velocity and longitudinal velocity distributions of the molecular beam.Moreover,we estimated the transverse and longitudinal temperatures of supersonic molecular beam from our experimental results,which are in good agreement with the corresponding theoretical predictions.