Study Of Electrostatic Stark Deceleration And Splitting For A Polar Molecular Beam On A Chip

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 and quantum information as well as many other aspects, which lead to the rapid development of the generation and applications of cold or ultra cold molecules. In this thesis, we first summarize cold and ultraclod molecule's fundamental science, the methods to produce cold and ultraclod molecules, as well as its application and new directions. Secondly, we propose a scheme of decledrating molecules on a chip using electrostatic fields together with a blue-detuned dark hollow laser beam. Thirdly, we carry out experimental study of splitting molecular beams on the surface of a substrate. Finally, a summary of my work over the years along with an outlook for future research is given.We expound the scheme of a Stark decelerator on a chip. First, we calculate the electrical field distribution in the decelerator using the software of Maxwell. Then, the Stark potential of weak-field-seeding ND3 molecules and their corresponding electrical dipolar gradient force inside the decelerator are analyzed. We also perform a Monte-Carlo simulation of the dynamics of ND3 molecules through the decelerator. Our result shows that ND3 molecules of 370 m/s can be slowed to a final velocity of 228 m/s after passing the 5cm-long electrode array. To reduce the transverse loss of molecules a blue-detuned dark hollow laser beam can be introduced. Due to the transverse confinement of the laser beam, the number of slowed molecules can be greatly ehanced.We carry out experimental study of splitting molecular beams on the surface of a substrate. First, we study the relation between the translational temperature of the molecular beam and the temperature of the beam source chamber; second, we study the dependence of the splitting ratio on the voltage differcen of the two output arms, and experimental results agree well with those obtained from Monte-Carlo simulatons.