Magnetostatic Focusing Of Cold Atomic Beams And Its Magnetic Lens On Atom Chip

In this thesis, the research background of atomic lens and its latest development are first reviewed. The focusing of neutral atoms relies on the interaction of various fields with neutral atoms. Different schemes of atomic lens and their properties as well as their basic principles are classified and briefly introduced, and perform detail comparison fro different atomic lens. Then some potential applications of atomic lens in the atomic microscopy, atomic microprobe, atom lithography as well as fabrication of grating are discussed. In addition, recent experimental studies and progresses are also briefly introduced.We propose two novel schemes to construct single magnetic lens and arrays of magnetic lenses. One is composed of a square wire loop, which is formed by four L-shaped current-carrying wires, and its lens array is composed of an array of square current-carrying wires. For the special arrangement of currents in the square wire loop, there exists a quadrupole field in the vicinity of the wire loop, which is similar to the magnetic-field distribution formed by a permanent quadrupole magnet. We find that the general function of atomic lens could be achieved by using our lens scheme from theoretical analysis and calculation. We perform Monte-Carlo simulations and trajectory tracing method to study the dynamic process of atomic-beam focusing when the atomic cloud of rubidium-87 passes through a single magnetic micro-lens or a 2D array of magnetic micro-lenses. Our result shows that cold atoms can be focused effectively by our scheme, and the focal length of the atomic lens and its radius of focused spot can be continuously changed by adjusting the current in the wires.Another lens scheme is constructed by a circular wire loop. First the magnetic field strength and its gradient distribution are calculated, and the results show that single circular wire loop can be used to built a micro-lens. We also simulate the focusing process of a cold atomic beam by single wire loop. Then we extend our single circular wire loop to one-dimensional and two-dimensional array of magnetic micro-lenses. We calculate their magnetic field and its gradient distributions, and simulate the focusing...