Design Of An Atom Chip System For Single-Atom Trapping

Because of the bright prospect for high-speed information processing, quantum information technology has become the hottest research topic in recent years. Among the promising candidates for quantum computation, the single-atom system is an outstanding one for its long coherence time, high controllability and high scalability. Atom chips integrated with high-precision atom control devices are the best platform for practicability and miniaturization of cold atom experiments. A basic model for quantum computer can be offered by the combination of atom chips and single-atom system.This thesis summarizes the design of an atom chip system for single-atom trapping. The core component of the system is an atom chip which integrates micro lens waveguide on it. The core component around which the system is developed consists of two parts:an two-atom-chip assembly and a ribbon waveguide with micro lens on its end face.The two-atom-chip assembly contains two atom chips, a small one and a large one. Main work of the assembly is to trap and convey cold atoms. Key points of the design are wire layout, substrate materials and manufacturing process. The two-chip design enable the two atom chips to meet different requirements:high mechanical strength, heavy carrying current and thermal conductivity match with the vacuum chamber for the large one and high reflectivity, high thermal conductivity and light carrying current for the small one. Simulation results show that our design meet the requirement of transforming the atoms.The micro-lens-integrated ribbon waveguide is used to transmit the laser and trap a single atom. No crosstalk between neighbour channels is the most important requirement for waveguide design. These are achieved by adjusting dimension and reflectivity of the waveguide. Simulation results show that there is no crosstalk between the10μm-spacing cores when the cross section of the cores are4μm*4μm and reflectivity difference of core and cladding is0.75%.The micro lenes focus the laser and create dipole traps. The radius of curvature of micro lens is the key point in design. With computer simulation, we find that focal length of the micro lens should be set between10μm and20μm which is fit for trapping a single atom.