Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2006.Includes bibliographical references (p. 105-114).This thesis describes experiments with ion traps constructed with electrodes in a single two-dimensional plane, and ion traps operated in a cryogenic environment at 77K and 4K temperatures. These two technologies address needs which arise in developing potentially scalable approaches to quantum computing using trapped ions. Traps with electrodes in a plane are challenging to load because their trap depths are usually only of order one percent that of multi-level traps of comparable dimensions. In addition, ion heating rates in these traps are higher than in multi-level traps because of the close proximity of the electrodes that is required to achieve a reasonable trap depth and the relatively resistive semiconductor electrode materials used in planar traps fabricated with standard semiconductor lithography methods. We investigate planar traps using macroscopic ions, focusing on devising techniques for loading these shallow traps and designing electrode layouts for ion movement. Using traps fabricated lithographically with copper traces on fiberglass laminate, we trap linear chains of tens of charged particles of [approx.] 400nm diameter in a rough vacuum of 15 Pa.(cont.) We perform experiments to address concerns about the low trap depth of planar ion traps and develop control electrode layouts for moving ions between trap zones. Motivated by the desire to lower the heating rates in planar traps, we design and implement an experiment trapping strontium-88 ions in a knife-edge trap in a helium cryostat. The design challenges are obtaining a long hold-time of the cryogens, lowering the residual gas pressure and loading the trap using a technique compatible with the cryogenic environment. A novel loading technique we demonstrate successfully is laser ablation loading at 4K, employing a SrC12 target. Laser cooling is applied to produce observations of ions, both in clouds transitioning into Wigner crystals, and of linear chains of up to 14 optically resolved single ions. These results set the stage for future experiments with a planar trap for strontium-88 ions designed to operate at cryogenic temperatures.by Waseem Bakr.S.B
