Study On Cooling Of The Ions And The Temperature-driven Structural Phase Transition Of The Ion Crystals In Surface Ion Trap

The ion trap system is one of the ideal platforms to explore non-classical phenomena in the microscopic world and build quantum computers,because of its long coherence time and highly efficient detection.In a surface ion trap,all the electrodes are placed in a plane so that the trapped ions can be controlled to move freely in parallel to the trap surface,which makes the surface ion traps scale up more easily than the linear ion traps.My research work during doctoral period with surface ion trap is summarized in this dissertation,including the installation and optimization of the trap system,the ions’trapping,cooling and micromotion compensation,and the structural phase transition of the ion crystals.The main content are:1、Numerical simulation of the trapping potential and the stable zone of the surface ion trap.2、Building the experiment system of the surface ion trap with following optimizations:the geomagnetic field is compensated by magnetic field coils,the frequency of the lasers are locked by optical resonator cavities,and the experimental control system is setup by FPGA and computers.3、Compensating the micromotion of the trapped ions three-dimensionally.The existing method of compensating the ion’s micromotion is modified and eventually the temperature of the ion is cooled near the limit of Doppler cooling.4、Experimental demonstration of a temperature-driven structural phase transition of the ion crystals.The temperature-driven structural phase transition is measured.The phase diagram and the relation of the transition point varies with the potential of trap are drawn.It is shown that thermal fluctuations can also be exploited as a beneficial condition in microscopic level systems.5、Exploration of the sub-Doppler cooling for the ions.