Research On Key Technologies In Quantum Logic Based Magnesium-Aluminm Ion Optical Clock

Time and frequency is the most accurate physical quantities that can be measured nowadays.For Cesium fountain clocks,the systematic uncertainty has been evaluated down to 10^-16 level.For the new generation clocks based on optical transitions,i.e.optical clocks,the systematic uncertainty can be as low as 10^-18 or even 10^-19 level.Precision frequency standards are playing key roles in areas like metrology,satellite navigation,deep space exploration,very long baseline interferometry,and fundamental physical laws test.The natural linewidth of ²⁷Al⁺ion optical clock transition ¹S₀–³P₀ is about 8 mHz.Due to its multiple advantages,such as no electrical quadrupole shift,insensitivity to magnetic field,and low sensitivity to blackbody radiation,²⁷Al⁺ion optical clocks have been actively investigated in recent years.However,the ²⁷Al⁺direct cooling transition ¹S₀–¹P₁ is at 167nm,which is difficult to obtain at the moment.It means that ²⁷Al⁺ions cannot be directly Doppler cooled and detected.To solve this problem,quantum logic based clock scheme is used.In our setup,we use a co-trapped ²⁵Mg⁺ion to sympathetically cool ²⁷Al⁺ion and detect the internal state of ²⁷Al⁺ion through quantum logic technique.This thesis will talk about experimental works on ²⁵Mg⁺ion laser cooling and ²⁵Mg⁺-²⁷Al⁺sympathetic cooling.The main research works include the following:1.Built up the physical system of ²⁷Al⁺ion clock and its control software;2.Use Raman sideband cooling technique to cool ²⁵Mg⁺-²⁷Al⁺ion pair to their motion ground state and measure ²⁵Mg⁺ion ground state hyperfine constant.3.Detect the ²⁷Al⁺¹S₀–³P₁ transition spectrum by using quantum logic technique.The aforementioned studies establish good working base for the success of the ²⁷Al⁺ion optical clock project.