Detection Of Clock Transition In Magnesium-Aluminum Ion Optical Clock Based On Quantum Logic Technique

With the development of science and technology,people's understanding of time has deepened.The special theory of relativity has introduced the concept of time to a new dimension,and at the same time,the accuracy of time is getting better and better.From sidereal day to the quartz crystal oscillator,then to the cesium atomic clock,the relative uncertainty of the second has reached 10-16,which is sufficient to observe the relativistic effect and is widely used in fundamental physics and modern industry.In addition,the precision of time measurement is the highest of all physical units.Thanks to the conversion of time and frequency t=1/f,scientists can convert high-precision measurement of frequency into high-precision measurement of time.Calibration of current,voltage,and length can also be derived from frequency to improve the accuracy of other basic units.On the other hand,scientists have not been satisfied with the relative uncertainty of the frequency standard of 10-16,and have successfully realized the atomic and ionic optical clocks of various elements.Currently,optical clocks with the uncertainty level of 10-19 has been achieved,which is promising for the definition of the next generation of seconds.In this context,based on the natural superiority of aluminum ion optical clock to black body radiation,the key technology research of aluminum ion optical frequency standard system based on quantum logic technique is carried out.The corresponding key technologies were realized,including vacuum system(10-8 Pa),fluorescence collection system and optical path system,and the magnesium atoms were successfully ionized by two-photon ionization trapped in ion trap.My doctoral subject is based on these experimental bases,the detection of clock transition in magnesium-aluminum ion optical clock,mainly includes the following three aspects:1,Designed a new scheme of ion trap.Which was to ensure an overall fluorescence collection rate of 0.2%while the heating rate was 2.3(4)phonon/s.2,Proposed efficient Raman sideband cooling strategy.By using Raman sideband cooling technique,a combination of second-order and first-order sideband cooling was applied.The magnesium ion was cooled from the Doppler limit temperature of 1 mK and the average vibration quantum number n=17(3)to n=0.01(1)at 77 ?K in 3 millisenconds.3,Cconstructed a simulation system based on rate equation and simulates some experiments such as the preparation process of aluminum ion state.The magnesium-aluminum ions were Raman sideband cooled to the vibration ground state,the average vibration quantum number of the center of mass mode was n=0.01(1),the breathing mode n=0.1(1).Based on the Raman sideband technique,under the joint efforts of the research team,we successfully detected |1S0,F=5/2>?|3P1,F=7/2>quantum logic transition signal.Based on the quantum logic technique,the clock transition detection scheme was proposed and the |1S0>?|3P0>clock transition signal was successfully detected experimentally with team members.The FWHD of transition was 0.8(1)kHz.The work of my doctoral period laid a solid foundation for the realization of closed-loop locking and error evaluation of magnesium-aluminum ion optical frequency standard system in the future.