The Key Technology Of Miniaturization Of Strontium Clock And The Realization Of Primary Cooling

Time is closely related to human production and life.The accuracy of time measurement methods has greatly affected the development of various industries.In recent years,more and more researches have been carried out around the time measurement tool,the neutral atomic clock.At the same time,the uncertainty and stability of the neutral atomic optical clock have been greatly improved.It is currently the most accurate timing tool.Optical clock systems using strontium metal as a neutral atom have excellent performance in various types of atomic clocks at present,and are most likely to become a new-generation time-frequency reference measurement tool.At present,the Frequency uncertainty of strontium optical clock in the laboratory can reach 10^-19.But the strontium optical clock system now in the laboratory is large and complicated,and the mobility is poor,which greatly limits its application in industry and other scientific research fields.Based on the space strontium atomic light clock plan.,this thesis focuses on the miniaturization of the space strontium light clock physical system and the integrated design of the primary cooling light path.The work completed is as follows:（1）This thesis firstly optimizes the optical atomic clock physical system,and discusses the improvements in volume,power consumption,and structural stability of each component,including the design of a low-power and internal heating strontium atomic furnace,and integrated frequency locking on the physical system.In addition,a miniaturized magneto-optical trap cavity is also designed.（2）The research of the Zeeman slower with small volume,low energy consumption and high deceleration efficiency.First,a ring-shaped permanent magnet was made based on the magnetic field of 12 groups of energized coils,but the residual magnetic field of the permanent magnet at the center of the MOT cavity was measured.There is still 27 Gauss,which seriously affects the primary cooling and capture of strontium atoms.Aiming at this problem,we have developed a small coil slower with a length of10cm,and further proposed a symmetrical magnetic field theory to reduce the coil heating.（3）Integrated processing of the first-stage cooling light path.Considering the complex internal components of the frequency-doubled laser and the poor seismic performance,this article uses a simpler external cavity semiconductor laser,while using injection locking technology to solve the problem of 461nm laser power shortage.After adding the injection-locked optical path,the primary optical path was redesigned,and the entire optical path was integrated on a double-layer panel of 0.56m×0.44m.At the same time,part of the spatial optical path was replaced with an optical fiber path,which enhanced the system’s modularity and seismic performance.（4）After improving each part of the physical system,the assembled physical system and integrated optical panel are used to experimentally complete the first-stage cooling and capture of the strontium atom.According to the Doppler velocimetry method,under the action of Zeeman sower and 461nm decelerating light,the most probable velocity of the strontium atomic group is reduced from 460m/s to 75m/s.The number of captured atoms measured by fluorescence collection method is 2×10⁶.After adding 679nm and707nm repumping light,the number of captured atoms increases to 1.34×10⁷.The temperature of the trapped atomic cluster was measured by the short-range time-of-flight method,and the result was 11 mk.