Study On Microwave Transition Spectral Precision Measurements On Laser-cooled ¹⁹⁹Hg⁺²S_1/2F=1→F=0

Atomic clocks provide the basic time reference benchmark for the operation of human society.The optical clock has gradually entered the practical stage,but both the optical clock system based on single trapped ion and multiple atoms in the optical lattice are facing the problem of miniaturization.The microwave clock is more maturely developed,and the ¹⁹⁹Hg⁺microwave clock system has been tested in space operation and is a strong candidate for the next generation of deep space atomic clocks.Due to the difficulty of producing the 194nm coherent light source,the existing space ¹⁹⁹Hg⁺microwave clock uses Hg lamp and Helium buffer gas for ion cooling.The performance of the ¹⁹⁹Hg⁺microwave standard system can be further improved using the 194nm coherent light source for ion cooling.Experimental study on microwave transition at ²S_1/2F=0→F=1 of laser-cooled ¹⁹⁹Hg⁺is a necessary task to achieve laser cooling of ¹⁹⁹Hg⁺microwave clock.Based on the laboratory Hg⁺clock platform,The main job is ¹⁹⁹Hg⁺microwave spectrum detection.In this word,¹⁹⁹Hg⁺was produced by isotope selective photoionization.Then,194nm laser,40.5GHz microwave,and external magnetic field is used to achieve the cooling and trapping of ¹⁹⁹Hg⁺.And ¹⁹⁹Hg⁺microwave spectrum is realized by time sequence control.This work contributes to the engineering of ¹⁹⁹Hg⁺microwave clocks and the further improvement of Hg⁺optical clock performance in laboratories.In addition,experimental research,data analysis and proposed solutions were completed for the performance degradation of ultra-stable lasers used for ¹⁹⁹Hg⁺sideband cooling during frequency doubling.These efforts contribute to the better results in the experimental study on microwave transition at ²S_1/2 F=0→F=1 of laser-cooled ¹⁹⁹Hg⁺by optimate the sideband cooling.In this paper,a calculation model for frequency uncertainty evaluation is designed.Using the relativistic multi-configuration Dirac-Hartree-Fock method,the model is suitable for the calculation of multi-ion,multi-energy level and multi-physical parameters,and has been verified by the calculation of hyperfine splitting of ²⁷Al⁺,⁹Be⁺and ²⁵Mg⁺related energy levels,Zeeman effect and isotope shift factors involved in ²⁷Al⁺optical clock operation.The model can be used for the theoretical calculation of ¹⁹⁹Hg⁺in the future,and the calculated results can be combined with the experimental results to evaluate the frequency uncertainty of the ¹⁹⁹Hg⁺spectrum.