Project supported by the National Key Research and Development Program of China(Grant Nos.2017YFA0304401,2018YFA0307500,2017YFA0304404,and 2017YFF0212003);the National Natural Science Foundation of China(Grant Nos.11622434,11774388,11634013,11934014,and 91736310);the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB21030100);the CAS Youth Innovation Promotion Association(Grant Nos.Y201963 and 2018364);the Science Fund for Distinguished Young Scholars of Hubei Province,China(Grant No.2017CFA040).
Progress of the ^40Ca^+ion optical clock based on the 4^2S1/2-3d ^2D5/2 electric quadrupole transition is reported.By setting the drive frequency to the“magic”frequencyΩ0,the frequency uncertainty caused by the scal...