Recently, based on the collaboration of the ion trap group and atomic and molecular external field theory group of WIPM, new progress in precision spectroscopy of trapped and cold 40Ca+ is achieved, the results are published in Phys. Rev. Lett. (PRL 114, 223001 (2015)).
In a special laser field, the two energy levels of a special optical transition of an atom have same dipole polarizability, thus, the frequency shift is zero, and so, the wavelengths of the laser are called magic wavelengths. Magic wavelengths make the manipulation of independent control of internal hyperfine-spin and external center-of-mass motions of atoms come true, and it will have broad application in the research of quantum state manipulation and precision spectroscopy. Especially, the development of the neutral atomic optical lattice clocks based on magic wavelengths is one of the trends of the atomic clocks. Whether the magic wavelengths exist in ion system, And whether magic wavelengths can be measured with high precision in ion system and have new and possible application?
Previously, the researchers of atomic and molecular external field theory group of WIPM calculated and achieved the theoretical values of magic wavelengths of 4S1/2-3D5/2 in 40Ca+ (Phys. Rev. A 87, 042517 (2013)). Recently, based on the established single trapped and cold 40Ca+ optical clocks, the ion trap group measured precisely the optical shift of 40Ca+ optical transition in special laser wavelengths, and the experimental values of magic wavelengths are achieved, with the precision of 2 ppm, and the experimental and theoretic values are coincidental. Based on the experimental values of magic wavelengths, the oscillator strength ratio of 4S1/2-4P1/2 and 4S1/2-4P3/2 is achieved, which provides the experimental evidence for studying atomic fine structure. The results provide new idea for improving the accuracy of precision spectroscopy, and are also the basis for all-optical trapped ion clocks in future. At the same time, based on the collaboration of theory and experiment, the researchers of ion trap group measured precisely the lifetime of 3D5/2 in 40Ca+.
The research is supported by the National Basic Research Program of China , the National Natural Science Foundation of China and the Chinese Academy of Sciences.
Website of this PRL paper: http://journals.aps.org/prl/pdf/10.1103/PhysRevLett.114.223001
