Zhong Jiaqi

Magic Wavelength of an Optical Clock Transition of Barium

Similar to most of the other alkaline earth elements, barium atoms can be candidates for optical clocks, thus the magic wavelength for an optical lattice is important for the clock transition. We calculate the magic wavelength of a possible clock transition between 6s(2) (1) S(0) and 6s5d (3) D(2) states of barium atoms. Our theoretical result shows that there are three magic wavelengths 615.9 nm, 641.2nm and 678.8nm for a linearly polarized optical lattice laser for barium.

Direct measurement of light speed reduction in a rubidium vapour medium coherently prepared by electromagnetically induced transparency

We have experimentally observed the reduction of light speed in a rubidium vapour medium coherently prepared by electromagnetically induced transparency. The light speed reduction was deduced by directly measuring the time delay of a probe light when it passed through the medium. The time delay varies with the intensity of the coupling laser, and the typical time delay we recorded was 1.8 μs, corresponding to a light speed of 56000 m/s.