Abstract

We report on progress of generating ultracold atoms of magnesium. Magnesium belongs to the few elements suited for a neutral atom optical frequency standard. Its unique properties such as a very low black body radiation shift, the occurrence of fermionic and bosonic isotopes of suitable abundance, and the existence of a magic wavelength make it a very attractive candidate for future optical clocks. With our experiment, we determined for the first time the absolute frequency of the intercombination transition 3¹S⁰? 3³P¹of²⁴Mg with a Ramsey-Bord Enterferometer, which was linked to a primary Cs Frequency standard of the PTB via a fiber femtosecond laser. Cooling ensembles of magnesium in the non-magnetic ground state to microkelvins is difficult as standard sub-Doppler cooling schemes are not applicable. We investigate novel methods to lower the temperatures of magnesium atoms. One promising method is based on a coherent two photon-process which provides higher velocity selectivity. Alternatively, standard sub-Doppler cooling schemes are applicable to the long-lived excited state, which in addition can be confined in magnetic traps. Article not available.

© 2007 Optical Society of America