Cold SR atoms for an optical frequency standard

Quessada, Courtillot, Kovacich +6 more

N. Poli

Paul-Éric Pottie, T. Binnewies, Hardo Stoehr +3 more

Sr-atoms are of special interest for an optical frequency standard since a large number of atoms can be cooled down efficiently to ultra-low temperatures in a magneto-optical trap (MOT). The ultra-narrow line on the forbidden 1 S 0 -> 3 P 0 transition of 87 Sr ( 3 P 0 natural lifetime is approx. 100 s), and the ability to interrogate Sr atoms in a perturbation free dipole trap promise un-precedented low inaccuracy level and relative frequency instability, well below 10 -15 tau -1/2 . We will show the realization of an efficient atomic source of cold Sr atoms and the construction of an ultra-stable laser for the interrogation of the atoms.

Reinaldo L. Cavasso-Filho, Daniela A. Manoel, D. Ortega +3 more

Irène Ventrillard, Audrey Quessada, Richard P. Kovacich +5 more

We report the capture of cold strontium atoms in a magnetooptical trap at a rate of 3/spl times/10/sup 10/ atoms/s. This is achieved with high power laser light at 461 nm generated by sum frequency mixing in a potassium titanyl phosphate (KTP) crystal using diode lasers at 813 nm and a Nd:YAG laser at 1064 nm. Up to 115 mW of blue light is obtained. Tuned to the /sup 1/S/sub 0//spl rarr//sup 1/P/sub 1/ of /sup 88/Sr, this light is used both to slow down an atomic beam in a Zeeman slower and to capture the atoms in a magnetooptical trap. Trapping of /sup 87/Sr and /sup 86/Sr is also reported.

Vladilen S Letokhov, Vladimir G. Minogin

The results of studies into the laser cooling of atoms have been summarized and the possibilities of application of cold atoms in frequency standards have been considered. It has been shown that the optical frequency standard on the basis of laser-cooled atoms Mg, Ca or Sr may have the long-term stability of about 10-15.