1,721,039 research outputs found
Reduction of the cold collisions frequency shift in a multiple velocity fountain: a new proposal
No full textIn this paper, we propose a new scheme for operating an atomic fountain frequency standard. A sequence of time-spaced balls of atoms, launched over nonoverlapping trajectories, makes possible a reduction of the atomic density and consequently the cold collision frequency shift by one order of magnitude without significant reduction of the useful signal and of the overall stability of the clock. The ultimate accuracy of a Cs fountain could be improved below the 10-15 level currently achieved in operating clock
Coherent microwave emission without population inversion: A new atomic frequency standard
No full textThe light shift effect in the coherent population trapping cesium maser
No full textSummary: The light shift, as observed in the coherent population trapping (CPT) maser, was investigated theoretically and experimentally. It was found that the light shift originates from the various sidebands that are present in the spectrum of the frequency....
ac Stark shift measurements of the clock transition in cold Cs atoms: Scalar and tensor light shifts of the D2 transition
Full text linkThe ac Stark shift, or light shift, is a physical phenomenon that plays a fundamental role in many applications ranging from basic atomic physics to applied quantum electronics. Here, we discuss experiments testing light-shift theory in a cold-atom cesium fountain clock for the Cs D2 transition (i.e., 6 2S1/2 → 6 2P3/2 at 852 nm). Cold-atom fountains represent a nearly ideal system for the study of light shifts: (1) The atoms can be perturbed by a field of arbitrary character (e.g., coherent field or nonclassical field); (2) there are no trapping fields to complicate data interpretation; (3) the probed atoms are essentially motionless in their center-of-mass reference frame, T ∼ 1 μK; and (4) the atoms are in an essentially collisionless environment. Moreover, in the present work the resolution of the Cs excited-state hyperfine splittings implies that the D2 ac Stark shift contains a nonzero tensor polarizability contribution, which does not appear in vapor phase experiments due to Doppler broadening. Here, we test the linearity of the ac Stark shift with field intensity, and measure the light shift as a function of field frequency, generating a "light-shift curve." We have improved on the previous best test of theory by a factor of 2, and after subtracting the theoretical scalar light shift from the experimental light-shift curves, we have isolated and tested the tensor light shift for an alkali D2 transition
Improving short and long term stability of pulsed optically pumped vapor cell frequency standards
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