Detection of the phase shift which accompanies the excitation of an atomic beam by N. F. Ramsey's method

Uwe Sterr, K. Sengstock, G. Hennig +3 more

Based on a new detection scheme, optical Ramsey fringes with a resolution of 4 kHz on the Mg 1S0‐3P1 intercombination line (λ=457 nm) have been detected using laser cooled and trapped atoms. Due to a pulsed excitation sequence, the signals are free from phase errors caused by the interacting laser fields and by the relativistic Doppler effect, resulting in an accuracy better than Δν/ν≊10−15. The influence of the electron shelving in the metastable 3P1 level on the trap dynamics is monitored on the fast and closed 1S0‐1P1 cooling transition (λ=285 nm). Simultaneously recorded Ramsey fringes on a thermal atomic beam allow a direct measurement of the second order Doppler shift.

J. J. Snyder, J. Helmcke, M. Gläser +1 more

V. A. Grinchuk, E. F. Kuzin, M. L. Nagaeva +4 more

M. Brune, S. Haroche, V. Lefèvre-Seguin +2 more

We describe a new quantum nondemolition method to monitor the number N of photons in a microwave cavity. We propose coupling the field to a quasiresonant beam of Rydberg atoms and measuring the resulting phase shift of the atom wave function by the Ramsey separated-oscillatory-fields technique. The detection of a sequence of atoms reduces the field into a Fock state. With realistic Rydberg atom-cavity systems, small-photon-number states down to N=0 could be prepared and continuously monitored.

Hikaru Tamura, Huy Minh Nguyen, P. R. Berman +1 more

J. Helmcke, M. Gläser, F. Riehle +2 more

A procedure is suggested for compensating the broadening due to the quadratic Doppler effect and for band shifts caused by phase mismatch in the observation of a Ramsey signal in an atomic calcium beam. The relative error in the frequency stabilized by this method is estimated to be 2 × 10 − 12 .