Optical Ramsey interferences on laser cooled and trapped atoms detected by electron shelving induced trap loss

Abstract

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.