STAGE OFFRE DE STAGE: HIGH STABILITY OPTICAL LATTICE CLOCKS

SYRTE is developing optical lattice clocks with strontium atoms. These clocks, in which an ensemble of 104 ultra-cold atoms tightly confined in an optical lattice are probed by an ultra-stable laser, are the most stable and accurate frequency standards. They have applications in fundamental physics (test of relativity, search for dark matter,…), in geodesy, in precise timing for astronomy or industry. Within the next 10 years, a redefinition of the SI second taking advantage of the high performances of optical clocks is expected.



Two strontium optical lattice clocks are now operational at SYRTE. They have contributed to the fine characterization of systematic effects, international clocks comparisons [3], tests of Lorentz invariance [2], the calibration of TAI (Temps Atomique International) [3].They have been used to demonstrate a non-destructive readout of the transition probability, using the dispersive properties of strontium, probed by a high finesse cavity surrounding the atoms [1]. This detection shows a very high signal-to-noise ratio (it can detection a few atoms in the lattice), while only seldom perturbing the atomic state. The aim of this internship proposed here is to exploit this detection in order to demonstrate an improved clock stability. For this, the detection will be used to recycle the detected atoms, thus ensuring a faster repetition rate of the clock sequence, and hence a better statistical resolution.