Non-destructive measurement of the transition probability in a Sr optical lattice clock

TL;DR

This paper demonstrates a non-destructive optical measurement technique for the Sr optical lattice clock, enabling repeated measurements on the same atoms and improving clock stability.

Contribution

It introduces a phase-shift based differential measurement method for non-destructive probing of the clock transition in Sr atoms, enhancing clock operation efficiency.

Findings

Achieved detection of 10^4 atoms with SNR of 100 per cycle

Maintained over 95% atom retention in the optical lattice

Enabled repeated measurements to improve clock stability

Abstract

We present the experimental demonstration of non-destructive probing of the 1S0-3P0 clock transition probability in an optical lattice clock with 87Sr atoms. It is based on the phase shift induced by the atoms on a weak off-resonant laser beam. The method we propose is a differential measurement of this phase shift on two modulation sidebands with opposite detuning with respect to the 1S0-1P1 transition, allowing a detection limited by the photon shot noise. We have measured an atomic population of 10^4 atoms with a signal to noise ratio of 100 per cycle, while keeping more than 95% of the atoms in the optical lattice with a depth of 0.1 mK. The method proves simple and robust enough to be operated as part of the whole clock setup. This detection scheme enables us to reuse atoms for subsequent clock state interrogations, dramatically reducing the loading time and thereby improving the clock frequency stability.