Three-cornered hat versus allan covariance

International audienc

Physics characterization and frequency stability of the pulsed rubidium maser

In this paper we report the theoretical and experimental characterization of a pulsed optically pumped vapor-cell frequency standard based on the detection of the free-induction decay microwave signal. The features that make this standard similar to a pulsed passive maser are presented. In order to predict and optimize the frequency stability, thermal and shot noise sources are analyzed, as well as the conversions of the laser and microwave fluctuations into the output frequency. The experimental results obtained with a clock prototype based on 87Rb in buffer gas are compared with the theoretical predictions, showing the practical possibility to implement a frequency standard limited in the medium term only by thermal drift. The achieved frequency stability is σy(τ)=1.2×10−12τ−1∕2 for measurement times up to τ≈105 s. It represents one of the best results reported in literature for gas cell frequency standards and is compliant with the pre..

Conférence annulée en mars 2020.

International audienc

Laser intensity noise transfer for pulsed vapor-cell clocks with optical detection

We propose a signal-theory approach to estimate the contribution from laser intensity noise to the short-term stability of compact atomic clocks based on optical detection. We remove the approximation of white intensity noise, which is usually found in literature, and propose a method for a more faithful estimate, given an arbitrary noise spectrum at the input. This is of fundamental importance, since laser intensity noise is currently one of the main limiting factors of vapor-cell clocks

New microwave power control technique by light shift detection in the DM-CPT clock

International audienc