Frequency-Stability Performances of the Pulsed Optically Pumped Rubidium Clock: Recent Results and Future Perspectives

This paper presents new results obtained with a laboratory prototype of a pulsed optically pumped frequency standard based on a vapor cell containing $^{87}\hbox{Rb}$ diluted in a buffer gas. A frequency stability of about $1.2 \times 10^{-12}$ $\tau^{-1/2}$ has been measured, and the value of $3 \times 10^{-15}$ for integration times of $10^{5}$ s has been achieved (drift removed data). These performances show that a suitable implementation of this standard can lead to a compact vapor-cell clock with a very interesting short- and medium-term frequency stability and, consequently, may be of great interest in radio-navigation systems. We also present some possible improvements of the pulsed technique.