NEARLY ALL-OPTICAL FREQUENCY-STABILIZATION OF A LASER-DIODE ON THE 120 KHZ INTERCOMBINATION LINE OF BA

A standard semiconductor laser at 791 nm is optically stabilized onto the narrow intercombination line of Ba (natural width: 120 kHz) in a n early all-optical scheme relying on the optical feedback induced in co llinear polarization spectroscopy. Fast frequency fluctuations of the laser are reduced in spite of the finite response time of the atomic s ignal. By monitoring the frequency beat between two independently stab ilized lasers, we observe that the laser jitter is smaller than 100 kH z, the relative square-root of Allan Variance is below 10(-11) in the 0.1-1s range, and the reproducibility in the 500 kHz range.