Blue fluorescence as a frequency offset reference in the rubidium 5S-5P-5D transition.

In this work, we address the issue of the suitability of blue fluorescent light as a frequency offset reference during the ladder-level excitation 5S→5P→5D of Rb85 atoms. A simple pump-probe spectroscopy experiment is performed to generate non-degenerate blue light emission produced by the spontaneous decay route 5D→6P→5S. By varying the relative intensity of the pump-probe combination, we can hover between regimes dominated by mechanisms such as double resonance optical pumping (DROP) and Autler-Townes splitting.