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Progress towards optical frequency standards based on two-photon transitions in atomic silver

We report advances towards the development of frequency standards based on narrow two-photon transitions in the silver atom at 576 and 661 nm from the ground 4d105s2S1/2 state to the 2D3/2,5/2 levels of the configuration 4d95s2. We describe detection schemes for metastable atoms, localisation of the position of the metastable 2D5/2 level and diode-pumped Nd:YLF lasers around 1.3 μm destined to replace dye lasers for both cooling and spectroscopy of the clock transition. Our result for the position of the 2D5/2 level is more than a factor of two improvement over previous vales.