A clock transition for a future optical frequency standard with trapped atoms

I. Courtillot, A. Quessada, R. P. Kovacich +5

We report the first direct excitation of the strongly forbidden 5s2 1S0-5s5p 3P0 transition in 87Sr. Its frequency is 429 228 004 235 (20) kHz. A resonant laser creates a small lea…