Fig. 2: Line shape of a dynamically decoupling spectroscopy sequence.
From: Dynamical decoupling of laser phase noise in compound atomic clocks
The spectroscopy signal of clock 1 is shown as a function of laser detuning (for M = 6, ϵ = 0.08 π, Td = 40 ms, and a π-pulse duration Tπ = 1 ms). The line shape expected from theory in the absence of frequency noise (solid line) features a broad central fringe as well as a complex structure far off resonance. Measurements using our strontium lattice clock without artificial noise (circles) reproduce this line shape very well. Deviations can be attributed to limited contrast (around 90%) and fluctuations of laser intensity. The central fringe covers about 25 Hz, whereas the central fringe of Ramsey spectroscopy covers only about 2 Hz at the same interrogation time (Ti ≈ 0.25 s).
