We demonstrate a light-pulse atom interferometer based on the diffraction of free-falling atoms by a picosecond frequency-comb laser. More specifically, we coherently split and recombine wave packets of cold ${}^{87}\mathrm{Rb}$ atoms by driving stimulated Raman transitions between the $|5s{}^2{S}_{1/2},F=1⟩$ and $|5s{}^2{S}_{1/2},F=2⟩$ hyperfine states, using two trains of picosecond pulses in a counterpropagating geometry. We study the impact of the pulses’ length as well as the interrogation time onto the contrast of the atom interferometer. Our experimental data are well reproduced by a numerical simulation based on an effective coupling that depends on the overlap between the pulses and the atomic cloud. These results pave the way for extending light-pulse interferometry to transitions in other spectral regions and therefore to other species, for new possibilities in metrology, sensing of gravito-inertial effects, and tests of fundamental physics.

• Received 8 July 2022
• Accepted 26 September 2022

DOI:https://doi.org/10.1103/PhysRevLett.129.173204