Lattice-induced photon scattering in an optical lattice clock

authored by
Sören Dörscher, Roman Schwarz, Ali Al-Masoudi, Stephan Falke, Uwe Sterr, Christian Lisdat

We investigate scattering of lattice laser radiation in a strontium optical lattice clock and its implications for operating clocks at interrogation times up to several tens of seconds. Rayleigh scattering does not cause significant decoherence of the atomic superposition state near a magic wavelength. Among the Raman scattering processes, lattice-induced decay of the excited state (5s5p)P03 to the ground state (5s2)S01 via the state (5s5p)P13 is particularly relevant, as it reduces the effective lifetime of the excited state and gives rise to quantum projection noise in spectroscopy. We observe this process in our experiment and find a decay rate of 556(15)×10-6s-1 per photon recoil energy Er of effective lattice depth, which agrees well with the rate we predict from atomic data. We also derive a natural lifetime τ=330(140)s of the excited state P03 from our observations. Lattice-induced decay thus exceeds spontaneous decay at typical lattice depths used by present clocks. It eventually limits interrogation times in clocks restricted to high-intensity lattices but can be largely avoided, e.g., by operating them with shallow lattice potentials.

External Organisation(s)
National Metrology Institute of Germany (PTB)
Toptica Photonics
Physical Review A
Publication date
Publication status
Peer reviewed
ASJC Scopus subject areas
Atomic and Molecular Physics, and Optics
Electronic version(s) (Access: Unknown)