{"paper":{"title":"XUV frequency comb metrology on the ground state of helium","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["physics.optics"],"primary_cat":"physics.atom-ph","authors_text":"Christoph Gohle, Dominik Z. Kandula, Kjeld S.E. Eikema, Tjeerd J. Pinkert, Wim Ubachs","submitted_at":"2011-09-15T00:00:12Z","abstract_excerpt":"The operation of a frequency comb at extreme ultraviolet (XUV) wavelengths based on pair-wise amplification and nonlinear upconversion to the 15th harmonic of pulses from a frequency comb laser in the near-infrared range is reported. Following a first account of the experiment [Kandula et al., Phys. Rev. Lett. 105, 063001 (2010)], an extensive review is given of the demonstration that the resulting spectrum at 51 nm is fully phase coherent and can be applied to precision metrology. The pulses are used in a scheme of direct-frequency-comb excitation of helium atoms from the ground state to the "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1109.3228","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}