{"paper":{"title":"Measurements of the instantaneous velocity difference and local velocity with a fiber-optic coupler","license":"","headline":"","cross_cats":["astro-ph","cond-mat.soft","physics.ins-det","physics.optics"],"primary_cat":"physics.flu-dyn","authors_text":"(2) Department of Physics, (3) Department of Biological Physics, Astronomy, B. J. Ackerson (1), Eotvos University, Hungary), Oklahoma State University, P. Tong (1), S. H. Yao (1), University of Pittsburgh, V. K. Horv\\'ath (2) (3), W. I. Goldburg (2) ((1) Department of Physics","submitted_at":"2000-10-06T23:06:43Z","abstract_excerpt":"New optical arrangements with two single-mode input fibers and a fiber-optic coupler are devised to measure the instantaneous velocity difference and local velocity. The fibers and the coupler are polarization-preserving to guarantee a high signal-to-noise ratio. When the two input fibers are used to collect the scattered light with the same momentum transfer vector but from two spatially separated regions in a flow, the obtained signals interfere when combined via the fiber-optic coupler. The resultant light received by a photomultiplier tube contains a cross-beat frequency proportional to th"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"physics/0010021","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"}