Observation of atomic speckle and Hanbury Brown–Twiss correlations in guided matter waves

• Published in: Nature communications 2011, Vol.2 (1), p.291-291, Article 291
• Main Authors: Dall, R.G., Hodgman, S.S., Manning, A.G., Johnsson, M.T., Baldwin, K.G.H., Truscott, A.G.
• Format: Article
• Language: English
• Subjects: 639/766/119; 639/766/36; 639/766/400/482; Helium - chemistry; Humanities and Social Sciences; Interferometry - methods; Lasers; Light; Models, Chemical; multidisciplinary; Optics and Photonics; Photons; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms1292

Speckle patterns produced by multiple independent light sources are a manifestation of the coherence of the light field. Second-order correlations exhibited in phenomena such as photon bunching, termed the Hanbury Brown–Twiss effect, are a measure of quantum coherence. Here we observe for the first time atomic speckle produced by atoms transmitted through an optical waveguide, and link this to second-order correlations of the atomic arrival times. We show that multimode matter-wave guiding, which is directly analogous to multimode light guiding in optical fibres, produces a speckled transverse intensity pattern and atom bunching, whereas single-mode guiding of atoms that are output-coupled from a Bose–Einstein condensate yields a smooth intensity profile and a second-order correlation value of unity. Both first- and second-order coherence are important for applications requiring a fully coherent atomic source, such as squeezed-atom interferometry. Speckle patterns are a manifestation of decoherence and can result from two-particle interference. Here, the authors image atomic speckle for guided matter waves and link this to atom bunching in the second-order correlation function, suggesting potential use in squeezed-atom interferometry applications.