{"id":6128,"date":"2026-05-29T15:34:27","date_gmt":"2026-05-29T13:34:27","guid":{"rendered":"https:\/\/www.swissrocketman.fr\/Wordpress\/?p=6128"},"modified":"2026-05-31T18:51:59","modified_gmt":"2026-05-31T16:51:59","slug":"leffet-hanbury-brown-twiss-hbt-est-un-phenomene-de-correlation-statistique-entre-photons","status":"publish","type":"post","link":"https:\/\/www.swissrocketman.fr\/Wordpress\/leffet-hanbury-brown-twiss-hbt-est-un-phenomene-de-correlation-statistique-entre-photons\/","title":{"rendered":"L’effet Hanbury Brown\u2013Twiss (HBT) est un ph\u00e9nom\u00e8ne de corr\u00e9lation statistique entre photons"},"content":{"rendered":"

L’effet Hanbury Brown\u2013Twiss (HBT)<\/strong> est un ph\u00e9nom\u00e8ne de corr\u00e9lation statistique entre photons, d\u00e9couvert dans les ann\u00e9es 1950 par Robert Hanbury Brown<\/span><\/span> et Richard Q. Twiss<\/span><\/span>.<\/p>\n

Principe<\/h3>\n

Au lieu de mesurer directement les interf\u00e9rences d’un faisceau lumineux (comme dans un interf\u00e9rom\u00e8tre classique), on mesure les corr\u00e9lations temporelles<\/strong> entre les photons d\u00e9tect\u00e9s par deux d\u00e9tecteurs.<\/p>\n

L’exp\u00e9rience typique consiste \u00e0 :<\/p>\n

    \n
  1. Diviser un faisceau lumineux avec une lame s\u00e9paratrice.<\/li>\n
  2. Envoyer chaque moiti\u00e9 vers un photod\u00e9tecteur.<\/li>\n
  3. Mesurer la probabilit\u00e9 que les deux d\u00e9tecteurs enregistrent un photon simultan\u00e9ment.<\/li>\n<\/ol>\n

    On d\u00e9finit alors la fonction de corr\u00e9lation d’ordre 2 :<\/p>\n

    g(2)(\u03c4)g^{(2)}(\\tau)<\/span>g<\/span>(<\/span>2)<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>\u03c4<\/span>)<\/span><\/span><\/span><\/span><\/span><\/p>\n

    o\u00f9 \u03c4\\tau<\/span>\u03c4<\/span><\/span><\/span><\/span> est le retard temporel entre les deux d\u00e9tections.<\/p>\n

    Ce que mesure le HBT<\/h3>\n

    Lumi\u00e8re thermique (lampe, \u00e9toile, plasma)<\/h4>\n

    Les photons ont tendance \u00e0 arriver en \u00ab paquets \u00bb (bunching) :<\/p>\n

    g(2)(0)=2g^{(2)}(0)=2<\/span>g<\/span>(<\/span>2)<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>0<\/span>)<\/span>=<\/span><\/span>2<\/span><\/span><\/span><\/span><\/span><\/p>\n

    On observe plus de co\u00efncidences que pr\u00e9vu au hasard.<\/p>\n

    Laser id\u00e9al<\/h4>\n

    Les photons arrivent de fa\u00e7on al\u00e9atoire :<\/p>\n

    g(2)(0)=1g^{(2)}(0)=1<\/span>g<\/span>(<\/span>2)<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>0<\/span>)<\/span>=<\/span><\/span>1<\/span><\/span><\/span><\/span><\/span><\/p>\n

    Pas de regroupement particulier.<\/p>\n

    Source \u00e0 photon unique<\/h4>\n

    Les photons ne peuvent pas arriver simultan\u00e9ment :<\/p>\n

    g(2)(0)=0g^{(2)}(0)=0<\/span>g<\/span>(<\/span>2)<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>0<\/span>)<\/span>=<\/span><\/span>0<\/span><\/span><\/span><\/span><\/span><\/p>\n

    C’est l’antibunching<\/strong>, signature fondamentale d’une v\u00e9ritable source de photons uniques.<\/p>\n

    Lien avec votre photomultiplicateur H7155<\/h3>\n

    Comme vous m’interrogiez pr\u00e9c\u00e9demment sur le module PMT H7155, deux H7155 peuvent \u00eatre utilis\u00e9s dans un montage HBT :<\/p>\n

    \n
    \n
    \n
    \n
    \n
    \n
    \n
    <\/div>\n
    \n
    \n
    \n
    \n
    \n
    Source lumineuse\r\n       |\r\n   S\u00e9parateur 50\/50\r\n      \/    \\\r\n   PMT1    PMT2\r\n      \\    \/\r\n   Compteur de co\u00efncidences<\/code><\/pre>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n
    \n
    <\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n
    Ce montage permet de d\u00e9terminer si la source \u00e9met :<\/p>\n
      \n
    • une lumi\u00e8re thermique,<\/li>\n
    • une lumi\u00e8re laser,<\/li>\n
    • ou des photons uniques.<\/li>\n<\/ul>\n
      Application historique<\/h3>\n
      L’exp\u00e9rience originale de Hanbury Brown et Twiss a servi \u00e0 mesurer le diam\u00e8tre apparent des \u00e9toiles gr\u00e2ce \u00e0 l’\u00ab interf\u00e9rom\u00e9trie d’intensit\u00e9 \u00bb. Cette technique a notamment \u00e9t\u00e9 utilis\u00e9e \u00e0 l’Narrabri Stellar Intensity Interferometer<\/span><\/span>.<\/p>\n
      Pourquoi c’est important aujourd’hui ?<\/h3>\n
      L’effet HBT est devenu un outil fondamental en :<\/p>\n
        \n
      • optique quantique,<\/li>\n
      • information quantique,<\/li>\n
      • cryptographie quantique,<\/li>\n
      • caract\u00e9risation des sources \u00e0 photons uniques,<\/li>\n
      • physique des atomes et des ions pi\u00e9g\u00e9s.<\/li>\n
      • \n
        Dans votre contexte de comptage de photons avec le H7155, la mesure de g(2)(0)g^{(2)}(0)<\/span>g<\/span>(<\/span>2)<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>(<\/span>0<\/span>)<\/span><\/span><\/span><\/span> est pr\u00e9cis\u00e9ment la m\u00e9thode utilis\u00e9e pour d\u00e9montrer qu’une source \u00e9met r\u00e9ellement des photons un par un et non de faibles impulsions lumineuses contenant plusieurs photons.<\/span><\/h3>\n<\/li>\n<\/ul>\n<\/div><\/section><\/div>\n
        <\/div><\/div><\/div><\/div>\n
        EXPERIENCE EN COURS<\/strong><\/span><\/h1>\n<\/div><\/section><\/div>
        <\/div><\/p>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":6133,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11],"tags":[],"class_list":["post-6128","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-experiences-lasers"],"_links":{"self":[{"href":"https:\/\/www.swissrocketman.fr\/Wordpress\/wp-json\/wp\/v2\/posts\/6128","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.swissrocketman.fr\/Wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.swissrocketman.fr\/Wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.swissrocketman.fr\/Wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.swissrocketman.fr\/Wordpress\/wp-json\/wp\/v2\/comments?post=6128"}],"version-history":[{"count":5,"href":"https:\/\/www.swissrocketman.fr\/Wordpress\/wp-json\/wp\/v2\/posts\/6128\/revisions"}],"predecessor-version":[{"id":6177,"href":"https:\/\/www.swissrocketman.fr\/Wordpress\/wp-json\/wp\/v2\/posts\/6128\/revisions\/6177"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.swissrocketman.fr\/Wordpress\/wp-json\/wp\/v2\/media\/6133"}],"wp:attachment":[{"href":"https:\/\/www.swissrocketman.fr\/Wordpress\/wp-json\/wp\/v2\/media?parent=6128"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.swissrocketman.fr\/Wordpress\/wp-json\/wp\/v2\/categories?post=6128"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.swissrocketman.fr\/Wordpress\/wp-json\/wp\/v2\/tags?post=6128"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}