{"id":1264,"date":"2025-07-05T17:19:35","date_gmt":"2025-07-05T15:19:35","guid":{"rendered":"https:\/\/www.artinphysics.fr\/?page_id=1264"},"modified":"2025-07-05T17:19:35","modified_gmt":"2025-07-05T15:19:35","slug":"1264-2","status":"publish","type":"page","link":"https:\/\/www.artinphysics.fr\/index.php\/1264-2\/","title":{"rendered":""},"content":{"rendered":"\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"682\" src=\"https:\/\/www.artinphysics.fr\/wp-content\/uploads\/2023\/07\/praseodumYLF_LENSE_num_016-bis-1024x682.jpg\" alt=\"\" class=\"wp-image-112\" srcset=\"https:\/\/www.artinphysics.fr\/wp-content\/uploads\/2023\/07\/praseodumYLF_LENSE_num_016-bis-1024x682.jpg 1024w, https:\/\/www.artinphysics.fr\/wp-content\/uploads\/2023\/07\/praseodumYLF_LENSE_num_016-bis-300x200.jpg 300w, https:\/\/www.artinphysics.fr\/wp-content\/uploads\/2023\/07\/praseodumYLF_LENSE_num_016-bis-768x512.jpg 768w, https:\/\/www.artinphysics.fr\/wp-content\/uploads\/2023\/07\/praseodumYLF_LENSE_num_016-bis-1536x1024.jpg 1536w, https:\/\/www.artinphysics.fr\/wp-content\/uploads\/2023\/07\/praseodumYLF_LENSE_num_016-bis-507x338.jpg 507w, https:\/\/www.artinphysics.fr\/wp-content\/uploads\/2023\/07\/praseodumYLF_LENSE_num_016-bis.jpg 1883w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">Hors cadre &#8211; Mode d&#8217;\u00e9mission <\/h3>\n\n\n\n<p>Un laser est en train d\u2019\u00eatre align\u00e9 dans une relative obscurit\u00e9. La pi\u00e8ce n\u2019a pas de fen\u00eatre. Seule la lumi\u00e8re rouge du laser semble briller dans la p\u00e9nombre. Entre deux miroirs, un cristal scintille de mille feux. Sa lumi\u00e8re se r\u00e9fl\u00e9chit sur un miroir, revient sur le cristal, est amplifi\u00e9e par celui-ci, revient sur le miroir et retourne sur le cristal et ainsi ind\u00e9finiment. A la fin, un \u00e9quilibre se trouve entre la puissance cr\u00e9\u00e9e par le laser et celle qui r\u00e9ussit \u00e0 s\u2019en \u00e9chapper mais celui-ci est fortement d\u00e9pendant de la mani\u00e8re dont les miroirs sont plac\u00e9s.<\/p>\n\n\n\n<p>\u00a0<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"683\" src=\"https:\/\/www.artinphysics.fr\/wp-content\/uploads\/2023\/07\/praseodumYLF_LENSE_num_025-1024x683.jpg\" alt=\"\" class=\"wp-image-114\" srcset=\"https:\/\/www.artinphysics.fr\/wp-content\/uploads\/2023\/07\/praseodumYLF_LENSE_num_025-1024x683.jpg 1024w, https:\/\/www.artinphysics.fr\/wp-content\/uploads\/2023\/07\/praseodumYLF_LENSE_num_025-300x200.jpg 300w, https:\/\/www.artinphysics.fr\/wp-content\/uploads\/2023\/07\/praseodumYLF_LENSE_num_025-768x512.jpg 768w, https:\/\/www.artinphysics.fr\/wp-content\/uploads\/2023\/07\/praseodumYLF_LENSE_num_025-1536x1024.jpg 1536w, https:\/\/www.artinphysics.fr\/wp-content\/uploads\/2023\/07\/praseodumYLF_LENSE_num_025-2048x1365.jpg 2048w, https:\/\/www.artinphysics.fr\/wp-content\/uploads\/2023\/07\/praseodumYLF_LENSE_num_025-507x338.jpg 507w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>Les miroirs permettent en effet de guider le champ \u00e9lectromagn\u00e9tique du laser&nbsp; et dans ces conditions, il imposent des conditions l\u00e0 o\u00f9 il se trouve qui ne permettent qu\u2019\u00e0 certaines modes de champ \u00e9lectromagn\u00e9tique d\u2019exister. Le scientifique pr\u00e9sent dans la salle ne cesse de changer tr\u00e8s l\u00e9g\u00e8rement la position de ses miroirs de telle sorte que sur le mur qui se trouvait en face, le laser prenait des formes circulaires tr\u00e8s diverses.&nbsp;<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"683\" src=\"https:\/\/www.artinphysics.fr\/wp-content\/uploads\/2023\/07\/praseodumYLF_LENSE_num_060-bis-1024x683.jpg\" alt=\"\" class=\"wp-image-113\" srcset=\"https:\/\/www.artinphysics.fr\/wp-content\/uploads\/2023\/07\/praseodumYLF_LENSE_num_060-bis-1024x683.jpg 1024w, https:\/\/www.artinphysics.fr\/wp-content\/uploads\/2023\/07\/praseodumYLF_LENSE_num_060-bis-300x200.jpg 300w, https:\/\/www.artinphysics.fr\/wp-content\/uploads\/2023\/07\/praseodumYLF_LENSE_num_060-bis-768x512.jpg 768w, https:\/\/www.artinphysics.fr\/wp-content\/uploads\/2023\/07\/praseodumYLF_LENSE_num_060-bis-1536x1024.jpg 1536w, https:\/\/www.artinphysics.fr\/wp-content\/uploads\/2023\/07\/praseodumYLF_LENSE_num_060-bis-2048x1365.jpg 2048w, https:\/\/www.artinphysics.fr\/wp-content\/uploads\/2023\/07\/praseodumYLF_LENSE_num_060-bis-507x338.jpg 507w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>Je les voyais d\u00e9filer avec amusement. Leurs cot\u00e9s elliptiques en faisait des objets abstraits \u00e9tonnant que je me suis amus\u00e9 \u00e0 photographier. Il y avait l\u00e0 quelque chose d\u2019extr\u00eamement g\u00e9om\u00e9trique, presque d\u00e9routant \u2014 tant il semblait \u00e9trange qu\u2019une lumi\u00e8re apparemment chaotique dans le cristal puisse produire des figures aussi ordonn\u00e9es. L\u00e0 se trouve une des grandes beaut\u00e9s des lasers.<\/p>\n\n\n\n<p>Une r\u00e9alisation Art in physics, textes librement inspir\u00e9s des prises de vues au LENS et des photographies d\u2019Hippolyte Dupont.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Pour en savoir plus :<\/h4>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-9d6595d7 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<h5 class=\"wp-block-heading\">Pour comprendre les modes transverses<\/h5>\n\n\n\n<p>Une explication tr\u00e8s compl\u00e8te en anglais des modes transverses. <\/p>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-4-3 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe loading=\"lazy\" title=\"Laser fundamentals II: Laser transverse modes | MIT Video Demonstrations in Lasers and Optics\" width=\"880\" height=\"660\" src=\"https:\/\/www.youtube.com\/embed\/o1YjIyzshh8?start=9&#038;feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n<\/div><\/figure>\n<\/div>\n<\/div>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-9d6595d7 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<h5 class=\"wp-block-heading\">Vid\u00e9o sur un ph\u00e9nom\u00e8ne similaire : la corde vibrante<\/h5>\n\n\n\n<p>Un autre exemple de l&#8217;effet des conditions aux limites pour une onde stationnaire. <\/p>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe loading=\"lazy\" title=\"Ondes stationnaires\" width=\"880\" height=\"495\" src=\"https:\/\/www.youtube.com\/embed\/0bEwr0v4k_c?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n<\/div><\/figure>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Hors cadre &#8211; Mode d&#8217;\u00e9mission Un laser est en train d\u2019\u00eatre align\u00e9 dans une relative obscurit\u00e9. La pi\u00e8ce n\u2019a pas<\/p>\n<p><a href=\"https:\/\/www.artinphysics.fr\/index.php\/1264-2\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"><\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_vp_format_video_url":"","_vp_image_focal_point":[],"footnotes":""},"class_list":["post-1264","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.artinphysics.fr\/index.php\/wp-json\/wp\/v2\/pages\/1264","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.artinphysics.fr\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.artinphysics.fr\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.artinphysics.fr\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.artinphysics.fr\/index.php\/wp-json\/wp\/v2\/comments?post=1264"}],"version-history":[{"count":1,"href":"https:\/\/www.artinphysics.fr\/index.php\/wp-json\/wp\/v2\/pages\/1264\/revisions"}],"predecessor-version":[{"id":1267,"href":"https:\/\/www.artinphysics.fr\/index.php\/wp-json\/wp\/v2\/pages\/1264\/revisions\/1267"}],"wp:attachment":[{"href":"https:\/\/www.artinphysics.fr\/index.php\/wp-json\/wp\/v2\/media?parent=1264"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}