{"id":392234,"date":"2017-04-03T02:00:00","date_gmt":"2017-04-02T23:00:00","guid":{"rendered":"http:\/\/www.fyysika.ee\/?guid=2b577580b698735b80e79883901a282b"},"modified":"2017-04-03T02:00:00","modified_gmt":"2017-04-02T23:00:00","slug":"waves-and-rays-in-plano-concave-laser-cavities-i-geometric-modes-in-the-paraxial-approximation","status":"publish","type":"post","link":"https:\/\/www.fyysika.ee\/?p=392234","title":{"rendered":"Waves and rays in plano-concave laser cavities: I. Geometric modes in the paraxial approximation"},"content":{"rendered":"<p>Eigenmodes of laser cavities are studied theoretically and experimentally in two companion papers,<br \/>\nwith the aim of making connections between undulatory and geometric properties of light. In this<br \/>\nfirst paper, we focus on macroscopic open-cavity lasers with localized gain. The model is based on<br \/>\nthe wave equation in the paraxial approximation; experiments are conducted with a simple<br \/>\ndiode-pumped Nd:YAG laser with a variable cavity length. After recalling fundamentals of laser beam<br \/>\noptics, we consider plano-concave cavities with on-axis or off-axis pumping, with emphasis put on<br \/>\ndegenerate cavity lengths, where modes of different order resonate at the same frequency, and<br \/>\ncombine to form surprising transverse beam profiles. Degeneracy leads to the oscillation of<br \/>\nso-called geometric modes whose properties can be understood, to a certain extent, also within a ray<br \/>\noptics picture. We first provide a heuristic description of these modes, based on geometric<br \/>\nreasoning, and then show &#8230;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Eigenmodes of laser cavities are studied theoretically and experimentally in two companion papers,<br \/>\nwith the aim of making connections between undulatory and geometric properties of light. In this<br \/>\nfirst paper, we focus on macroscopic open-cavity laser&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_genesis_hide_title":false,"_genesis_hide_breadcrumbs":false,"_genesis_hide_singular_image":false,"_genesis_hide_footer_widgets":false,"_genesis_custom_body_class":"","_genesis_custom_post_class":"","_genesis_layout":"","footnotes":""},"categories":[178],"tags":[],"class_list":{"0":"post-392234","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-rss-fuusikaharidus","7":"entry"},"_links":{"self":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/392234","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=392234"}],"version-history":[{"count":0,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/392234\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=392234"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=392234"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=392234"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}