{"id":199,"date":"2025-08-27T20:06:07","date_gmt":"2025-08-27T11:06:07","guid":{"rendered":"https:\/\/www.hulinks.co.jp\/en\/?page_id=199"},"modified":"2025-11-07T15:13:02","modified_gmt":"2025-11-07T06:13:02","slug":"needle-tunneling","status":"publish","type":"page","link":"https:\/\/www.hulinks.co.jp\/en\/tfcalc\/special-features\/needle-tunneling\/","title":{"rendered":"Needle\/Tunneling Optimization"},"content":{"rendered":"\n<h1 class=\"wp-block-heading is-style-nostyle\">Focus on Special Features<\/h1>\n\n\n\n<h2 class=\"wp-block-heading is-style-bottomline\">Needle\/Tunneling Optimization<\/h2>\n\n\n\n<p>When needle optimization finds an \u201coptimal\u201d design, that design may still not have the desired performance. Needle optimization has merely found a local minimum of the merit function.<\/p>\n\n\n\n<p>The purpose of the tunneling method is to find another \u2014 better \u2014 local minimum. It does this by growing a layer \u2014 which has the effect of tunneling to another valley of the merit function. See the diagram below for a 2-layer example.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"334\" height=\"305\" src=\"https:\/\/www.hulinks.co.jp\/en\/wp-content\/uploads\/sites\/2\/software\/tfcalc\/tf_needle_1.gif\" alt=\"\" class=\"wp-image-200\"\/><\/figure><\/div>\n\n\n<p>The arrow indicates how this method tunneled from one valley to another.<\/p>\n\n\n\n<p>A benefit of the needle\/tunneling method is that the initial design can be very simple \u2014 perhaps only 1 QWOT thick. The method will grow the design to meet the desired performance.<\/p>\n\n\n\n<p>Another benefit is that a sequence of designs is created, giving the designer a choice of designs to manufacture.<\/p>\n\n\n\n<p>Finally, this method excels at finding the thinnest design that meets a given performance specification; it just grows the design until the requirement is attained. For an example of this, see\u00a0<a href=\"https:\/\/www.hulinks.co.jp\/en\/tfcalc\/examples\/list-of-coating-design\/growing-antireflection\/\" data-type=\"page\" data-id=\"289\">Growing an Antireflection Coating<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Focus on Special Features Needle\/Tunneling Optimization When needle optimization finds an \u201coptimal\u201d design, that design may still not have the desired performance. Needle optimization has merely found a local minimum of the merit function. The purpose of the tunneling method is to find another \u2014 better \u2014 local minimum. It does this by growing a&#8230;<\/p>\n","protected":false},"author":15,"featured_media":0,"parent":70,"menu_order":5,"comment_status":"closed","ping_status":"closed","template":"liquid.php","meta":{"footnotes":""},"tags":[],"class_list":["post-199","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/pages\/199","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/users\/15"}],"replies":[{"embeddable":true,"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/comments?post=199"}],"version-history":[{"count":4,"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/pages\/199\/revisions"}],"predecessor-version":[{"id":948,"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/pages\/199\/revisions\/948"}],"up":[{"embeddable":true,"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/pages\/70"}],"wp:attachment":[{"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/media?parent=199"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.hulinks.co.jp\/en\/wp-json\/wp\/v2\/tags?post=199"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}