{"id":72040,"date":"2025-01-30T15:05:42","date_gmt":"2025-01-30T13:05:42","guid":{"rendered":"https:\/\/www.iemn.fr\/?p=72040"},"modified":"2025-02-25T09:57:37","modified_gmt":"2025-02-25T07:57:37","slug":"une-nouvelle-dimension-en-acoustique-picoseconde-2","status":"publish","type":"post","link":"https:\/\/www.iemn.fr\/en\/newsletter\/une-nouvelle-dimension-en-acoustique-picoseconde-2.html","title":{"rendered":"A new dimension in picosecond acoustics"},"content":{"rendered":"<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-m6j6ipl0-9a512153cbb6cd2e70da8c5e0c78c8c1\">\n#top .av-special-heading.av-m6j6ipl0-9a512153cbb6cd2e70da8c5e0c78c8c1{\npadding-bottom:10px;\ncolor:#b50000;\n}\nbody .av-special-heading.av-m6j6ipl0-9a512153cbb6cd2e70da8c5e0c78c8c1 .av-special-heading-tag .heading-char{\nfont-size:25px;\n}\n.av-special-heading.av-m6j6ipl0-9a512153cbb6cd2e70da8c5e0c78c8c1 .special-heading-inner-border{\nborder-color:#b50000;\n}\n.av-special-heading.av-m6j6ipl0-9a512153cbb6cd2e70da8c5e0c78c8c1 .av-subheading{\nfont-size:15px;\n}\n<\/style>\n<div  class='av-special-heading av-m6j6ipl0-9a512153cbb6cd2e70da8c5e0c78c8c1 av-special-heading-h2 custom-color-heading blockquote modern-quote modern-centered  avia-builder-el-0  el_before_av_textblock  avia-builder-el-first'><h2 class='av-special-heading-tag'  itemprop=\"headline\"  >A new dimension in picosecond acoustics<\/h2><div class=\"special-heading-border\"><div class=\"special-heading-inner-border\"><\/div><\/div><\/div>\n<section  class='av_textblock_section av-m6j7q3j8-f0a79c8c993a0bd14946be5da4341769'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p><a href=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/01\/montage_nanoson5.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-72034 size-full\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/01\/montage_nanoson5.jpg\" alt=\"\" width=\"2000\" height=\"102\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/01\/montage_nanoson5.jpg 2000w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/01\/montage_nanoson5-300x15.jpg 300w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/01\/montage_nanoson5-1030x53.jpg 1030w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/01\/montage_nanoson5-768x39.jpg 768w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/01\/montage_nanoson5-1536x78.jpg 1536w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/01\/montage_nanoson5-18x1.jpg 18w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/01\/montage_nanoson5-1500x77.jpg 1500w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/01\/montage_nanoson5-705x36.jpg 705w\" sizes=\"auto, (max-width: 2000px) 100vw, 2000px\" \/><\/a><\/p>\n<\/div><\/section>\n<div  class='flex_column av-oycd3h-9310b11ef030ae96b42b55c7bd8b6468 av_one_half  avia-builder-el-2  el_after_av_textblock  el_before_av_one_half  first flex_column_div  column-top-margin'     ><style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-m6j6i7e2-dc5fe49bf194199c51685ae09f0c4698\">\n#top .av_textblock_section.av-m6j6i7e2-dc5fe49bf194199c51685ae09f0c4698 .avia_textblock{\ntext-align:justify;\n}\n<\/style>\n<section  class='av_textblock_section av-m6j6i7e2-dc5fe49bf194199c51685ae09f0c4698'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><div id=\"attachment_72029\" style=\"width: 510px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/01\/croquis_arnaud2.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-72029\" class=\"wp-image-72029\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/01\/croquis_arnaud2.jpg\" alt=\"\" width=\"500\" height=\"361\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/01\/croquis_arnaud2.jpg 1500w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/01\/croquis_arnaud2-300x217.jpg 300w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/01\/croquis_arnaud2-1030x744.jpg 1030w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/01\/croquis_arnaud2-768x555.jpg 768w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/01\/croquis_arnaud2-18x12.jpg 18w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/01\/croquis_arnaud2-705x509.jpg 705w\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" \/><\/a><p id=\"caption-attachment-72029\" class=\"wp-caption-text\">Picosecond acoustics in a transparent thin film: a metal film is excited by a femtosecond laser pulse, an ultra-high-frequency acoustic pulse passes through the film and an oscillation is detected. The two signals are obtained with a standard film (black curve) and a tilted film (red curve). The Fourier transform visible on the right confirms that two acoustic frequencies are detected with the tilted film: transverse and longitudinal waves.<\/p><\/div>\n<p><strong><span style=\"color: #006278;\"><a href=\"https:\/\/www.nature.com\/articles\/s41598-024-53082-4\" target=\"_blank\" rel=\"noopener\"><span style=\"color: #ff7b00;\"><span style=\"color: #008080;\">\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-mqde7m-c95ffd3c85dc0a6a771b1f41c40fa860\">\n.av_font_icon.av-mqde7m-c95ffd3c85dc0a6a771b1f41c40fa860{\ncolor:#006278;\nborder-color:#006278;\n}\n.av_font_icon.av-mqde7m-c95ffd3c85dc0a6a771b1f41c40fa860 .av-icon-char{\nfont-size:25px;\nline-height:25px;\n}\n<\/style>\n<span  class='av_font_icon av-mqde7m-c95ffd3c85dc0a6a771b1f41c40fa860 avia_animate_when_visible av-icon-style- avia-icon-pos-left avia-icon-animate'><span class='av-icon-char' aria-hidden='true' data-av_icon='\ue889' data-av_iconfont='entypo-fontello' ><\/span><\/span><\/span><\/span><\/a>A team from the Institute of Electronics, Microelectronics and Nanotechnology in collaboration with FEMTO-ST in Besan\u00e7on and LMI in Lyon (Laboratoire des multimat\u00e9riaux et interfaces) has extended the metrological capabilities of picosecond acoustics. This laser technique makes it possible to measure the elastic properties of thin films, but until now only in the direction perpendicular to the layer. Thanks to a metal layer made of inclined columns, in-plane elasticity also becomes accessible.\u00a0 The results have been published in the journal Applied Physics Letters.\u00a0<\/span><\/strong><\/p>\n<p>Picosecond acoustics refers to ultra-high-frequency acoustics that produce hypersound (far beyond ultrasound), which is of course no longer heard, but which is very useful for measuring the properties of thin films and other nanostructures. The technique first saw the light of day in the 1980s, and since then has become as popular in the academic world as it is in industry, where it is used to control microprocessors on production lines. To access the world of hyper or \u201cnanosounds\u201d, there are no microphones or transducers, just laser light delivered in extremely brief flashes, femtosecond pulses.<\/p>\n<\/div><\/section><\/div>\n<div  class='flex_column av-tsystp-ac90398b8538b879ca47dccffe941adc av_one_half  avia-builder-el-5  el_after_av_one_half  avia-builder-el-last  flex_column_div  column-top-margin'     ><p>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-m6jcczt7-f8046806a4abff40588d34267132fedb\">\n#top .hr.hr-invisible.av-m6jcczt7-f8046806a4abff40588d34267132fedb{\nheight:80px;\n}\n<\/style>\n<div  class='hr av-m6jcczt7-f8046806a4abff40588d34267132fedb hr-invisible  avia-builder-el-6  el_before_av_textblock  avia-builder-el-first'><span class='hr-inner'><span class=\"hr-inner-style\"><\/span><\/span><\/div><br \/>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-m6j6najf-4b93c102b925605a8cdce0f2f786a9b2\">\n#top .av_textblock_section.av-m6j6najf-4b93c102b925605a8cdce0f2f786a9b2 .avia_textblock{\ntext-align:justify;\n}\n<\/style>\n<section  class='av_textblock_section av-m6j6najf-4b93c102b925605a8cdce0f2f786a9b2'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p>But this technique has an intrinsic limitation: only certain acoustic waves are accessible, namely longitudinal waves. And this is a problem, because we learn much more about the state of matter when we measure the speed of several types of wave (longitudinal and transverse). Previous work has shown that it is sometimes possible to get around this limitation, but always in specific sample configurations. In particular, it was impossible to generalize to thin-film samples on silicon, THE basic geometry for applications, so these attempts were in vain.<\/p>\n<blockquote>\n<p><strong>Using a thin metallic layer deposited in inclined columns, we have shown that any transparent layer on silicon can be characterized in terms of longitudinal and transverse waves. The inclined layer acts as a mixed longitudinal\/transverse emitter when subjected to the laser, and picosecond acoustics gain a new dimension.<\/strong> Although the study was initially dedicated to transparent thin films, such as silica, aluminum nitride and silicon carbide, the process is now being extended to non-transparent layers, such as metallic layers. The applications are numerous, since measuring the elastic properties of thin films is essential in the design of technological objects as varied as filters for mobile telephony, space mirrors, intelligent glass&#8230;<\/p>\n<\/blockquote>\n<p><strong>R\u00e9f\u00e9rence<\/strong><br \/>\n<em>Tilted columnar metal film as transducer of transverse coherent acoustic phonons in Picosecond Acoustics.<\/em><br \/>\n<em> Asma Chargui, Nicolas Martin, Gabriel Ferro, et Arnaud Devos.<\/em><br \/>\n<em> Applied Physics Letters,\u00a08 novembre 2024.<\/em><br \/>\n<a href=\"https:\/\/doi.org\/10.1063\/5.0228331\" target=\"_blank\" rel=\"noopener\"><em> https:\/\/doi.org\/10.1063\/5.0228331<\/em><\/a><\/p>\n<\/div><\/section><br \/>\n<section  class='av_textblock_section av-m6j73job-367cc9634111588a80d23ae1ad07b845'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><div><div  class='avia-button-wrap av-rpqvoq-62216f8d0422b5d2931cc59a1713615e-wrap avia-button-left  avia-builder-el-9  avia-builder-el-no-sibling'><a href='mailto:arnaud.devos@iemn.fr'  class='avia-button av-rpqvoq-62216f8d0422b5d2931cc59a1713615e av-link-btn avia-icon_select-yes-left-icon avia-size-light avia-position-left avia-color-silver'   aria-label=\"Arnaud Devos\"><span class='avia_button_icon avia_button_icon_left' aria-hidden='true' data-av_icon='\ue805' data-av_iconfont='entypo-fontello'><\/span><span class='avia_iconbox_title' >Arnaud Devos<\/span><\/a><\/div><\/div>\n<div><\/div>\n<\/div><\/section><\/p><\/div>","protected":false},"excerpt":{"rendered":"","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[297],"tags":[],"class_list":["post-72040","post","type-post","status-publish","format-standard","hentry","category-newsletter"],"_links":{"self":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/72040","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/comments?post=72040"}],"version-history":[{"count":0,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/72040\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/media?parent=72040"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/categories?post=72040"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/tags?post=72040"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}