{"id":42294,"date":"2020-06-30T10:27:25","date_gmt":"2020-06-30T08:27:25","guid":{"rendered":"https:\/\/www.iemn.fr\/articles-temporaires\/these-mahmoud-abou-daher-realisation-et-optimisation-de-transistors-hemt-gan-forte-puissance-et-haute-frequence-par-technologie-de-transfert-de-couches-sur-substrat-hote-analyse-de-robustesse-com-2.html"},"modified":"2020-08-31T10:07:28","modified_gmt":"2020-08-31T08:07:28","slug":"these-mahmoud-abou-daher-realisation-et-optimisation-de-transistors-hemt-gan-forte-puissance-et-haute-frequence-par-technologie-de-transfert-de-couches-sur-substrat-hote-analyse-de-robustesse-com-2","status":"publish","type":"post","link":"https:\/\/www.iemn.fr\/en\/these\/these-mahmoud-abou-daher-realisation-et-optimisation-de-transistors-hemt-gan-forte-puissance-et-haute-frequence-par-technologie-de-transfert-de-couches-sur-substrat-hote-analyse-de-robustesse-com-2.html","title":{"rendered":"THESE : Martin MICICA \u2013 Mat\u00e9riaux \u00e0 base de cristaux mol\u00e9culaires pour laser t\u00e9rahertz \u00e0 l\u2019\u00e9tat solide"},"content":{"rendered":"<div id='layer_slider_1'  class='avia-layerslider main_color avia-shadow  avia-builder-el-0  el_before_av_heading  avia-builder-el-first  container_wrap sidebar_right'  style='height: 261px;'  ><div id=\"layerslider_58_6ay94yy3ek2\" data-ls-slug=\"homepageslider\" class=\"ls-wp-container fitvidsignore ls-selectable\" style=\"width:1140px;height:260px;margin:0 auto;margin-bottom: 0px;\"><div class=\"ls-slide\" data-ls=\"duration:6000;transition2d:5;\"><img loading=\"lazy\" decoding=\"async\" width=\"2600\" height=\"270\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1.jpg\" class=\"ls-bg\" alt=\"\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1.jpg 2600w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1-300x31.jpg 300w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1-768x80.jpg 768w, 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class='main_color av_default_container_wrap container_wrap sidebar_right'  ><div class='container av-section-cont-open' ><div class='template-page content  av-content-small alpha units'><div class='post-entry post-entry-type-page post-entry-42294'><div class='entry-content-wrapper clearfix'>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-kei7v83x-a0e8b620760c8a5fd27b73cf2c1ab69f\">\n#top .av-special-heading.av-kei7v83x-a0e8b620760c8a5fd27b73cf2c1ab69f{\nmargin:0 0 10px 0;\npadding-bottom:4px;\n}\nbody .av-special-heading.av-kei7v83x-a0e8b620760c8a5fd27b73cf2c1ab69f .av-special-heading-tag .heading-char{\nfont-size:25px;\n}\n.av-special-heading.av-kei7v83x-a0e8b620760c8a5fd27b73cf2c1ab69f .av-subheading{\nfont-size:15px;\n}\n<\/style>\n<div  class='av-special-heading av-kei7v83x-a0e8b620760c8a5fd27b73cf2c1ab69f av-special-heading-h2  avia-builder-el-1  el_after_av_layerslider  el_before_av_hr  avia-builder-el-first'><h2 class='av-special-heading-tag'  itemprop=\"headline\"  >THESE : Martin MICICA \u2013 Mat\u00e9riaux \u00e0 base de cristaux mol\u00e9culaires pour laser t\u00e9rahertz \u00e0 l\u2019\u00e9tat solide<\/h2><div class=\"special-heading-border\"><div class=\"special-heading-inner-border\"><\/div><\/div><\/div>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-18u73nj-dad6a947580930e400fc42ba200e80f1\">\n#top .hr.av-18u73nj-dad6a947580930e400fc42ba200e80f1{\nmargin-top:5px;\nmargin-bottom:5px;\n}\n.hr.av-18u73nj-dad6a947580930e400fc42ba200e80f1 .hr-inner{\nwidth:100%;\n}\n<\/style>\n<div  class='hr av-18u73nj-dad6a947580930e400fc42ba200e80f1 hr-custom  avia-builder-el-2  el_after_av_heading  el_before_av_textblock  hr-left hr-icon-no'><span class='hr-inner inner-border-av-border-thin'><span class=\"hr-inner-style\"><\/span><\/span><\/div>\n<section  class='av_textblock_section av-jriy64i8-2f4600354c0449b610997916bbd9b6bc'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" >\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-13ewzjw-68e036126b913e5028f77311dc66b825\">\n.av_font_icon.av-13ewzjw-68e036126b913e5028f77311dc66b825{\ncolor:#bfbfbf;\nborder-color:#bfbfbf;\n}\n.av_font_icon.av-13ewzjw-68e036126b913e5028f77311dc66b825 .av-icon-char{\nfont-size:60px;\nline-height:60px;\n}\n<\/style>\n<span  class='av_font_icon av-13ewzjw-68e036126b913e5028f77311dc66b825 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='\ue8c9' data-av_iconfont='entypo-fontello' ><\/span><\/span>\n<p><strong>Martin MICICA<\/strong><\/p>\n<p>Soutenance : 28 janvier 2020 \u00e0 14h00<strong><br \/>\n<\/strong>Nanotechnology Centre, Technical University of Ostrava,\u00a0 Poruba, Czech Republic<\/p>\n<\/div><\/section>\n<section  class='av_textblock_section av-jtefqx33-628129dba2299b2ecd65ebfc92eac29d'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><div  class='hr av-kjh3zw-4dff888f744b728a1aca9b3a0971493a hr-default  avia-builder-el-6  avia-builder-el-no-sibling'><span class='hr-inner'><span class=\"hr-inner-style\"><\/span><\/span><\/div>\n<h5><strong><span style=\"color: #800000;\">Jury :<\/span><\/strong><\/h5>\n<ul>\n<li>Jean-Fran\u00e7ois LAMPIN, Directeur de Recherche, Universit\u00e9 de Lille, Directeur de th\u00e8se<\/li>\n<li>Kamil POSTAVA, Associate Professor, VSB \u2013 Technical University of Ostrava, Directeur de th\u00e8se<\/li>\n<li>Mathias VANWOLLEGEM, Charg\u00e9 de Recherche, Universit\u00e9 de Lille, Examinateur<\/li>\n<li>Jarom\u00edr PI\u0161TORA, Professeur, VSB \u2013 Technical University of Ostrava, Examinateur<\/li>\n<li>Olivier PIRALI, Charg\u00e9 de Recherche, Universit\u00e9 Paris-Sud, Examinateur<\/li>\n<li>Huml\u00ed\u010dek JOSEF, Professeur, IEMN, Masaryk University, Rapporteur<\/li>\n<li>Sukhdeep DHILLON, Directeur de Recherche, \u00c9cole Normale Sup\u00e9rieure, Rapporteur<\/li>\n<li>Christelle KADLEC, Directeur de Recherche, Czech Academy of Sciences, Rapporteur<\/li>\n<\/ul>\n<h5>Summary:<\/h5>\n<p>Les progr\u00e8s de la technologie t\u00e9rahertz (THz) au cours des derni\u00e8res ann\u00e9es ont cr\u00e9\u00e9 une demande pour de nouvelles sources de rayonnement t\u00e9rahertz, indispensables pour utiliser pleinement son potentiel dans les applications quotidiennes. Cette th\u00e8se porte sur le sujet des sources t\u00e9rahertz, plus pr\u00e9cis\u00e9ment sur le d\u00e9veloppement de nouveaux lasers t\u00e9rahertz qui offriraient plus d\u2019efficacit\u00e9 et une meilleure accordabilit\u00e9 tout en \u00e9tant plus compacts.<\/p>\n<p>Pour atteindre cet objectif, nous avons choisi deux approches. La premi\u00e8re concerne l\u2019optimisation de la conception actuelle des lasers \u00e0 gaz mol\u00e9culaires \u00e0 pompage optique t\u00e9rahertz. Ce type de laser utilise g\u00e9n\u00e9ralement un laser infrarouge moyen \u00e0 d\u00e9charge CO2 comme pompe optique pour exciter les \u00e9tats ro-vibrationnels dans les gaz. Une pompe optique \u00e0 CO2 pr\u00e9sente de nombreux inconv\u00e9nients, notamment sa taille et un nombre limit\u00e9 de raies pouvant \u00eatre pomp\u00e9es optiquement. Ces deux inconv\u00e9nients peuvent \u00eatre r\u00e9solus par le remplacement du laser CO2 par un laser \u00e0 cascade quantique dans l\u2019infrarouge moyen, plus petit, plus efficace et pr\u00e9sentant une plus grande accordabilit\u00e9, ce qui permet un pompage r\u00e9sonant presque parfait d\u2019un gaz mol\u00e9culaire actif t\u00e9rahertz. Dans cet esprit, nous avons r\u00e9alis\u00e9 une s\u00e9rie d\u2019exp\u00e9riences \u00e9valuant les propri\u00e9t\u00e9s d\u2019amplification de gaz mol\u00e9culaires, principalement du NH3, lors du pompage optique par laser \u00e0 cascade quantique. De nouvelles raies lasers t\u00e9rahertz ont \u00e9t\u00e9 test\u00e9es avec succ\u00e8s. Le gain en un seul passage le plus \u00e9lev\u00e9 a \u00e9t\u00e9 observ\u00e9 pour la raie NH3 saQ(3,3) (1,073 THz) avec une valeur de 10,1 dB.m-1 (puissance de pompage de 63 mW), ce qui correspond \u00e0 la valeur la plus \u00e9lev\u00e9e report\u00e9e pour ce type de laser. De plus, des exp\u00e9riences suppl\u00e9mentaires ont \u00e9t\u00e9 r\u00e9alis\u00e9es \u00e0 l\u2019aide d\u2019un nouveau prototype de laser \u00e0 gaz mol\u00e9culaire pomp\u00e9 optiquement.<br \/>\nUne deuxi\u00e8me approche compl\u00e8tement novatrice consiste \u00e0 d\u00e9velopper un type de laser t\u00e9rahertz \u00e0 base de milieu \u00e0 l\u2019\u00e9tat solide pomp\u00e9 optiquement. L\u2019id\u00e9e est de pomper optiquement des modes de vibration dans des cristaux mol\u00e9culaires et d\u2019obtenir un changement de population des phonons de basse fr\u00e9quence. Les mat\u00e9riaux cristallins mol\u00e9culaires ont \u00e9t\u00e9 s\u00e9lectionn\u00e9s en tant que mat\u00e9riaux lasers potentiels en raison de leurs modes de vibration dans la gamme spectrale infrarouge moyen et t\u00e9rahertz. La spectroscopie infrarouge \u00e0 transform\u00e9e de Fourier et la spectroscopie dans le domaine temporel t\u00e9rahertz ont \u00e9t\u00e9 appliqu\u00e9es pour analyser le spectre vibratoire des cristaux mol\u00e9culaires choisis (sucres, acides organiques). Des monocristaux d\u2019acide L-tartrique ont \u00e9t\u00e9 pr\u00e9par\u00e9s et analys\u00e9s en d\u00e9tail afin d\u2019obtenir leurs fonctions optiques . \u00c0 la fin de ce travail, une exp\u00e9rience d\u2019\u00e9valuation du gain t\u00e9rahertz en milieu cristallin pomp\u00e9 optiquement est propos\u00e9e.<\/p>\n<h5>Abstract:<\/h5>\n<p>The progress in terahertz (THz) technology in the last years created a demand for new sources of terahertz radiation, which are required for utilization of its full potential in everyday applications. This thesis deals with the subject of terahertz sources and specifically the development of novel terahertz lasers which would provide more efficiency and better tunability in a more compact package.<\/p>\n<p>To carry out this objective we chose two approaches. The first is the optimization of existing terahertz optically pumped molecular gas laser design. This type of lasers typically utilizes a mid-infrared CO2 discharge laser as optical pump to excite roto-vibrational states in molecular gases. A CO2 optical pump has multiple drawbacks especially its size and a limited number of lines that can be optically pumped. Both drawbacks can be solved by the replacement of the CO2 laser by a mid-infrared quantum cascade laser, which is small, more efficient and continuously tunable, which allows almost perfect resonant pumping of a terahertz active molecular gas. With this in mind, we made a series of experiments evaluating lasing properties of molecular gases, mostly NH3, during optical pumping by a quantum cascade laser. New lasing lines were tested for terahertz gain with success. The highest single pass gain was observed on the NH3 line saQ(3,3) (1.073 THz) with the value of 10.1 dB.m-1 (63 mW pumping power), which is the highest reported value for this type of laser. Moreover, additional experiments were performed using a new prototype of terahertz optically pumped molecular gas laser.<\/p>\n<p>The second approach is the development of a completely new type of terahertz lasers based on optically pumped solid-state media. The idea is to optically pump vibrational modes in molecular crystals and to obtain a change of population on low frequency phonons. Molecular crystal materials were selected as a potential lasing material due to their vibrational modes in mid-infrared and terahertz spectral range. Fourier transform infrared spectroscopy and terahertz time domain spectroscopy were applied to analyze vibrational spectrum of the chosen molecular crystals (sugars, organic acids). Single crystals of L-tartaric acid were prepared, further analysed, and optical functions obtained. At the end of this work, the experiment for the evaluation of a terahertz gain in crystalline media during the optical pumping is proposed<\/p>\n<\/div><\/section>","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":[199],"tags":[],"class_list":["post-42294","post","type-post","status-publish","format-standard","hentry","category-these"],"_links":{"self":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/42294","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=42294"}],"version-history":[{"count":0,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/42294\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/media?parent=42294"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/categories?post=42294"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/tags?post=42294"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}