A. Maker Annenberg Vakfı Doktora Araştırma Bursu tarafından desteklenen ve bu çalışma, Ulusal Bilim Vakfı [085.281 ve 1.028.440] tarafından desteklenmiştir.

1. Microsphere Fabrikasyon <ol><li> Bir ucundan optik lif, şerit ~ 1.5 &#39;kaplama küçük bir miktarda (yaklaşık 5 inç) seçmek ve metanol veya etanol (Şekil 1a, b) aşağıdakilerin ikisinden biri ile temizlenir. </li><li> Bir fiber optik satırla Varsa, çatlatma sonu. Mevcut değilse, tel kesme veya ~ 0.5 &quot;bırakılır böyle makasla kesti. Bir fiber optik cleaver kullanmanın avantajı Şekil 1b olarak çok düzgün, düzgün kesme üretmesidir. Bir kesiden Aşırı pürüzler veya kusurlarına neden olabilir Ortaya çıkan kürelerin kalite faktörü düşürücü düzensiz akar. </li><li> Için bir ~ 500uM çapı spot büyüklüğü odaklı CO2 lazer gücü 3W temizlenmiş fiber sonuna Açığa ~ 1 saniye (Şekil 1c, d, e). Bu çapa küreler ~ 200μm üretir; Bununla birlikte, boyutu fiber optiğin çapı artan ya da azalan tarafından ayarlanabilir. Biraz b de lazer yoğunluğu olabilir ayarlayarakakıtacak daha büyük veya daha küçük küreler için gerekli e. </li></ol> 2. Microtoroid Fabrikasyon <ol><li> Tasarım ve seçtiğiniz aralığı ve çapı, karanlık, katı daireli bir photomask olun. Bu üretilen toroidler maske daireler 25-30% daha küçük olacağını dikkate almak önemlidir. Örneğin, 100 mikron arasında bir çapa sahip katı bir daire yaklaşık 75 mikron arasında bir çapa sahip bir toroid üretecektir. Ayrıca, her bir daire arasında ve uzayın en az 5mm çevrelerin diziler arasında ve maske kenarlarında boşluk en az 1-2mm bırakmanız önerilir. Örnek gofret dikkatlice cımbız ile ele alınması gerektiğinden, bu toroidler zarar vermeden kavrama cımbız için alan bırakmak önemlidir. Ayrıca, ilave alan nihai cihazlar içine çift ışık konik bir optik lif için oda sağlar, ve numuneler daha kolay bir şekilde daha küçük dizileri halinde kesilmesini sağlar. Bu işlem için, biz 160 mikron di sıraları ile bir maske kullanılırçevrelerin her satır arasındaki boşluk ~ 5mm ile ayrı ameter daireler ~ 1mm. Bitmiş toroidler çapı yaklaşık 110 mm&#39;dir. </li><li> Termal yetiştirilen bir silika 2 mikron kalınlığında bir tabaka ile silikon gofret ile başlayın. Cleave gofret fotolitografi maskesi üzerinde istenilen microdisk kalıplarına uydurmak için, ışığa dayanıklı kenar boncuk yer bırakarak. Fabrikasyon başında, genellikle silikon yonga plakalarının daha büyük parçaları (~ birkaç cm x kaç cm) çevrelerin etch çeşitli diziler için en uygun olduğunu unutmayın. Büyük gofret fotolitografi ve bir defada daha fazla numune aşınmasından BOE, izin ve daha kolay cımbız ile işlenir. Daha sonra, XeF 2 aşındırma aşamasından önce, daha hızlı, daha düzgün XeF 2 dağlama izin çatlatma küçük diziler içinde büyük gofret tavsiye edilir. </li><li> Bir fumehood olarak, aseton, metanol, izopropanol ve deiyonize su ile durulanması ile gofret iyice temizlenir. Örnekleri bir azot veya filtrelenmiş ait kullanarak kurutun üfleyinressed hava tabancası ve sıcak bir tabağa yerleştirin kuruması için en az 2 dakika boyunca 120 ° C olarak ayarlanır. </li><li> Gofret serin icar sonra, bir çözücü / yanıcı fumehood yerleştirin ve buhar biriktirme yöntemi kullanılarak 2 dakika HMDS maruz. Basit bir buhar biriktirme yöntemi: Küçük bir 10ml beherdeki HMDS&#39;nin birkaç damla damlatın ve sonra buharı tutmak için büyük bir cam kap ile gofret ve küçük ölçek kapsamaktadır. </li><li> Uygun boyutta bir montaj ile bir değer bir örnek koyun. Bir damlalıklı şişe veya şırınga ve filtre kullanarak, örnek rezist geçerlidir. 3000rpm az 45 saniye takip 500rpm az 5 saniye, her numune üzerine kat S1813 fotorezist Spin. Gofret kenarı boncuk desen karışmaz böylece yeterince büyükse Kenar boncuk çıkarılması gerekli değildir. </li><li> Yumuşak fırında 95 azından bir sıcak plaka üzerinde ışığa ° C de 2 dakika. </li><li> UV maske hizalama ve istenilen photomask kullanarak, için heba kaplı örnekleri ortayaUV radyasyon 80mJ/cm 2 toplam. </li><li> UV ışınlarına maruz kalmış ışığa çıkarmak için MF-321 geliştirici örnekleri daldırın. Gelişmekte iken fotorezist gofret kaldırılır ve çözünmüş olarak, yakından izliyorum. Bu ışığa üniform kaldırılır sağlamak için bu işlem sırasında sürekli olarak swish / kabı karıştırılmaya önemlidir. Verilen parametreler için, ışığa yaklaşık 30 saniye geliştirmek için alır. </li><li> En istenmeyen fotorezist geliştiricisi çözünmüş zaman, akan su altında iyice durulayın örnekleri, hafifçe bir azot veya hava tabancası kullanarak örnekleri kurutma makinesiyle kurutabilir ve tüm istenmeyen fotorezist kaldırıldı sağlamak için bir mikroskop ile inceleyecektir. Gerekirse, örnekler geliştirici tekrar dalmış olabilir, ancak bir arzu fotorezist desenleri de zarar verebileceğinden örnekleri overdevelop için dikkatli olmalıdır. Istenilen desen hasarlı veya kusurlu ise (, heba olabiliraseton ve adımları 2,1-2,9) tekrar tekrar edilebilir ile kaldırıldı. </li><li> Geliştirdikten sonra, iyice akan su örneklerde yıkayın, hafifçe kurulayın örnekleri darbe ve sabit 110 sıcak bir tabağa fırında 2 dakika ° C. Bu adım, gelişmekte işlemi sırasında ışığa ve kısmen tamir pürüzlülüğü Yeniden akıtılan, onun cam geçiş sıcaklığı yukarıda fotorezist ısıtır. </li><li> Teflon kaplarda ve gerekli koruyucu ekipman kullanımı, geliştirilmiş tamponlanmış oksit asitlenmesi (BOE) örneklerde batırmayın. BOE silikon (Şekil 2a-c) dairesel silika yastıkları oluşturmak için ışığa kapsamında değildir silika etches HF içerir. Geliştirilmiş tamponlu HF çıkan silika çevrelerinde düzgün bir aşındırma, minimize pürüzlülüğü üretir. O HF% 49 HF ile başlayan tamponlu karıştırmak için mümkün olsa da, bu tipik olarak sadece küçük miktarlarda yapılan son derece değişken sonuçlara yol açabilir. </li><li> Yaklaşık 15-20 dakika (d sonrakalıpları, örnek boyutları ve numune sayısı) üzerine epending, teflon cımbız kullanarak BOE gelen örnekleri çıkarın. Dikkatle su, çalışan örnekleri durulayın. Örnekleri hidrofobik olunca silika kaldırılmıştır. </li><li> , Yakma durulama ve numuneler kurutulduktan sonra, optik bir mikroskop kullanarak onları kontrol edin. Istenilen desen tamamen kazınmış olan ve istenmeyen tüm silika kaldırılmıştır emin olun. Gerekirse, daha fazla gravürü için BOE için örnekleri dönün. Bir örnek overetch için dikkatli olmalı, ya da ışığa altında dairesel model hasar görebilir. </li><li> Bir kez BOE aşındırma tamamlandığında, iyice deiyonize su örnekleri durulayın ve kurulayın darbe. Örnekleri silikon büyük parça üzerinde ise, o da onları (bir dicing testere veya elmas çizici kullanarak) silika çevrelerin tek tek satırları daha küçük parçalar halinde kesilmiş tavsiye edilir. Çevrelerin Bireysel satır XeF daha hızlı ve düzgün kazınmış olan2 aşındırma adım (2.16). Kesme tarafından üretilen silikon toz sonraki adımda temizlik sırasında kaldırılır. </li><li> Aseton, metanol, izopropanol ve deiyonize su ile durulanması ile ışığa kaldırmak ve en az 2 dakika boyunca 120 ° C&#39;de sıcak plaka üzerinde, bir nitrojen tabanca ve ısıtma kullanılarak örnek kurutun. </li><li> Bir XeF 2 etcher kullanılarak, silika microdisks (Şekil 2B-f) oluşturmak üzere, dairesel silika pedler altında silikon undercut. Kazınmış miktarda elde microdisk en direği olarak optik bir mikroskop ile inceleme ile belirlenen toplam disk çapı, yaklaşık 1/3-1/2 olacak şekilde, yaklaşık 1/3 silika çemberin büyüklükte olmalıdır. XeF 2 darbelerinin sayısı ve her darbenin süresi haznesi ve kullanılan XeF 2 etcher tipinde silikon miktarına bağlı olarak değişir. </li><li> XeF 2 aşındırma sonra, yaklaşık 1 odaklanmış bir CO2 lazer ışınına maruz örnekleri~ 3 saniye ya da pürüzsüz toroid kadar 2W yoğunluğu (2g-i Şekil) oluşur. Diskin tam boyut ve XeF 2 miktarı undercut, biraz daha yüksek veya daha düşük bir yoğunluğu ve maruz kalma süresine bağlı olarak, bir microtoroid oluşturmak için gerekli olabilir. Bu silika microdisk düz, dairesel microtoroid oluşturacak şekilde, lazer ışını ve microdisk merkezinde hizalanmış olması önemlidir. </li></ol> 3. Temsilcisi Sonuçlar Mikroküre ve microtoroid aygıtları, optik mikroskop ve taramalı elektron mikroskobu (Şekil 1d, e ve Şekil 2h, i) hem kullanılarak görüntülenebilir. Tüm görüntüler, cihaz yüzeyinin bütünlüğü açıkça bellidir. Ayrıntılı bir yaklaşım ultra-yüksek-Q cihazlar oluşturur doğrulamak için, biz de bir çizgi kalınlığı (Δλ) ölçümü yapan ve yüklü hesaplayarak çeşitli aygıtları Q faktörü karakterizeSoru basit bir ifade ile: Q = λ / Δλ = ωτ, burada λ = rezonans dalga boyu, ω = frekans ve τ = foton ömrü. Daha önce ayrıntılı prosedürler 1,9 ve çeşitli cihazların bir karşılaştırma grafiği kullanılarak üretilen her aygıt için temsili spektrumları Şekil 3 &#39;de gösterilmiştir. Tüm cihazların kalite faktörleri çoğunluğu 100 milyon üzerinde olması ile, yukarıda 10 milyon vardır. Mikroküre spektrumu hafif saat yönünde veya saat yönünün tersine yayılan optik modu birine birleştiğinde belirten tek bir rezonans oldu. Ancak, toroid spektrumu aynı anda saat yönünde ve saat yönünün tersine modları içine birleştiğinde o ışık gösteren, bölünmüş bir rezonans sergiledi. Kaplin yerinde hafif bir kusur olduğunda bu olay meydana gelir. Bir çift-Lorentz için tayfı takılması ile, iki moddan Q faktörü tespit edilebilir. Bölünmüş rezonans fenomenna küre ve toroid rezonatörler hem de oluşabilir, ancak kusurları daha duyarlıdırlar ve küre göre daha az optik modlar olduğu gibi daha sık toroidler görülmektedir. <img src="/files/ftp_upload/4164/4164fig1.jpg" alt="Şekil 1"/> Mikroküre boşluğu üretim süreci Şekil 1. Akış çizelgesi. a) Rendering ve bir temizlenmeli ve parçalanabilen fiber optik b) optik mikrografı. c) Rendering, d) optik mikroskop ve e) rezonatör bir microspere elektron mikroskobu tarama. <img src="/files/ftp_upload/4164/4164fig2.jpg" alt="Şekil 2"/> Microtoroid boşluğu üretim süreci Şekil 2. Akış çizelgesi. a) Rendering, b) üst görünüm optik mikrograf ve c) fotolitografi ve BOE gravür tarafından tanımlanan dairesel oksit yüzeyi, elektron mikroskobu tarama yan görünümü. BOE oluşturduğu oksit hafif bir kama şeklinde not edin. d) Rendering, e) üst görünümoptik mikrograf ve f) XeF 2 aşındırma aşamasından sonra oksit pad elektron mikroskobu tarama yan görünümü. Oksit diski kama şekilli periferi muhafaza dikkat ediniz. microtoroid boşluğuna elektron mikroskobu tarama g) Rendering, h) üst görünüm optik mikrograf ve i) yan görünümü. <img src="/files/ftp_upload/4164/4164fig3.jpg" alt="Şekil 3"/> Şekil 3. A) mikroküre ve çizgi kalınlığı ölçüm yöntemi kullanılarak belirlenen b) microtoroid rezonans kaviteler Temsilcisi kalite faktörü spektrumları. Çok yüksek Q cihazlar, bir ışık, küçük bir defekt yansıyan ve saat yönünde ve saat yönünün tersine her iki yönde dolaşır olduğu, mod-bölme veya bir çift tepe gözlemleyebiliriz. c) Birkaç mikroküre ve microtoroid rezonans boşluklarının Q faktörleri gösteren Karşılaştırma grafiği. <a href="http://www.jove.com/files/ftp_upload/4164/4164fig3large.jpg" target="_blank">büyük rakam için buraya tıklayın</a> . Şekil 4. CO2 lazer reflow şematik set-up. CO 2 lazer ışını (katı mavi çizgi) yansır ve örnek odaklanmıştır. Bu 10.6 mikron / 10.6 mikron iletir ve 633 nm yansıtan 633 nm ışın birleştirici, geçer. Kiriş birleştiricinin off örnek optik sütun görüntüleri yansıması, bu nedenle görüntü biraz kırmızı. Bu kurulum için gerekli olan parçaların bir listesi Tablo 4&#39;te yer almaktadır. <img src="/files/ftp_upload/4164/4164fig5.jpg" alt="Şekil 5,"/> Şekil 5. Yanlış a) mikroküre ve b) microtoroid rezonans kaviteler reflowed. Demeti içinde yanlış yerleşimi nedeniyle, cihaz mal-oluşmuştur. c) bir düşük photomask ya da zayıf litografya bir sonucu olarak, toroid ay şekilli olup.

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Çıkar çatışması ilan etti.

Herhangi bir optik yapısı olduğu gibi, üretim sürecinin her aşamasında temiz tutmak önem taşımaktadır. Litografi ve uydurmalarla konuda yazılmış çok sayıda kitap var gibi, aşağıdaki önerileri kapsamlı olmalı, ancak araştırmacılar karşılaştıkları daha yaygın sorunları birkaç vurgulamak için değildir. 19-20 Microtoroid çevresindeki bir homojenlik başlangıç ​​diskin yeknesaklık göre belirlenmesinden dolayı, bu kalıp çok dairesel disk i?...

<table border="1"><tbody><tr><td> Bölümünün adı </td><td> Şirket </td><td> Katalog numarası </td><td> Yorumlar </td></tr><tr><td> Fiber scribe </td><td> Newport </td><td> F-RFS </td><td> Isteğe bağlı </td></tr><tr><td> Fiber optik </td><td> Newport </td><td> F-SMF-28 </td><td> Optik lif herhangi bir tür kullanılabilir. </td></tr><tr><td> Fiber kaplama striptizci </td><td> Newport </td><td> F-STR-175 </td><td> Tel soyucu de kullanılabilir </td></tr><tr><td> Etanol </td><td> Herhangi bir satıcı </td><td> Solvent seviyesi saflık </td><td> Metanol veya izopropanol ikamelerdir </td></tr></tbody></table> Tablo 1. Microsphere Fabrikasyon Malzeme. <table border="1"><tbody><tr><td> Reaktif Adı </td><td> Şirket </td><td> &lt;strong&gt; Katalog numarası </td><td> Yorumlar </td></tr><tr><td> 2μm termal yetiştirilen silika ile Silikon gofret </td><td> WRS Malzemeleri </td><td> n / a </td><td> Biz içsel 8, &lt;100&gt;, 4 &quot;çap kullanılabilir </td></tr><tr><td> HMDS (heksametildisilazan) </td><td> Aldrich </td><td> 440191 </td><td></td></tr><tr><td> Rezist </td><td> Shipley </td><td> S1813 </td><td></td></tr><tr><td> Geliştirici </td><td> Shipley </td><td> MF-321 </td><td></td></tr><tr><td> Geliştirilmiş - HF Tamponlu </td><td> Transene </td><td> n / a </td><td> Geliştirilmiş tamponlanmış HF düz BOE veya HF daha etch daha pürüzsüz, daha iyi kalite verir </td></tr><tr><td> Aseton, metanol, izopropanol </td><td> Herhangi bir satıcı </td><td> % 99.8 saflıkta </td><td></td></tr></tbody></table> Tablo 2. MICRotoroid Fabrikasyon Malzeme. <table border="1"><tbody><tr><td> Ekipman Adı </td><td> Üretici </td><td> Katalog numarası </td><td> Yorumlar </td></tr><tr><td> Spinner </td><td> Solitec </td><td> 5110-ND </td><td> Herhangi bir spinner kullanılabilir. </td></tr><tr><td> Aligner </td><td> Süß Microtec </td><td> MJB 3 </td><td> Herhangi bir hizalama kullanılabilir. </td></tr><tr><td> XeF 2 yakıcısı </td><td> Gelişmiş Haberleşme Devices, Inc </td><td> # ADCETCH2007 </td><td></td></tr></tbody></table> Tablo 3. Microtoroid İmalat Ekipmanları. <table border="1"><tbody><tr><td> Bölümünün adı </td><td> Şirket </td><td> Katalog numarası </td><td> Yorumlar </td></tr><tr><td> CO 2 </sub&gt; Lazer </td><td> Synrad </td><td> Series 48 </td><td></td></tr><tr><td> 3-Eksen aşamasında </td><td> OptoSigma </td><td> 120-0770 </td><td> Hem de diğer üreticilerin mevcuttur. </td></tr><tr><td> Si Reflektör 1 &quot;çap) </td><td> II-VI </td><td> 308325 </td><td> Hem de diğer üreticilerin mevcuttur. </td></tr><tr><td> Kinematik gimbal montaj (Si reflektör için) </td><td> Thor Labs </td><td> KX1G </td><td> Hem de diğer üreticilerin mevcuttur. </td></tr><tr><td> Işın birleştirici (1 &quot;çap) </td><td> Meller Optik </td><td> L19100008-B0 </td><td> Hem de diğer üreticilerin mevcuttur. </td></tr><tr><td> 4 &quot;Odak uzunluğu Lens (1&quot; çap) </td><td> Meller Optik veya II-VI </td><td></td><td> Gibi başka satıcılardan alınabilen yanı </td></tr><tr><td> Çeşitli mesaj, objektif bağlar </td><td> Thor Labs, Newport, Edmund Optik veya Optosigma </td><td></td><td></td></tr><tr><td> Yakınlaştırma 6000 makine görme sistemi </td><td> Navitar </td><td> n / a </td><td> Gerçek zamanlı görüntüleme için jenerik USB kamera ve bilgisayar gerektirir. Bu bir kit olarak satın alınmaktadır. </td></tr><tr><td> Yakınlaştırma 6000 sistemi için Focuser </td><td> Edmund Optik </td><td> 54-792 </td><td> Hem de diğer üreticilerin mevcuttur. </td></tr><tr><td> Yakınlaştırma 6000 XZ Eksen Pozisyonerler </td><td> Parker Daedal </td><td> CR4457, CR4452, 4499 </td><td> CR4457 X-ekseni ise, CR4452 Z ekseni ise, 4499 dirseği monte edilir. </td></tr></tbody></table> Tablo 4. CO 2 Lazer Reflow Set-up.

fabrication of silica ultra high quality factor microresonators

Whispering gallery resonant cavities confine light in circular orbits at their periphery.1-2 The photon storage lifetime in the cavity, quantified by the quality factor (Q) of the cavity, can be in excess of 500ns for cavities with Q factors above 100 million. As a result of their low material losses, silica microcavities have demonstrated some of the longest photon lifetimes to date1-2. Since a portion of the circulating light extends outside the resonator, these devices can also be used to probe the surroundings. This interaction has enabled numerous experiments in biology, such as single molecule biodetection and antibody-antigen kinetics, as well as discoveries in other fields, such as development of ultra-low-threshold microlasers, characterization of thin films, and cavity quantum electrodynamics studies.3-7
The two primary silica resonant cavity geometries are the microsphere and the microtoroid. Both devices rely on a carbon dioxide laser reflow step to achieve their ultra-high-Q factors (Q&gt;100 million).1-2,8-9 However, there are several notable differences between the two structures. Silica microspheres are free-standing, supported by a single optical fiber, whereas silica microtoroids can be fabricated on a silicon wafer in large arrays using a combination of lithography and etching steps. These differences influence which device is optimal for a given experiment.
Here, we present detailed fabrication protocols for both types of resonant cavities. While the fabrication of microsphere resonant cavities is fairly straightforward, the fabrication of microtoroid resonant cavities requires additional specialized equipment and facilities (cleanroom). Therefore, this additional requirement may also influence which device is selected for a given experiment.
Introduction
An optical resonator efficiently confines light at specific wavelengths, known as the resonant wavelengths of the device. 1-2 The common figure of merit for these optical resonators is the quality factor or Q. This term describes the photon lifetime (&tau;o) within the resonator, which is directly related to the resonator's optical losses. Therefore, an optical resonator with a high Q factor has low optical losses, long photon lifetimes, and very low photon decay rates (1/&tau;o). As a result of the long photon lifetimes, it is possible to build-up extremely large circulating optical field intensities in these devices. This very unique property has allowed these devices to be used as laser sources and integrated biosensors.10
A unique sub-class of resonators is the whispering gallery mode optical microcavity. In these devices, the light is confined in circular orbits at the periphery. Therefore, the field is not completely confined within the device, but evanesces into the environment. Whispering gallery mode optical cavities have demonstrated some of the highest quality factors of any optical resonant cavity to date.9,11 Therefore, these devices are used throughout science and engineering, including in fundamental physics studies and in telecommunications as well as in biodetection experiments. 3-7,12
Optical microcavities can be fabricated from a wide range of materials and in a wide variety of geometries. A few examples include silica and silicon microtoroids, silicon, silicon nitride, and silica microdisks, micropillars, and silica and polymer microrings.13-17 The range in quality factor (Q) varies as dramatically as the geometry. Although both geometry and high Q are important considerations in any field, in many applications, there is far greater leverage in boosting device performance through Q enhancement. Among the numerous options detailed previously, the silica microsphere and the silica microtoroid resonator have achieved some of the highest Q factors to date.1,9 Additionally, as a result of the extremely low optical loss of silica from the visible through the near-IR, both microspheres and microtoroids are able to maintain their Q factors over a wide range of testing wavelengths.18 Finally, because silica is inherently biocompatible, it is routinely used in biodetection experiments.
In addition to high material absorption, there are several other potential loss mechanisms, including surface roughness, radiation loss, and contamination loss.2 Through an optimization of the device size, it is possible to eliminate radiation losses, which arise from poor optical field confinement within the device. Similarly, by storing a device in an appropriately clean environment, contamination of the surface can be minimized. Therefore, in addition to material loss, surface scattering is the primary loss mechanism of concern.2,8
In silica devices, surface scattering is minimized by using a laser reflow technique, which melts the silica through surface tension induced reflow. While spherical optical resonators have been studied for many years, it is only with recent advances in fabrication technologies that researchers been able to fabricate high quality silica optical toroidal microresonators (Q&gt;100 million) on a silicon substrate, thus paving the way for integration with microfluidics.1
The present series of protocols details how to fabricate both silica microsphere and microtoroid resonant cavities. While silica microsphere resonant cavities are well-established, microtoroid resonant cavities were only recently invented.1 As many of the fundamental methods used to fabricate the microsphere are also used in the more complex microtoroid fabrication procedure, by including both in a single protocol it will enable researchers to more easily trouble-shoot their experiments.

Watch this Scientific Journal Video about Fabrication of Silica Ultra High Quality Factor Microresonators at JoVE.com

Fabrication of Silica Ultra High Quality Factor Microresonators

Biz serbest duran mikroküreler ve on-chip microtoroids dahil silika rezonans kaviteler, imal etmek, bir karbondioksit lazer reflow tekniğinin kullanımı açıklanır. Reflow yöntemi her iki cihaz içinde uzun foton yaşamlar sağlayan, yüzey kusurları kaldırır. Çıkan cihazlar telekomünikasyon gelen biodetection kadar uygulamaları sağlayan, ultra yüksek kalite faktörleri var.

Silika Ultra Yüksek Kalite Faktörü Microresonators Fabrikasyon

Whispering gallery resonant cavities confine light in circular orbits at their periphery.1-2 The photon storage lifetime in the cavity, quantified by the ...

fabrication-of-silica-ultra-high-quality-factor-microresonators

Research

JoVE Journal

Engineering

16.0K Görüntüleme.  University of Southern California. Biz serbest duran mikroküreler ve on-chip microtoroids dahil silika rezonans kaviteler, imal etmek, bir karbondioksit lazer reflow tekniğinin kullanımı açıklanır. Reflow yöntemi her iki cihaz içinde uzun foton yaşamlar sağlayan, yüzey kusurları kaldırır. Çıkan cihazlar telekomünikasyon gelen biodetection kadar uygulamaları sağlayan, ultra yüksek kalite faktörleri var.

Video: Fabrication of Silica Ultra High Quality Factor Microresonators

Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures

The physical properties of a material are defined by its electronic structure. Electrons in solids are characterized by energy (&omega;) and momentum (k) and the probability to find them in a particular state with given &omega; and k is described by the spectral function A(k, &omega;). This function can be directly measured in an experiment based on the well-known photoelectric effect, for the explanation of which Albert Einstein received the Nobel Prize back in 1921. In the photoelectric effect the light shone on a surface ejects electrons from the material. According to Einstein, energy conservation allows one to determine the energy of an electron inside the sample, provided the energy of the light photon and kinetic energy of the outgoing photoelectron are known. Momentum conservation makes it also possible to estimate k relating it to the momentum of the photoelectron by measuring the angle at which the photoelectron left the surface. The modern version of this technique is called Angle-Resolved Photoemission Spectroscopy (ARPES) and exploits both conservation laws in order to determine the electronic structure, i.e. energy and momentum of electrons inside the solid. In order to resolve the details crucial for understanding the topical problems of condensed matter physics, three quantities need to be minimized: uncertainty* in photon energy, uncertainty in kinetic energy of photoelectrons and temperature of the sample.
In our approach we combine three recent achievements in the field of synchrotron radiation, surface science and cryogenics. We use synchrotron radiation with tunable photon energy contributing an uncertainty of the order of 1 meV, an electron energy analyzer which detects the kinetic energies with a precision of the order of 1 meV and a He3 cryostat which allows us to keep the temperature of the sample below 1 K. We discuss the exemplary results obtained on single crystals of Sr2RuO4 and some other materials. The electronic structure of this material can be determined with an unprecedented clarity.

The overall goal of this method is to determine the low-energy electronic structure of solids at ultra-low temperatures using Angle-Resolved Photoemission Spectroscopy with synchrotron radiation.

Ultra-düşük sıcaklıklarda Açı çözüldü Photoemission Spektroskopi

The physical properties of a material are defined by its  electronic structure. Electrons in solids are characterized by energy (&omega;)  and momentum ...

Mühendislik

Synthesis and Microdiffraction at Extreme Pressures and Temperatures

High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary interiors, design materials with novel properties, understand the mechanical behavior of materials exposed to very high stresses as in explosions or impacts. Synthesis and structural analysis of materials at extreme conditions of pressure and temperature entails remarkable technical challenges. In the laser heated diamond anvil cell (LH-DAC), very high pressure is generated between the tips of two opposing diamond anvils forced against each other; focused infrared laser beams, shined through the diamonds, allow to reach very high temperatures on samples absorbing the laser radiation. When the LH-DAC is installed in a synchrotron beamline that provides extremely brilliant x-ray radiation, the structure of materials under extreme conditions can be probed in situ. LH-DAC samples, although very small, can show highly variable grain size, phase and chemical composition. In order to obtain the high resolution structural analysis and the most comprehensive characterization of a sample, we collect diffraction data in 2D grids and combine powder, single crystal and multigrain diffraction techniques. Representative results obtained in the synthesis of a new iron oxide, Fe4O5 1 will be shown.

The laser heated diamond anvil cell combined with synchrotron micro-diffraction techniques allows researchers to explore the nature and properties of new phases of matter at extreme pressure and temperature (PT) conditions. Heterogeneous samples can be characterized in situ under high pressure by 2D mapping and combined powder, single-crystal and multigrain diffraction approaches.

Aşırı basınç ve Sıcaklıklarda sentezi ve mikrodifraksiyon

High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary ...

Convergent Polishing: A Simple, Rapid, Full Aperture Polishing Process of High Quality Optical Flats &amp; Spheres

Convergent Polishing is a novel polishing system and method for finishing flat and spherical glass optics in which a workpiece, independent of its initial shape (i.e., surface figure), will converge to final surface figure with excellent surface quality under a fixed, unchanging set of polishing parameters in a single polishing iteration. In contrast, conventional full aperture polishing methods require multiple, often long, iterative cycles involving polishing, metrology and process changes to achieve the desired surface figure. The Convergent Polishing process is based on the concept of workpiece-lap height mismatch resulting in pressure differential that decreases with removal and results in the workpiece converging to the shape of the lap. The successful implementation of the Convergent Polishing process is a result of the combination of a number of technologies to remove all sources of non-uniform spatial material removal (except for workpiece-lap mismatch) for surface figure convergence and to reduce the number of rogue particles in the system for low scratch densities and low roughness. The Convergent Polishing process has been demonstrated for the fabrication of both flats and spheres of various shapes, sizes, and aspect ratios on various glass materials. The practical impact is that high quality optical components can be fabricated more rapidly, more repeatedly, with less metrology, and with less labor, resulting in lower unit costs. In this study, the Convergent Polishing protocol is specifically described for fabricating 26.5 cm square fused silica flats from a fine ground surface to a polished ~&#955;/2 surface figure after polishing 4 hr per surface on a 81 cm diameter polisher.

A novel optical polishing process, called &#8220;Convergent Polishing&#8221;, which enables faster, lower cost polishing, is described. Unlike conventional polishing processes, Convergent Polishing allows a glass workpiece to be polished in a single iteration and with high surface quality to its final surface figure without requiring changes to polishing parameters.

Yakınsak Polisaj: Yüksek Kaliteli Optik Flats &amp; Kürelerin Basit, Hızlı, Tam Diyafram Parlatma İşlemi

Convergent Polishing is a novel polishing system and method for finishing flat and spherical glass optics in which a workpiece, independent of its initial ...

Fabrication of High Contrast Gratings for the Spectrum Splitting Dispersive Element in a Concentrated Photovoltaic System

High contrast gratings are designed and fabricated and its application is proposed in a parallel spectrum splitting dispersive element that can improve the solar conversion efficiency of a concentrated photovoltaic system. The proposed system will also lower the solar cell cost in the concentrated photovoltaic system by replacing the expensive tandem solar cells with the cost-effective single junction solar cells. The structures and the parameters of high contrast gratings for the dispersive elements were numerically optimized. The large-area fabrication of high contrast gratings was experimentally demonstrated using nanoimprint lithography and dry etching. The quality of grating material and the performance of the fabricated device were both experimentally characterized. By analyzing the measurement results, the possible side effects from the fabrication processes are discussed and several methods that have the potential to improve the fabrication processes are proposed, which can help to increase the optical efficiency of the fabricated devices.

The fabrication of high contrast gratings as the parallel spectrum splitting dispersive element in a concentrated photovoltaic system is demonstrated. Fabrication processes including nanoimprint lithography, TiO2 sputtering and reactive ion etching are described. Reflectance measurement results are used to characterize the optical performance.

Bir Konsantre Fotovoltaik Sistemde Spectrum Yarma Dağılım Eleman Yüksek Kontrast Gratings imalatı

High contrast gratings are designed and fabricated and its application is proposed in a parallel spectrum splitting dispersive element that can improve ...

The Evolution of Silica Nanoparticle-polyester Coatings on Surfaces Exposed to Sunlight

Corrosion of metallic surfaces is prevalent in the environment and is of great concern in many areas, including the military, transport, aviation, building and food industries, amongst others. Polyester and coatings containing both polyester and silica nanoparticles (SiO2NPs) have been widely used to protect steel substrata from corrosion. In this study, we utilized X-ray photoelectron spectroscopy, attenuated total reflection infrared micro-spectroscopy, water contact angle measurements, optical profiling and atomic force microscopy to provide an insight into how exposure to sunlight can cause changes in the micro- and nanoscale integrity of the coatings. No significant change in surface micro-topography was detected using optical profilometry, however, statistically significant nanoscale changes to the surface were detected using atomic force microscopy. Analysis of the X-ray photoelectron spectroscopy and attenuated total reflection infrared micro-spectroscopy data revealed that degradation of the ester groups had occurred through exposure to ultraviolet light to form COO&#903;, -H2C&#903;, -O&#903;, -CO&#903; radicals. During the degradation process, CO and CO2 were also produced.

Two types of surfaces, polyester-coated steel and polyester coated with a layer of silica nanoparticles, were studied. Both surfaces were exposed to sunlight, which was found to cause substantial changes in the chemistry and nanoscale topography of the surface.

Güneş ışığına maruz Yüzeyler Silika Nanoparçacık-polyester kaplamalar Evrimi

Corrosion of metallic surfaces is prevalent in the environment and is of great concern in many areas, including the military, transport, aviation, ...

High Temperature Fabrication of Nanostructured Yttria-Stabilized-Zirconia (YSZ) Scaffolds by In Situ Carbon Templating Xerogels

We demonstrate a method for the high temperature fabrication of porous, nanostructured yttria-stabilized-zirconia (YSZ, 8 mol% yttria - 92 mol% zirconia) scaffolds with tunable specific surface areas up to 80 m2&#183;g-1. An aqueous solution of a zirconium salt, yttrium salt, and glucose is mixed with propylene oxide (PO) to form a gel. The gel is dried under ambient conditions to form a xerogel. The xerogel is pressed into pellets and then sintered in an argon atmosphere. During sintering, a YSZ ceramic phase forms and the organic components decompose, leaving behind amorphous carbon. The carbon formed in situ serves as a hard template, preserving a high surface area YSZ nanomorphology at sintering temperature. The carbon is subsequently removed by oxidation in air at low temperature, resulting in a porous, nanostructured YSZ scaffold. The concentration of the carbon template and the final scaffold surface area can be systematically tuned by varying the glucose concentration in the gel synthesis. The carbon template concentration was quantified using thermogravimetric analysis (TGA), the surface area and pore size distribution was determined by physical adsorption measurements, and the morphology was characterized using scanning electron microscopy (SEM). Phase purity and crystallite size was determined using X-ray diffraction (XRD). This fabrication approach provides a novel, flexible platform for realizing unprecedented scaffold surface areas and nanomorphologies for ceramic-based electrochemical energy conversion applications, e.g. solid oxide fuel cell (SOFC) electrodes.

High Temperature Fabrication of Nanostructured Yttria-Stabilized-Zirconia YSZ Scaffolds by In Situ Carbon Templating Xerogels

A protocol for fabricating porous, nanostructured yttria-stabilized-zirconia (YSZ) scaffolds at temperatures between 1,000 &#176;C and 1,400 &#176;C is presented.

tarafından Nano yapılı yitriya stabilize-Zirkonyum (YSZ) iskelelerinin Yüksek Sıcaklık Fabrikasyon<em&gt; Situ</em&gt; Karbon şablonu Kserojeller

We demonstrate a method for the high temperature fabrication of porous, nanostructured yttria-stabilized-zirconia (YSZ, 8 mol% yttria - 92 mol% zirconia) ...

Scalable Solution-processed Fabrication Strategy for High-performance, Flexible, Transparent Electrodes with Embedded Metal Mesh

Here, the authors report the embedded metal-mesh transparent electrode (EMTE), a new transparent electrode (TE) with a metal mesh completely embedded in a polymer film. This paper also presents a low-cost, vacuum-free fabrication method for this novel TE; the approach combines lithography, electroplating, and imprint transfer (LEIT) processing. The embedded nature of the EMTEs offers many advantages, such as high surface smoothness, which is essential for organic electronic device production; superior mechanical stability during bending; favorable resistance to chemicals and moisture; and strong adhesion with plastic film. LEIT fabrication features an electroplating process for vacuum-free metal deposition and is favorable for industrial mass production. Furthermore, LEIT allows for the fabrication of metal mesh with a high aspect ratio (i.e., thickness to linewidth), significantly enhancing its electrical conductance without adversely losing optical transmittance. We demonstrate several prototypes of flexible EMTEs, with sheet resistances lower than 1 &#937;/sq and transmittances greater than 90%, resulting in very high figures of merit (FoM) &#8211; up to 1.5 x 104 &#8211; which are amongst the best values in the published literature.

This protocol describes a solution-based fabrication strategy for high-performance, flexible, transparent electrodes with fully-embedded, thick metal mesh. Flexible transparent electrodes fabricated by this process demonstrate among the highest reported performances, including ultra-low sheet resistance, high optical transmittance, mechanical stability under bending, strong substrate adhesion, surface smoothness, and environmental stability.

Gömülü Metal Örgülü Yüksek Performanslı, Esnek, Şeffaf Elektrotlar için Ölçeklenebilir Çözeltiyle İşlenmiş Üretim Stratejisi

Here, the authors report the embedded metal-mesh transparent electrode (EMTE), a new transparent electrode (TE) with a metal mesh completely embedded in a ...

Fabrication of Ultra-thin Color Films with Highly Absorbing Media Using Oblique Angle Deposition

Ultra-thin film structures have been studied extensively for use as optical coatings, but performance and fabrication challenges remain.&#160; We present an advanced method for fabricating ultra-thin color films with improved characteristics. The proposed process addresses several fabrication issues, including large area processing. Specifically, the protocol describes a process for fabricating ultra-thin color films using an electron beam evaporator for oblique angle deposition of germanium (Ge) and gold (Au) on silicon (Si) substrates.&#160; Film porosity produced by the oblique angle deposition induces color changes in the ultra-thin film. The degree of color change depends on factors such as deposition angle and film thickness. Fabricated samples of the ultra-thin color films showed improved color tunability and color purity. In addition, the measured reflectance of the fabricated samples was converted into chromatic values and analyzed in terms of color. Our ultra-thin film fabricating method is expected to be used for various ultra-thin film applications such as flexible color electrodes, thin film solar cells, and optical filters. Also, the process developed here for analyzing the color of the fabricated samples is broadly useful for studying various color structures.

We present a detailed method for fabricating ultra-thin color films with improved characteristics for optical coatings. The oblique angle deposition technique using an electron beam evaporator allows improved color tunability and purity. Fabricated films of Ge and Au on Si substrates were analyzed by reflectance measurements and color information conversion.

Eğik açısı ifade kullanarak medya yüksek emici ile Ultra ince renk filmleri imalatı

Ultra-thin film structures have been studied extensively for use as optical coatings, but performance and fabrication challenges remain.&#160; We present ...

Flow-assisted Dielectrophoresis: A Low Cost Method for the Fabrication of High Performance Solution-processable Nanowire Devices

Flow-assisted dielectrophoresis (DEP) is an efficient self-assembly method for the controllable and reproducible positioning, alignment, and selection of nanowires. DEP is used for nanowire analysis, characterization, and for solution-based fabrication of semiconducting devices. The method works by applying an alternating electric field between metallic electrodes. The nanowire formulation is then dropped onto the electrodes which are on an inclined surface to create a flow of the formulation using gravity. The nanowires then align along the gradient of the electric field and in the direction of the liquid flow. The frequency of the field can be adjusted to select nanowires with superior conductivity and lower trap density. 
In this work, flow-assisted DEP is used to create nanowire field effect transistors. Flow-assisted DEP has several advantages: it allows selection of nanowire electrical properties; control of nanowire length; placement of nanowires in specific areas; control of orientation of nanowires; and control of nanowire density in the device. 
The technique can be expanded to many other applications such as gas sensors and microwave switches. The technique is efficient, quick, reproducible, and it uses a minimal amount of dilute solution making it ideal for the testing of novel nanomaterials. Wafer scale assembly of nanowire devices can also be achieved using this technique, allowing large numbers of samples for testing and large-area electronic applications.

In this paper, flow assisted dielectrophoresis is demonstrated for the self-assembly of nanowire devices. The fabrication of a silicon nanowire field effect transistor is shown as an example.

Akış yoluyla Dielectrophoresis: Yüksek performanslı çözüm processable Nanowire cihazları imalatı için düşük maliyetli bir yöntem

Flow-assisted dielectrophoresis (DEP) is an efficient self-assembly method for the controllable and reproducible positioning, alignment, and selection of ...

Determination of Aggregate Surface Morphology at the Interfacial Transition Zone (ITZ)

Here, we present a comprehensive method to illustrate the uneven distribution of the interfacial transition zone (ITZ) around the aggregate and the effect of aggregate surface morphology on the formation of ITZ. First, a model concrete sample is prepared with a spherical ceramic particle in roughly the central part of the cement matrix, acting as a coarse aggregate used in common concrete/mortar. After curing until the designed age, the sample is scanned by X-ray computed tomography to determine the relative location of the ceramic particle inside the cement matrix. Three locations of the ITZ are chosen: above the aggregate, on the side of the aggregate, and below the aggregate. After a series of treatments, the samples are scanned with a SEM-BSE detector. The resultant images were further processed using a digital image processing method (DIP) to obtain quantitative characteristics of the ITZ. The surface morphology is characterized at the pixel level based on the digital image. Thereafter, K-means clustering method is used to illustrate the effect of surface roughness on ITZ formation.

Determination of Aggregate Surface Morphology at the Interfacial Transition Zone ITZ

Hereby, we proposed a protocol to illustrate the effect of aggregate surface morphology on the ITZ microstructure. The SEM-BSE image were quantitatively analyzed to obtain ITZ's porosity gradient via digital image processing and a K-means clustering algorithm was further employed to establish a relationship between porosity gradient and surface roughness.

İnterasiyal Geçiş Bölgesinde (ITZ) Agrega Yüzey Morfolojisinin Belirlenmesi

Here, we present a comprehensive method to illustrate the uneven distribution of the interfacial transition zone (ITZ) around the aggregate and the effect ...