作者は感謝して国立科学財団（：CMMI-0653578、CBET-0853890グラントはありません）することにより、この研究のために財政支援を承諾したがっています。

1。光学システムのセットアップ（図1） <ol><li>半波長板とレーザーパルスのエネルギーを調整するためにレーザ出力を次の偏光板を設定します。 </li><li>ポンプパルスとプローブパルス：2パルスにレーザーパルスを分割するために偏光した後にビームスプリッタを設定します。 </li><li>ポンプパルスを光遅延デバイスを構築するために4つの反射鏡と手動並進ステージを使用しています。 </li><li>垂直にターゲット表面に到達するためのポンプパルスを導くために別の4の反射鏡を使用しています。 </li><li> 800乃至400nmのレーザーパルスの波長を変換する第2高調波発生（SHG）を設定します。 </li><li> 800 nmのパルスを送信し、400 nmのパルスを反映するために高調波セパレーターを使用しています。 </li><li>ビーム減速とプローブパルスの大きさと収束を調整する限局レンズのペアを設定します。 </li><li>ステップ1.3で述べたように、プローブパルスのために、別の光遅延装置を設定します。 </li><li>の面積を調整するアイリスリングを使用プローブパルスとプローブパルスが水平にターゲット表面を通過して、ポンプパルスと交差していることを確認します。 </li><li>激化電荷結合素子（ICCD）カメラで受信されるプラズマ領域の画像を生成する2つの対物レンズと、複数のフィルタを設定します。 </li><li>コンピュータ、レーザー、ICCDカメラとBNCケーブルまたはUSBケーブルを使用して、そのコントローラを接続します。 </li><li>プローブパルスのイメージをキャプチャカメラまで、カメラコントローラの遅延時間を調整します。したがって、プローブパルスとカメラが同期されます。 </li></ol> 2。ポンプ·プローブの同期<ol><li>ポンプパルスとプローブパルスの交差点にビームスプリッタを配置し、これら二つのパルスを受信する2つのフォトダイオードを設定します。これら二つのフォトダイオードは、離れてビームスプリッタから同じ距離を持つ必要があります。 </li><li>これら二つのフォトダイオードの信号を受信するようにオシロスコープを使用して、プロまで、ポンプパルスビーム経路上に遅延ステージを移動しますポンプパルスとプローブパルスのファイルは、オシロスコープの画面上で互いに重複しています。 20 psの精度は、オシロスコープの時間分解能のおかげで実現しています。 </li><li>ステップ2.1で述べたように、ビームスプリッタと2つのフォトダイオードを削除します。 </li><li>空気破壊領域がちょうどICCD画面上に観察されたまでのポンプパルスビーム経路上に遅延ステージを調整します。空気の絶縁破壊の形成が一様な背景の代わりに検出することができた時間は、遅延時間ゼロとして決定されます。 </li></ol> 3。サンプルステージの準備<ol><li> 3つの自由度でサンプルを移動するためにラボジャッキと2手動リニアステージを設定します。 </li><li>ステージの高平坦度を達成するためにダイヤルインジケータと高精度シムを使用しています。高さの差は25.4ミリメートルの距離あたり1μm以内である必要があります。 </li><li>フライス盤を使用して、0.8ミリメートルの厚さのCuシートのうち、正方形のピース（30ミリメートル×30ミリメートル）の削減マシン。 </li><li>表面粗さが0.5μmの下になるまでのCu片の狭い側面（30ミリメートル×0.8ミリメートル）を磨く。 </li><li>洗練された狭い表向きでトップの手動ステージ上の銅の部分を修正します。 </li><li>ステップ3.1で述べたように、任意の傾きが対象の下に高精度シムを挿入することによって調整することができるようなICCDカメラを介してその位置を監視しながら）1つのマニュアルステージでターゲットを移動します。 </li><li>他のマニュアルステージで、ステップ3.6を繰り返します。 </li><li>第三高精度の手動ステージで焦点レンズの位置を変更しながら、ターゲット上の穴のダースを開けます。焦点の位置は、最小の穴があけられ焦点レンズの位置に対応しています。 </li></ol> 4。アブレーションと測定<ol><li>離れて焦点から約50μmまでの距離を焦点距離のレンズを上に移動します。 </li><li> 10 psのそれまでの2つのPSイメージをキャプチャするために0.3mmの間隔でプローブパルスビーム経路上に遅延ステージを移動したり、480 PSまで画像毎に20 psのをキャプチャするために3mmの間隔で。 </li><li>再現性と精度のために数回のステップ4.2を繰り返します。 </li><li>離れて焦点から約50μmの距離に焦点レンズを下に移動し、ステップ4.3を繰り返します。 </li></ol> 5。代表的な結果測定した影絵の画像は図に示されています。 2および図。それぞれわずかにターゲット表面上に、以下のフォーカルポイントの3、。縦方向および半径方向の膨張の位置を図にプロットされます。 4、図。 5。最初の100 psのこれらの2つのケースの長手方向の展開は大幅に異なっているが、次は400 psとその半径方向の拡張でその長手方向の展開は似ています。最初のケースでは、100 ps以内の初期プラズマは、複数の層から成る一次元拡張構造を持っています。後者の場合、初期のPLのためにASMAは、100 ps以内あまり変わりません、二次元展開構造を有している。 シミュレーションモデル12は、初期のプラズマの進化のメカニズムを調べるために使用されます。時間ゼロは、レーザーパルスのピークがターゲット表面に到達する時間として定義されます。 図に示すようにシミュレートされた初期のプラズマの進化プロセスは、これら2例の両方の測定結果とよく一致する。 6および図。それぞれ7、。 1 ps以内の初期プラズマの形成はまた、最初のケースのシミュレーションモデルを用いて、 図に示すように予測されています。 8。初期のプラズマは空気破壊領域とCuのプラズマ領域を持っていることが判明した。空気の内訳は、最初の多光子イオン化によって引き起こされ、その後、アバランシェイオン化が続いている。二番目のケースは、しかし、焦点は、以下のターゲット表面であり、個別の空気の破壊領域が形成されていません。代わりに、空気イオンは、Cu PLAの近くに発生します。SMA（前面パネル）とCuターゲットから放出され、自由電子に衝突電離によりによって引き起こされます。 <img alt="図1" src="/files/ftp_upload/4033/4033fig1.jpg" /> 図1ポンプ·プローブ影絵測定の模式図。 <img alt="図2" src="/files/ftp_upload/4033/4033fig2.jpg" /> 図2。少し表面上の焦点を持つ連続した遅延時間でのCuのプラズマ拡大。レーザー波長：800 nmで、パルス幅：100 fsは、電力密度：4.2×10 14 W / cm 2で 、ターゲット：銅。 <img alt="図3" src="/files/ftp_upload/4033/4033fig3.jpg" /> 図3。少し表面の下に焦点を持つ連続した遅延時間でのCuのプラズマ拡大。レーザー波長：800 nmで、パルス幅：100 fsは、電力密度：4.2×10 14 W / cm 2で 、ターゲット：銅。 &lt;IMG ALT = &quot;図4&quot; SRC = &quot;/ files/ftp_upload/4033/4033fig4.jpg&quot; /&gt; 図4プラズマの縦とわずかに表面上に焦点を持つ連続した遅延時間での径方向の膨張位置。レーザー波長：800 nmで、パルス幅：100 fsは、電力密度：4.2×10 14 W / cm 2で 、ターゲット：銅。 <img alt="図5" src="/files/ftp_upload/4033/4033fig5.jpg" /> 図5。わずかに表面の下に焦点を持つ連続した遅延時間でのプラズマ、縦方向および半径方向の膨張位置。レーザー波長：800 nmで、パルス幅：100 fsは、電力密度：4.2×10 14 W / cm 2で 、ターゲット：銅。 図6。少し表面上の焦点と70 psの遅延時間内に測定値と計算値のプラズマ膨張のアニメーション。レーザー波長：800 nmで、パルス幅：100 fsは、電力密度：4.2×10 14 </suP&gt; W / cm 2で 、ターゲット：Cuは、 <a href="http://www.jove.com/files/ftp_upload/4033/4033movie6.avi" target="_blank">アニメーションを表示するには、ここをクリックしてください</a> 。 図7。少し表面下焦点と70 psの遅延時間内に測定値と計算値のプラズマ膨張のアニメーション。レーザー波長：800 nmで、パルス幅：100 fsは、電力密度：4.2×10 14 W / cm 2で 、ターゲット：銅。 <a href="http://www.jove.com/files/ftp_upload/4033/4033movie7.avi" target="_blank">アニメーションを表示するには、ここをクリックしてください</a> 。 図8。少し表面上の焦点と1ピコ秒の遅延時間内に測定値と計算値のプラズマ膨張のアニメーション。レーザー波長：800 nmで、パルス幅：100 fsは、電力密度：4.2×10 14 W / cm 2で 、ターゲット：Cuの<a href="http://www.jove.com/files/ftp_upload/4033/4033movie8.avi" target="_blank">アニメーションを表示するには、ここをクリック&lt;</a>/&gt;。

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利害の衝突が宣言されません。

本論文で提示さ測定とシミュレーションの方法は、初期のプラズマのダイナミクスと空気とCuの両方のイオン化のメカニズムの理解をより正確に検査を有効にしてください。高品質のプラズマの構造は、1 psと1μmの空間分解能の時間分解能で撮影されています。この測定は、高すぎると再現性を持っています。重要な手順は非常によくビームを調整し、高い平坦度などの低粗さをターゲット表面を準備することです。 このアプローチは、他のターゲット材料と様々なレーザパラメータに適用することができます。ポンプ·プローブ影絵法の唯一の制限は、低すぎると電子数密度の変化である。

<table border="1"><tbody><tr><td> 機器の名前 </td><td> 会社 </td><td> カタログ番号 </td></tr><tr><td>レーザー</td><td>スペクトラ·フィジックス</td><td> SPTF-100F-1K-1P </td></tr><tr><td> ICCDカメラ</td><td>プリンストンインスツルメンツ</td><td> 7467-0028 </td></tr><tr><td>オシロスコープ</td><td> Rigol </td><td> DS1302CA </td></tr><tr><td>フォトダイオード</td><td>ニューポート</td><td> 818-BB30 </td></tr><tr><td>リニアステージ</td><td>ニューポート</td><td> 433 </td></tr><tr><td>インジケータをダイヤル</td><td>ミツトヨ</td><td> ID-C112E </td></tr></tbody></table>

investigation of early plasma evolution induced by ultrashort laser pulses

初期のプラズマは、ターゲットの高強度レーザー照射とその後のターゲット材料のイオン化により生成されます。そのダイナミクスは、特に空気環境1-11に、レーザー物質相互作用に重要な役割を果たしている。 初期のプラズマの進化は、ポンプ·プローブshadowgraphy 1-3と干渉1,4-7を介してキャプチャされています。しかし、時間枠を学び、適用されたレーザーパラメータの範囲は限られています。たとえば、レーザーパルスのピークに関しては100ピコ秒の遅延時間（PS）内のプラズマの前面の位置と電子数密度の直接検査では特に100フェムト秒（fs）の前後期間の短パルスでは、まだ非常に少なく、 10 14 W / cm 2の程度の低電力密度。これらの条件下で生成された初期のプラズマは、高時間空間分解能12で最近捕獲された。詳細なセットアップの戦略とこの高精度測定の手順は、このホワイト·ペーパーで説明する。測定の原理は、光ポンプ·プローブshadowgraphy次のとおりです。それらの間の遅延時間は、その光路長を変えることによって調整することができますが1超短レーザーパルスは、ポンプパルスとプローブパルスに分割されています。ポンプパルスは、ターゲットをablates、初期プラズマを生成し、プローブパルスは、プラズマ領域を介して伝播し、電子数密度の不均一性を検出します。さらに、アニメーションは、文献のシミュレーションモデルから計算結果を使用して生成されます12は非常に高い分解能（0.04〜1ピコ秒）を持つプラズマの形成と進化を説明するために。 実験方法およびシミュレーションの両方のメソッドは、タイムフレームとレーザーのパラメータの広い範囲に適用することができます。これらのメソッドは、金属からだけでなく、半導体や絶縁体からだけでなく、生成された初期のプラズマを調べるために使用することができます。

Watch this Scientific Journal Video about Investigation of Early Plasma Evolution Induced by Ultrashort Laser Pulses at JoVE.com

Investigation of Early Plasma Evolution Induced by Ultrashort Laser Pulses

超短レーザーパルスによって誘導される初期のプラズマの進化を調べるための実験方法が記載されている。この方法を使用して、初期のプラズマの高品質の画像は、高時間·空間分解能が得られる。小説統合された原子モデルは、初期のプラズマのメカニズムをシミュレートし、説明するために使用されています。

超短レーザーパルスにより誘起された初期プラズマの進化の解明

Early plasma is generated owing to high intensity laser irradiation of target and the subsequent target material ionization. Its dynamics plays a ...

investigation-early-plasma-evolution-induced-ultrashort-laser

Research

JoVE Journal

Engineering

14.8K ビュー.  Purdue University. 超短レーザーパルスによって誘導される初期のプラズマの進化を調べるための実験方法が記載されている。この方法を使用して、初期のプラズマの高品質の画像は、高時間·空間分解能が得られる。小説統合された原子モデルは、初期のプラズマのメカニズムをシミュレートし、説明するために使用されています。

ビデオ: Investigation of Early Plasma Evolution Induced by Ultrashort Laser Pulses

Fabrication of Nano-engineered Transparent Conducting Oxides by Pulsed Laser Deposition

Nanosecond Pulsed Laser Deposition (PLD) in the presence of a background gas allows the deposition of metal oxides with tunable morphology, structure, density and stoichiometry by a proper control of the plasma plume expansion dynamics. Such versatility can be exploited to produce nanostructured films from compact and dense to nanoporous characterized by a hierarchical assembly of nano-sized clusters. In particular we describe the detailed methodology to fabricate two types of Al-doped ZnO (AZO) films as transparent electrodes in photovoltaic devices: 1) at low O2 pressure, compact films with electrical conductivity and optical transparency close to the state of the art transparent conducting oxides (TCO) can be deposited at room temperature, to be compatible with thermally sensitive materials such as polymers used in organic photovoltaics (OPVs); 2) highly light scattering hierarchical structures resembling a forest of nano-trees are produced at higher pressures. Such structures show high Haze factor (&gt;80%) and may be exploited to enhance the light trapping capability. The method here described for AZO films can be applied to other metal oxides relevant for technological applications such as TiO2, Al2O3, WO3 and Ag4O4.

We describe the experimental method to deposit nanostructured oxide thin films by nanosecond Pulsed Laser Deposition (PLD) in the presence of a background gas. By using this method Al-doped ZnO (AZO) films, from compact to hierarchically structured as nano-tree forests, can be deposited.

パルスレーザー蒸着法によるナノエンジニアリング透明導電性酸化物の作製

Nanosecond Pulsed  Laser Deposition (PLD) in the presence of a background gas allows the deposition  of metal oxides with tunable morphology, structure, ...

工学

Laser-induced Breakdown Spectroscopy: A New Approach for Nanoparticle's Mapping and Quantification in Organ Tissue

Emission spectroscopy of laser-induced plasma was applied to elemental analysis of biological samples. Laser-induced breakdown spectroscopy (LIBS) performed on thin sections of rodent tissues: kidneys and tumor, allows the detection of inorganic elements such as (i) Na, Ca, Cu, Mg, P, and Fe, naturally present in the body and (ii) Si and Gd, detected after the injection of gadolinium-based nanoparticles. The animals were euthanized 1&#160;to 24 hr&#160;after intravenous injection of particles. A two-dimensional scan of the sample, performed using a motorized micrometric 3D-stage, allowed the infrared laser beam exploring the surface with a lateral resolution less than 100 &#956;m. Quantitative chemical images of Gd element inside the organ were obtained with sub-mM sensitivity. LIBS offers a simple and robust method to study the distribution of inorganic materials without any specific labeling. Moreover, the compatibility of the setup with standard optical microscopy emphasizes its potential to provide multiple images of the same biological tissue with different types of response:&#160;elemental, molecular, or cellular.

Laser-induced Breakdown Spectroscopy: A New Approach for Nanoparticle&#039;s Mapping and Quantification in Organ Tissue

Laser-induced breakdown spectroscopy performed on thin organ and tumor tissue successfully detected natural elements and artificially injected gadolinium (Gd), issued from Gd-based nanoparticles. Images of chemical elements reached a resolution of 100 &#956;m and quantitative sub-mM sensitivity. The compatibility of the setup with standard optical microscopy emphasizes its potential to provide multiple images of a same biological tissue.

レーザー誘起ブレークダウン分光法：臓器組織内のナノ粒子のマッピングと定量化のための新たなアプローチ

Emission spectroscopy of laser-induced plasma was applied to elemental analysis of biological samples. Laser-induced breakdown spectroscopy (LIBS) ...

Laser-induced Forward Transfer for Flip-chip Packaging of Single Dies

Flip-chip (FC) packaging is a key technology for realizing high performance, ultra-miniaturized and high-density circuits in the micro-electronics industry. In this technique the chip and/or the substrate is bumped and the two are bonded via these conductive bumps. Many bumping techniques have been developed and intensively investigated since the introduction of the FC technology in 19601 such as stencil printing, stud bumping, evaporation and electroless/electroplating2. Despite the progress that these methods have made they all suffer from one or more than one drawbacks that need to be addressed such as cost, complex processing steps, high processing temperatures, manufacturing time and most importantly the lack of flexibility. In this paper, we demonstrate a simple and cost-effective laser-based bump forming technique known as Laser-induced Forward Transfer (LIFT)3. Using the LIFT technique a wide range of bump materials can be printed in a single-step with great flexibility, high speed and accuracy at RT. In addition, LIFT enables the bumping and bonding down to chip-scale, which is critical for fabricating ultra-miniature circuitry.

We demonstrate the use of the Laser-induced Forward Transfer (LIFT) technique for flip-chip assembly of optoelectronic components. This approach provides a simple, cost-effective, low-temperature, fast and flexible solution for fine-pitch bumping and bonding on chip-scale for achieving high-density circuits for optoelectronic applications.

シングルダイのフリップチップ実装用のレーザー誘起フォワード転送

Flip-chip (FC) packaging is a key technology for realizing high performance, ultra-miniaturized and high-density circuits in the micro-electronics ...

Selective Area Modification of Silicon Surface Wettability by Pulsed UV Laser Irradiation in Liquid Environment

The wettability of silicon (Si) is one of the important parameters in the technology of surface functionalization of this material and fabrication of biosensing devices. We report on a protocol of using KrF and ArF lasers irradiating Si (001) samples immersed in a liquid environment with low number of pulses and operating at moderately low pulse fluences to induce Si wettability modification. Wafers immersed for up to 4 hr in a 0.01% H2O2/H2O solution did not show measurable change in their initial contact angle (CA) ~75&#176;. However, the 500-pulse KrF and ArF lasers irradiation of such wafers in a microchamber filled with 0.01% H2O2/H2O solution at 250 and 65 mJ/cm2, respectively, has decreased the CA to near 15&#176;, indicating the formation of a superhydrophilic surface. The formation of OH-terminated Si (001), with no measurable change of the wafer&#8217;s surface morphology, has been confirmed by X-ray photoelectron spectroscopy and atomic force microscopy measurements. The selective area irradiated samples were then immersed in a biotin-conjugated fluorescein-stained nanospheres solution for 2 hr, resulting in a successful immobilization of the nanospheres in the non-irradiated area. This illustrates the potential of&#160;the method for selective area biofunctionalization and fabrication of advanced Si-based biosensing architectures. We also describe a similar protocol of irradiation of wafers immersed in methanol (CH3OH) using ArF laser operating at pulse fluence of 65 mJ/cm2 and in situ formation of a strongly hydrophobic surface of Si (001) with the CA of 103&#176;. The XPS results indicate ArF laser induced formation of Si&#8211;(OCH3)x compounds responsible for the observed hydrophobicity. However, no such compounds were found by XPS on the Si surface irradiated by KrF laser in methanol, demonstrating the inability of the KrF laser to photodissociate methanol and create -OCH3 radicals.

We report on a process of in situ alteration of HF treated Si (001) surface into a hydrophilic or hydrophobic state by irradiating samples in microfluidic chambers filled with&#160;H2O2/H2O solution (0.01%-0.5%) or methanol solutions using pulsed UV laser of a relative low pulse fluence.

液体環境におけるパルスUVレーザー照射によるシリコン表面の濡れ性の選択エリア変更

The wettability of silicon (Si) is one of the important parameters in the technology of surface functionalization of this material and fabrication of ...

How to Ignite an Atmospheric Pressure Microwave Plasma Torch without Any Additional Igniters

This movie shows how an atmospheric pressure plasma torch can be ignited by microwave power with no additional igniters. After ignition of the plasma, a stable and continuous operation of the plasma is possible and the plasma torch can be used for many different applications. On one hand, the hot (3,600 K gas temperature) plasma can be used for chemical processes and on the other hand the cold afterglow (temperatures down to almost RT) can be applied for surface processes. For example chemical syntheses are interesting volume processes. Here the microwave plasma torch can be used for the decomposition of waste gases which are harmful and contribute to the global warming but are needed as etching gases in growing industry sectors like the semiconductor branch. Another application is the dissociation of CO2. Surplus electrical energy from renewable energy sources can be used to dissociate CO2 to CO and O2. The CO can be further processed to gaseous or liquid higher hydrocarbons thereby providing chemical storage of the energy, synthetic fuels or platform chemicals for the chemical industry. Applications of the afterglow of the plasma torch are the treatment of surfaces to increase the adhesion of lacquer, glue or paint, and the sterilization or decontamination of different kind of surfaces. The movie will explain how to ignite the plasma solely by microwave power without any additional igniters, e.g., electric sparks. The microwave plasma torch is based on a combination of two resonators &#8212; a coaxial one which provides the ignition of the plasma and a cylindrical one which guarantees a continuous and stable operation of the plasma after ignition. The plasma can be operated in a long microwave transparent tube for volume processes or shaped by orifices for surface treatment purposes.

This movie shows how an atmospheric plasma torch can be ignited by microwaves with no additional igniters and provides a stable and continuous plasma operation suitable for plenty of applications.

追加のイグナイタずに大気圧マイクロ波プラズマトーチに点火する方法

This movie shows how an atmospheric pressure plasma torch can be ignited by microwave power with no additional igniters. After ignition of the plasma, a ...

Automation of Mode Locking in a Nonlinear Polarization Rotation Fiber Laser through Output Polarization Measurements

When a laser is mode-locked, it emits a train of ultra-short pulses at a repetition rate determined by the laser cavity length. This article outlines a new and inexpensive procedure to force mode locking in a pre-adjusted nonlinear polarization rotation fiber laser. This procedure is based on the detection of a sudden change in the output polarization state when mode locking occurs. This change is used to command the alignment of the intra-cavity polarization controller in order to find mode-locking conditions. More specifically, the value of the first Stokes parameter varies when the angle of the polarization controller is swept and, moreover, it undergoes an abrupt variation when the laser enters the mode-locked state. Monitoring this abrupt variation provides a practical easy-to-detect signal that can be used to command the alignment of the polarization controller and drive the laser towards mode locking. This monitoring is achieved by feeding a small portion of the signal to a polarization analyzer measuring the first Stokes parameter. A sudden change in the read out of this parameter from the analyzer will occur when the laser enters the mode-locked state. At this moment, the required angle of the polarization controller is kept fixed. The alignment is completed. This procedure provides an alternate way to existing automating procedures that use equipment such as an optical spectrum analyzer, an RF spectrum analyzer, a photodiode connected to an electronic pulse-counter or a nonlinear detecting scheme based on two-photon absorption or second harmonic generation. It is suitable for lasers mode locked by nonlinear polarization rotation. It is relatively easy to implement, it requires inexpensive means, especially at a wavelength of 1550 nm, and it lowers the production and operation costs incurred in comparison to the above-mentioned techniques.

A protocol to detect and automate mode locking in a pre-adjusted nonlinear polarization rotation fiber laser is presented. The detection of a sudden change in the output polarization state when mode locking occurs is used to command the alignment of an intra-cavity polarization controller in order to find mode-locking conditions.

出力偏光測定を通じて非線形偏波回転ファイバレーザにおけるモードロックの自動化

When a laser is mode-locked, it emits a train of ultra-short pulses at a repetition rate determined by the laser cavity length. This article outlines a ...

Laser-induced Forward Transfer of Ag Nanopaste

Over the past decade, there has been much development of non-lithographic methods1-3 for printing metallic inks or other functional materials. Many of these processes such as inkjet3 and laser-induced forward transfer (LIFT)4 have become increasingly popular as interest in printable electronics and maskless patterning has grown. These additive manufacturing processes are inexpensive, environmentally friendly, and well suited for rapid prototyping, when compared to more traditional semiconductor processing techniques. While most direct-write processes are confined to two-dimensional structures and cannot handle materials with high viscosity (particularly inkjet), LIFT can transcend both constraints if performed properly. Congruent transfer of three dimensional pixels (called voxels), also referred to as laser decal transfer (LDT)5-9, has recently been demonstrated with the LIFT technique using highly viscous Ag nanopastes to fabricate freestanding interconnects, complex voxel shapes, and high-aspect-ratio structures. In this paper, we demonstrate a simple yet versatile process for fabricating a variety of micro- and macroscale Ag structures. Structures include simple shapes for patterning electrical contacts, bridging and cantilever structures, high-aspect-ratio structures, and single-shot, large area transfers using a commercial digital micromirror device (DMD) chip.

We demonstrate the use of the Laser-induced forward transfer technique (LIFT) for the printing of high-viscosity Ag paste. This technique offers a simple, low temperature, robust process for non-lithographically printing microscale 2D and 3D structures.

銀ナノペーストのレーザー誘起フォワード転送

Over the past decade, there has been much development of non-lithographic methods1-3 for printing metallic inks or other functional materials. Many of ...

An Atmospheric Pressure Plasma Setup to Investigate the Reactive Species Formation

Non-thermal atmospheric pressure (&#39;cold&#39;) plasmas have received increased attention in recent years due to their significant biomedical potential. The reactions of cold plasma with the surrounding atmosphere yield a variety of reactive species, which can define its effectiveness. While efficient development of cold plasma therapy requires kinetic models, model benchmarking needs empirical data. Experimental studies of the source of reactive species detected in aqueous solutions exposed to plasma are still scarce. Biomedical plasma is often operated with He or Ar feed gas, and a specific interest lies in investigation of the reactive species generated by plasma with various gas admixtures (O2, N2, air, H2O vapor, etc.) Such investigations are very complex due to difficulties in controlling the ambient atmosphere in contact with the plasma effluent. In this work, we addressed common issues of &#39;high&#39; voltage kHz frequency driven plasma jet experimental studies. A reactor was developed allowing the exclusion of ambient atmosphere from the plasma-liquid system. The system thus comprised the feed gas with admixtures and the components of the liquid sample. This controlled atmosphere allowed the investigation of the source of the reactive oxygen species induced in aqueous solutions by He-water vapor plasma. The use of isotopically labelled water allowed distinguishing between the species originating in the gas phase and those formed in the liquid. The plasma equipment was contained inside a Faraday cage to eliminate possible influence of any external field. The setup is versatile and can aid in further understanding the cold plasma-liquid interactions chemistry.

An experimental setup was created for the helium-operated kHz frequency plasma jet. The setup includes a cage for the plasma power supply and jet and an in-house built reactor to monitor plasma-induced reactive species without the interference of the ambient atmosphere.

反応種の形成を調査するための大気圧プラズマのセットアップ

Non-thermal atmospheric pressure (&#39;cold&#39;) plasmas have received increased attention in recent years due to their significant biomedical potential. ...

Fabrication of 1-D Photonic Crystal Cavity on a Nanofiber Using Femtosecond Laser-induced Ablation

We present a protocol for fabricating 1-D Photonic Crystal (PhC) cavities on subwavelength-diameter tapered optical fibers, optical nanofibers, using femtosecond laser-induced ablation. We show that thousands of periodic nano-craters are fabricated on an optical nanofiber by irradiating with just a single femtosecond laser pulse. For a typical sample, periodic nano-craters with a period of 350 nm and with diameter gradually varying from 50 - 250 nm over a length of 1 mm are fabricated on a nanofiber with diameter around 450 - 550 nm. A key aspect of such a nanofabrication is that the nanofiber itself acts as a cylindrical lens and focuses the femtosecond laser beam on its shadow surface. Moreover, the single-shot fabrication makes it immune to mechanical instabilities and other fabrication imperfections. Such periodic nano-craters on nanofiber, act as a 1-D PhC and enable strong and broadband reflection while maintaining the high transmission out of the stopband. We also present a method to control the profile of the nano-crater array to fabricate apodized and defect-induced PhC cavities on the nanofiber. The strong confinement of the field, both transverse and longitudinal, in the nanofiber-based PhC cavities and the efficient integration to the fiber networks, may open new possibilities for nanophotonic applications and quantum information science.

We present a protocol for fabricating 1-D photonic crystal cavities on subwavelength diameter silica fibers (optical nanofibers) using femtosecond laser-induced ablation.

フェムト秒レーザー誘起アブレーションを用いたナノファイバー上の1次元フォトニック結晶共振器の作製

We present a protocol for fabricating 1-D Photonic Crystal (PhC) cavities on subwavelength-diameter tapered optical fibers, optical nanofibers, using ...

Subsurface Defect Localization by Structured Heating Using Laser Projected Photothermal Thermography

The presented method is used to locate subsurface defects oriented perpendicularly to the surface. To achieve this, we create destructively interfering thermal wave fields that are disturbed by the defect. This effect is measured and used to locate the defect. We form the destructively interfering wave fields by using a modified projector. The original light engine of the projector is replaced with a fiber-coupled high-power diode laser. Its beam is shaped and aligned to the projector&#39;s spatial light modulator and optimized for optimal optical throughput and homogeneous projection by first characterizing the beam profile, and, second, correcting it mechanically and numerically. A high-performance infrared (IR) camera is set up according to the tight geometrical situation (including corrections of the geometrical image distortions) and the requirement to detect weak temperature oscillations at the sample surface. Data acquisition can be performed once a synchronization between the individual thermal wave field sources, the scanning stage, and the IR camera is established by using a dedicated experimental setup which needs to be tuned to the specific material being investigated. During data post-processing, the relevant information on the presence of a defect below the surface of the sample is extracted. It is retrieved from the oscillating part of the acquired thermal radiation coming from the so-called depletion line of the sample surface. The exact location of the defect is deduced from the analysis of the spatial-temporal shape of these oscillations in a final step. The method is reference-free and very sensitive to changes within the thermal wave field. So far, the method has been tested with steel samples but is applicable to different materials as well, in particular to temperature sensitive materials.

This method aims at locating vertical subsurface defects. Here, we couple a laser with a spatial light modulator and trigger its video input to heat a sample surface deterministically with two anti-phased modulated lines while acquiring highly resolved thermal images. The defect position is retrieved from evaluating thermal wave interference minima.

レーザー光熱サーモグラフィーを用いた構造化加熱による地中欠陥局在

The presented method is used to locate subsurface defects oriented perpendicularly to the surface. To achieve this, we create destructively interfering ...