Name: high-speed optical diagnostics of a supersonic ping-pong cannon
Uploaded: 2023-03-24T13:10:00
Description: Watch this Scientific Journal Video about High-Speed Optical Diagnostics of a Supersonic Ping-Pong Cannon at JoVE.com

この作業は、IUSE:EHRプログラムの一環として、NSF学部教育部門(賞#2021157)によってサポートされています。

1.卓球砲(PPC)の構築と組み立て
<ol><li>図1に従ってPPCのすべてのコンポーネントを組み立てます。</li>
	<li>大砲の側面に2つの透明度の高いアクリル窓を挿入して、大砲の内部を光学的にプローブできるようにします。<ol><li>大砲の出口近くのPVCの反対側に2つの1/2穴を開けます。</li>
		<li>レーザー彫刻機を使用して、厚いアクリル窓に2つの1/8を準備します。3 ?...

<ol>
	<li>Peterson, R. W., Pulford, B. N., Stein, K. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+ping-pong+cannon:+A+closer+look.">The ping-pong cannon: A closer look.</a> The Physics Teacher. 43 (1), 22-25 (2005).</li><li>Olson, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+shock+waves+in+expansion+tube+accelerators.">The role of shock waves in expansion tube accelerators.</a> American Journal of Physics. 74 (12), 1071-1076 (2006).</li><li>Cockman, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improved+vacuum+bazooka.">Improved vacuum bazooka.</a> The Physics Teacher. 41 (4), 246-247 (2003).</li><li>Ayars, E., Buchholtz, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+the+vacuum+cannon.">Analysis of the vacuum cannon.</a> American Journal of Physics. 72 (7), 961-963 (2004).</li><li>Thuecks, D. J., Demas, H. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+the+effect+of+air-intake+aperture+size+in+the+ping-pong+ball+cannon.">Modeling the effect of air-intake aperture size in the ping-pong ball cannon.</a> American Journal of Physics. 87 (2), 136-140 (2019).</li><li>Liepmann, H. W., Roshko, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Elements of gas dynamics. , (1957).</li><li>Settles, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Schlieren and shadowgraph techniques. , (2001).</li><li>Geisert, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+single+mirror+schlieren+optical+system.">A single mirror schlieren optical system.</a> American Journal of Physics. 52 (5), 467 (1984).</li><li>French, R. M., Gorrepati, V., Alcorta, E., Jackson, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+mechanics+of+a+ping-pong+ball+gun.">The mechanics of a ping-pong ball gun.</a> Experimental Techniques. 32 (1), 24-30 (2008).</li><li>French, M., Zehrung, C., Stratton, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+supersonic+ping-pong+gun.">A supersonic ping-pong gun.</a> arXiv. , (2013).</li><li>French, F., Choudhuri, R., Stratton, J., Zehrung, C., Huston, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+modular+supersonic+ping-pong+gun.">A modular supersonic ping-pong gun.</a> arXiv. , (2018).</li><li>Fredrick, C. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Complementary+studies+on+supersonic+nozzle+flow:+heterodyne+interferometry,+high-speed+video+shadowgraphy,+and+numerical+simulation.">Complementary studies on supersonic nozzle flow: heterodyne interferometry, high-speed video shadowgraphy, and numerical simulation.</a> WIT Transactions on Modelling and Simulation. 59, 223-234 (2015).</li></ol>

我々は、ボール速度の測定と大砲の出口付近の衝撃伝播の特性評価のための光学診断とともに、PPCとSSPPCを構築するための方法を提示しました。標準PPCは、スケジュール2の1.5PVCパイプの80mセクションで構成されています。パイプには、両端にフランジ、クイックコネクト真空継手、レーザー診断用の出口近くのアクリル窓が取り付けられています。PPCの詳細な回路図を 図1</str...

PPCは、人々が絶えずさらされる巨大な空気圧を示すために使用される人気のある物理学のデモンストレーションです1,2,3,4,5。デモンストレーションでは、内径がボールの直径とほぼ等しいパイプのセクションにピンポンボールを配置します。パイプは両端をテープで密閉し、内圧2Torr未満まで排気します。パイプの一方の端にあるテープに穴が開いており、空気が大砲に入り、ボールに約5,000gのピーク加速度が発生します。大気圧だけで加速されたボールは、2m移動後、約300m/sの速度で大砲を出る。
PPCは一般的に大気圧の単純なデモンストレーションとして運用されていますが、複雑な圧縮性流れ物理学を示す装置でもあり、多くのオープンエンドの学生プロジェクトをもたらしました。ボールのダイナミクスは、壁の摩擦、ボールの周りの空気の漏れ、加速するボールによる衝撃波の形成などの二次的な要因の影響を受けます。ボールの大幅な加速により、ボールの前のチューブを下る大振幅の圧縮波が導入されます。これらの圧縮は局所的な音速よりも速く伝わり、圧縮波が急勾配になり、最終的には衝撃波6が形成されます。以前の研究では、ボールとチューブのテープ出口との間の衝撃波の反射によるチューブの出口での圧力の急速な上昇と、ボール2の出口の前に生じるテープの剥離を研究してきました。シングルミラーシュリーレンイメージング技術を使用した高速ビデオは、反射衝撃波に対するテープの応答と、PPC 7,8の出口でのテープの最終的な剥離を明らかにしました(ビデオ1)。したがって、PPCは、すべての年齢の聴衆を魅了する空気圧の単純なデモンストレーションとして、また実験室の設定で非常に詳細に研究できる複雑な流体物理学を示すデバイスの両方として機能します。
標準のPPCでは、ピンポン球の速度は音速によって制限されます。PPCのこの基本バージョンは、ボールを超音速にブーストするために使用される改造された大砲とともに、このホワイトペーパーの範囲でカバーされています。French et al.による以前の研究では、超音速ピンポン球の速度は、収束発散ノズル9,10,11を通る圧力駆動の流れを利用することによって達成されてきた。ここで紹介するSSPPCは、加圧(ドライバー)パイプを利用して、大気圧のみよりも大きな圧力差をピンポン球に提供します。薄いポリエステルダイアフラムは、ボールを含む排気された(駆動された)パイプからドライバーパイプを分離するために使用されます。このダイヤフラムは、十分なゲージ圧(ダイヤフラムの厚さに応じて通常5〜70psi)で破裂し、ピンポン球をマッハ1.4までの速度に加速します。超音速ピンポン球は、高速シャドウグラフイメージング技術7,12(ビデオ2)を使用して見られるように、定在衝撃波を生成します。
低出力(クラスII)HeNeレーザーを使用して、大砲の性能に関する光学診断研究を実施します。HeNeレーザービームは2つの経路に分割され、1つの経路は大砲の出口近くのアクリル窓のセットを横断し、2番目の経路は大砲の出口を通り過ぎて横断します。各パスは受光器で終端し、信号はデュアルチャンネルオシロスコープに表示されます。大砲の発射中に記録されたオシロスコープのトレースは、加速されたピンポン球の速度と、大砲からのボールの出口に先行する圧縮性の流れと衝撃波の両方に関する情報を明らかにします。各ビーム位置での直径40mmのピンポン球の速度は、ボールがビームをブロックする時間に直接関係しています。敏感な「ナイフエッジ」衝撃検出セットアップは、検出器の半分を黒い電気テープで覆い、テープの端をビーム2の中心に配置することによって達成されます。この設定では、圧縮可能な流れ誘起屈折率の屈折勾配によって生成されるHe-Neレーザービームのわずかなたわみが、オシロスコープトレースの電圧スパイクとしてはっきりと見えます。大砲の出口に向かって移動する衝撃波と反射された衝撃波はビームを反対方向に偏向させるため、正または負の電圧スパイクによって識別されます。
ここでは、最適化されたPPCとSSPPCの構築と利用、および光診断技術について説明します(図1、図2、および図3)。光学診断技術と測定は、過去数年間の研究を通じて開発されてきました1,2。

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high-speed optical diagnostics of a supersonic ping-pong cannon

従来のピンポン大砲(PPC)は、大気圧のみを使用して、排気されたパイプからほぼ音速までピンポンボールを発射する教育装置です。PPCの拡張バージョンであるSSPPCは、大気圧よりも高い圧力でボールを加速することにより、超音速を実現します。最適化されたPPCとSSPPCの構築と利用に関する指示を提供します。
光学診断は、大砲のダイナミクスを調査する目的で実装されます。パイプの出口近くの2つのアクリル窓から送られるHeNeレーザーは、受光センサーで終端されます。マイクロプロセッサは、ビームがピンポン球によって遮られる時間を測定し、ボールの速度を自動的に計算します。結果はすぐにLCDディスプレイに表示されます。 
光学ナイフエッジセットアップは、センサーでHeNeビームの一部を遮断することにより、衝撃波を検出する高感度の手段を提供します。衝撃波はビームの屈折誘発偏向を引き起こし、それは受光器からの電気信号の小さな電圧スパイクとして観察される。 
提示された方法は再現性が高く、実験室環境でのさらなる調査の機会を提供します。

ここでは、PPCとSSPPCの構築と利用、および衝撃特性評価と速度測定のための光学診断の実装について説明します。代表的な実験結果も提供します。PPCとSSPPCの完成したシステムと、必要なアクセサリを 図1 と 図2に示します。SSPPCはPPCの拡張バージョンであり、パイプの駆動加圧セクションがPPCの駆動パイプに接続されています。衝撃波のナイフエ?...

Watch this Scientific Journal Video about High-Speed Optical Diagnostics of a Supersonic Ping-Pong Cannon at JoVE.com

High-Speed Optical Diagnostics of a Supersonic Ping-Pong Cannon

超音速ピンポン砲(SSPPC)の構築方法と、ボール速度の測定と大砲の発射中に伝播する衝撃波の特性評価のための光学診断技術について説明します。

超音速ピンポン砲の高速光学診断

The traditional ping-pong cannon (PPC) is an educational apparatus that launches a ping-pong ball down an evacuated pipe to nearly sonic speeds using ...

超音速ピンポン砲の構築と操作、およびボール速度の測定と衝撃波の検出のための光学診断技術を提供します。光学ナイフエッジのセットアップは、レーザービームの小さなトラバース偏向に非常に敏感であり、大砲に関連する衝撃波を検出する手段を提供します。まず、フォトレシーバーとレーザーモジュールを15ボルトの電流制限電源とレーザー電源に接続して電力を供給します。次に、BNCケーブルを使用してフォトレシーバーをオシロスコープの2つのチャンネルに接続します。光学診断のセットアップでは、レーザーを製造された大砲に垂直に配置し、最初のビームをパイプ内のアクリル窓を通過し、2番目のビームを大砲の出口のすぐ外側に配置します。フォトレシーバーセンサーの半分に黒い電気テープを置き、ナイフエッジの衝撃検出セットアップを作成します。クリッピングを回避するには、ベースライン電圧が最大値の約50%になるようにナイフエッジのビーム位置を調整します。次に、オシロスコープの設定を調整して、2,000万個のデータポイントを収集します。水平スケールノブを使用して、データ収集速度を500メガヘルツに設定します。トリガーノブを回して、フォトレシーバーから取得した設定ベースラインをわずかに下回る電圧でトリップします。PPCを発射する前に、耳と目の保護具を着用してください。ピンポン球を大砲の出口に挿入し、パイプ入口近くの真空継手に当たるまで大砲の端に軽く吹き込みます。大砲の出口フランジとアクリルキャップを2枚の正方形のテープで密封します。レーザービームがナイフの端の中央に配置され、トリガーが正しく配置され、キャッチコンテナが固定されていることを確認してください。真空ポンプをオンにして、パイプを2Torr未満の減圧まで排気します。十分な真空に達したら、ブロードヘッドチップを使用して入り口のテープに穴を開けます。焼成後、真空ポンプの電源を切り、出口フランジとアクリルキャップから残っているテープをすべて取り除きます。超音速PPCを点火するには、ドライバーパイプをエアコンプレッサーに接続するバルブを閉じて、エアコンプレッサータンクを満たします。前に示したように、ボールを吹きます。超音速PPC出口フランジを密閉した後、2つのゴム製ガスケットの間に薄いプレカットポリエステルダイアフラムを挿入し、大砲のドライバーと被駆動セクションの間に配置します。4つのカムクランプを使用して2つのセクションを接続します。パイプ内の圧力が低下したら、エアコンプレッサーからドライバーパイプに圧力を解放し、ダイヤフラムが破裂し、ドライバーパイプ内の圧縮空気が排気された駆動パイプを満たすまで圧力を上げます。超音速PPC発射後、エアコンプレッサーと真空ポンプをオフにします。破裂したポリエステルダイヤフラムとテープを大砲から取り外します。大砲の発射プロセス全体で反射される伝播衝撃波は、時間に対する電圧の変化によって表されました。正または負のスパイクは信号の衝撃波の方向を示し、速度はボールがビームを遮断することによって生成される正方形のパルス幅によって計算されました。マイクロプロセッサを使用して、パイプ内部を横切るビームからの信号を処理し、大砲の出口近くのボール速度を自動的に計算して表示しました。オシロスコープのトレースは、超音速PPCのデュアルチャネル発射を示しました。上のトレースは、出口近くの大砲の内部を横断するビームを表しています。一方、下のトレースは、大砲を出た後にピンポン球の経路を横断するビームに対応します。カットオフ信号は、ボールが通過し、各ビームを遮ったことを示しました。マッハ数に対する圧力差のプロットは、0.001インチと0.002インチの厚さのダイアフラムが、ピンポン球を超音速に加速するのに十分な圧力差で破裂することが明らかになりました。ボール速度は一貫してマッハ1.3よりも大きく、厚さ0.002インチのダイヤフラムがありました。提示された超音速ピンポン大砲と光学診断は、デモンストレーション装置としても、その後の実験室実験のための装置としても、大砲の価値を高めます。

high-speed-optical-diagnostics-of-a-supersonic-ping-pong-cannon

Research

Education

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Unit 1

Kinematics of a Particle

SCIENTISTS IN ACTION

Construction and Testing of Coin Cells of Lithium Ion Batteries

Rechargeable lithium ion batteries have wide applications in electronics, where customers always demand more capacity and longer lifetime. Lithium ion batteries have also been considered to be used in electric and hybrid vehicles1 or even electrical grid stabilization systems2. All these applications simulate a dramatic increase in the research and development of battery materials3-7, including new materials3,8, doping9, nanostructuring10-13, coatings or surface modifications14-17 and novel binders18. Consequently, an increasing number of physicists, chemists and materials scientists have recently ventured into this area. Coin cells are widely used in research laboratories to test new battery materials; even for the research and development that target large-scale and high-power applications, small coin cells are often used to test the capacities and rate capabilities of new materials in the initial stage. 
 In 2010, we started a National Science Foundation (NSF) sponsored research project to investigate the surface adsorption and disordering in battery materials (grant no. DMR-1006515). In the initial stage of this project, we have struggled to learn the techniques of assembling and testing coin cells, which cannot be achieved without numerous help of other researchers in other universities (through frequent calls, email exchanges and two site visits). Thus, we feel that it is beneficial to document, by both text and video, a protocol of assembling and testing a coin cell, which will help other new researchers in this field. This effort represents the "Broader Impact" activities of our NSF project, and it will also help to educate and inspire students.
In this video article, we document a protocol to assemble a CR2032 coin cell with a LiCoO2 working electrode, a Li counter electrode, and (the mostly commonly used) polyvinylidene fluoride (PVDF) binder. To ensure new learners to readily repeat the protocol, we keep the protocol as specific and explicit as we can. However, it is important to note that in specific research and development work, many parameters adopted here can be varied. First, one can make coin cells of different sizes and test the working electrode against a counter electrode other than Li. Second, the amounts of C black and binder added into the working electrodes are often varied to suit the particular purpose of research; for example, large amounts of C black or even inert powder were added to the working electrode to test the "intrinsic" performance of cathode materials14. Third, better binders (other than PVDF) have also developed and used18. Finally, other types of electrolytes (instead of LiPF6) can also be used; in fact, certain high-voltage electrode materials will require the uses of special electrolytes7.

A protocol to construct and test coin cells of lithium ion batteries is described. The specific procedures of making a working electrode, preparing a counter electrode, assembling a cell inside a glovebox and testing the cell are presented.

リチウムイオン電池のコイン細胞の構築とテスト

Rechargeable lithium ion batteries have wide applications in electronics, where customers always demand more capacity and longer lifetime.  Lithium ion ...

工学

Fabricating Metamaterials Using the Fiber Drawing Method

Metamaterials are man-made composite materials, fabricated by assembling components much smaller than the wavelength at which they operate 1. They owe their electromagnetic properties to the structure of their constituents, instead of the atoms that compose them. For example, sub-wavelength metal wires can be arranged to possess an effective electric permittivity that is either positive or negative at a given frequency, in contrast to the metals themselves 2. This unprecedented control over the behaviour of light can potentially lead to a number of novel devices, such as invisibility cloaks 3, negative refractive index materials 4, and lenses that resolve objects below the diffraction limit 5. However, metamaterials operating at optical, mid-infrared and terahertz frequencies are conventionally made using nano- and micro-fabrication techniques that are expensive and produce samples that are at most a few centimetres in size 6-7. Here we present a fabrication method to produce hundreds of meters of metal wire metamaterials in fiber form, which exhibit a terahertz plasmonic response 8. We combine the stack-and-draw technique used to produce microstructured polymer optical fiber 9 with the Taylor-wire process 10, using indium wires inside polymethylmethacrylate (PMMA) tubes. PMMA is chosen because it is an easy to handle, drawable dielectric with suitable optical properties in the terahertz region; indium because it has a melting temperature of 156.6 &deg;C which is appropriate for codrawing with PMMA. We include an indium wire of 1 mm diameter and 99.99% purity in a PMMA tube with 1 mm inner diameter (ID) and 12 mm outside diameter (OD) which is sealed at one end. The tube is evacuated and drawn down to an outer diameter of 1.2 mm. The resulting fiber is then cut into smaller pieces, and stacked into a larger PMMA tube. This stack is sealed at one end and fed into a furnace while being rapidly drawn, reducing the diameter of the structure by a factor of 10, and increasing the length by a factor of 100. Such fibers possess features on the micro- and nano- scale, are inherently flexible, mass-producible, and can be woven to exhibit electromagnetic properties that are not found in nature. They represent a promising platform for a number of novel devices from terahertz to optical frequencies, such as invisible fibers, woven negative refractive index cloths, and super-resolving lenses.

Metamaterials at terahertz frequencies offer unique opportunities, but are challenging to fabricate in bulk. We adapt the fabrication procedure for microstructured polymer optical fibers to inexpensively fabricate metamaterials potentially on an industrial scale. We produce polymethylmethacrylate fibers containing ~10 &mu;m diameter indium wires separated by ~100 &mu;m, which exhibit a terahertz plasmonic response.

ファイバー描画法を用いたメタマテリアルの作製

Metamaterials are man-made composite materials, fabricated by assembling components much smaller than the wavelength at which they operate 1. They owe ...

Optical Trapping of Nanoparticles

Optical trapping is a technique for immobilizing and manipulating small objects in a gentle way using light, and it has been widely applied in trapping and manipulating small biological particles. Ashkin and co-workers first demonstrated optical tweezers using a single focused beam1. The single beam trap can be described accurately using the perturbative gradient force formulation in the case of small Rayleigh regime particles1. In the perturbative regime, the optical power required for trapping a particle scales as the inverse fourth power of the particle size. High optical powers can damage dielectric particles and cause heating. For instance, trapped latex spheres of 109 nm in diameter were destroyed by a 15 mW beam in 25 sec1, which has serious implications for biological matter2,3.
A self-induced back-action (SIBA) optical trapping was proposed to trap 50 nm polystyrene spheres in the non-perturbative regime4. In a non-perturbative regime, even a small particle with little permittivity contrast to the background can influence significantly the ambient electromagnetic field and induce a large optical force. As a particle enters an illuminated aperture, light transmission increases dramatically because of dielectric loading. If the particle attempts to leave the aperture, decreased transmission causes a change in momentum outwards from the hole and, by Newton's Third Law, results in a force on the particle inwards into the hole, trapping the particle. The light transmission can be monitored; hence, the trap can become a sensor. The SIBA trapping technique can be further improved by using a double-nanohole structure.
The double-nanohole structure has been shown to give a strong local field enhancement5,6. Between the two sharp tips of the double-nanohole, a small particle can cause a large change in optical transmission, thereby inducing a large optical force. As a result, smaller nanoparticles can be trapped, such as 12 nm silicate spheres7 and 3.4 nm hydrodynamic radius bovine serum albumin proteins8. In this work, the experimental configuration used for nanoparticle trapping is outlined. First, we detail the assembly of the trapping setup which is based on a Thorlabs Optical Tweezer Kit. Next, we explain the nanofabrication procedure of the double-nanohole in a metal film, the fabrication of the microfluidic chamber and the sample preparation. Finally, we detail the data acquisition procedure and provide typical results for trapping 20 nm polystyrene nanospheres.

The following setup approach details low power optical trapping of dielectric nanoparticles using a double-nanohole in metal film.

ナノ粒子の光トラッピング

Optical trapping is a technique for immobilizing and manipulating small objects in a gentle way using light, and it has been widely applied in trapping ...

High-resolution, High-speed, Three-dimensional Video Imaging with Digital Fringe Projection Techniques

Digital fringe projection (DFP) techniques provide dense 3D measurements of dynamically changing surfaces.&#160;Like the human eyes and brain, DFP uses triangulation between matching points in two views of the same scene at different angles to compute depth.&#160;However, unlike a stereo-based method, DFP uses a digital video projector to replace one of the cameras1. The projector rapidly projects a known sinusoidal pattern onto the subject, and the surface of the subject distorts these patterns in the camera&#8217;s field of view. Three distorted patterns (fringe images) from the camera can be used to compute the depth using triangulation.
Unlike other 3D measurement methods, DFP techniques lead to systems that tend to be faster, lower in equipment cost, more flexible, and easier to develop.&#160;DFP systems can also achieve the same measurement resolution as the camera.&#160;For this reason, DFP and other digital structured light techniques have recently been the focus of intense research (as summarized in1-5). Taking advantage of DFP, the graphics processing unit, and optimized algorithms, we have developed a system capable of 30&#160;Hz 3D video data acquisition, reconstruction, and display for over 300,000 measurement points per frame6,7.&#160;Binary defocusing DFP methods can achieve even greater speeds8.
Diverse applications can benefit from DFP techniques. Our collaborators have used our systems for facial function analysis9, facial animation10, cardiac mechanics studies11, and fluid surface measurements, but many other potential applications exist.&#160;This video will teach the fundamentals of DFP techniques and illustrate the design and operation of a binary defocusing DFP system.

This video describes the fundamentals of digital fringe projection techniques, which provide dense 3D measurements of dynamically changing surfaces.&#160;It also demonstrates the design and operation of a high-speed binary defocusing system based on these techniques.

デジタル干渉縞投影技術と高分解能、高速、三次元ビデオ画像

Digital fringe projection (DFP) techniques provide dense 3D measurements of dynamically changing surfaces.&#160;Like the human eyes and brain, DFP uses ...

Construction of a High Resolution Microscope with Conventional and Holographic Optical Trapping Capabilities

High resolution microscope systems with optical traps allow for precise manipulation of various refractive objects, such as dielectric beads 1 or cellular organelles 2,3, as well as for high spatial and temporal resolution readout of their position relative to the center of the trap. The system described herein has one such "traditional" trap operating at 980 nm. It additionally provides a second optical trapping system that uses a commercially available holographic package to simultaneously create and manipulate complex trapping patterns in the field of view of the microscope 4,5 at a wavelength of 1,064 nm. The combination of the two systems allows for the manipulation of multiple refractive objects at the same time while simultaneously conducting high speed and high resolution measurements of motion and force production at nanometer and piconewton scale.

The system described herein employs a traditional optical trap as well as an independent holographic optical trapping line, capable of creating and manipulating multiple traps. This allows for the creation of complex geometric arrangements of refractive particles while also permitting simultaneous high-speed, high-resolution measurements of the activity of biological enzymes.

従来のホログラフィック光トラッピング機能を備えた高分解能顕微鏡の構成

High resolution microscope systems with optical traps allow for precise manipulation of various refractive objects, such as dielectric beads 1 or cellular ...

High-speed Particle Image Velocimetry Near Surfaces

Multi-dimensional and transient flows play a key role in many areas of science, engineering, and health sciences but are often not well understood. The complex nature of these flows may be studied using particle image velocimetry (PIV), a laser-based imaging technique for optically accessible flows. Though many forms of PIV exist that extend the technique beyond the original planar two-component velocity measurement capabilities, the basic PIV system consists of a light source (laser), a camera, tracer particles, and analysis algorithms. The imaging and recording parameters, the light source, and the algorithms are adjusted to optimize the recording for the flow of interest and obtain valid velocity data. 
Common PIV investigations measure two-component velocities in a plane at a few frames per second. However, recent developments in instrumentation have facilitated high-frame rate (&gt; 1 kHz) measurements capable of resolving transient flows with high temporal resolution. Therefore, high-frame rate measurements have enabled investigations on the evolution of the structure and dynamics of highly transient flows. These investigations play a critical role in understanding the fundamental physics of complex flows.
A detailed description for performing high-resolution, high-speed planar PIV to study a transient flow near the surface of a flat plate is presented here. Details for adjusting the parameter constraints such as image and recording properties, the laser sheet properties, and processing algorithms to adapt PIV for any flow of interest are included.

A procedure for studying transient flows near boundaries using high-resolution, high-speed particle image velocimetry (PIV) is described here. PIV is a non-intrusive measurement technique applicable to any optically accessible flow by optimizing several parameter constraints such as the image and recording properties, the laser sheet properties, and analysis algorithms.

表面近くの高速粒子画像流速

Multi-dimensional and transient flows play a key role in many areas of science, engineering, and health sciences but are often not well understood. The ...

Visualization of High Speed Liquid Jet Impaction on a Moving Surface

Two apparatuses for examining liquid jet impingement on a high-speed moving surface are described: an air cannon device (for examining surface speeds between 0 and 25 m/sec) and a spinning disk device (for examining surface speeds between 15 and 100 m/sec). The air cannon linear traverse is a pneumatic energy-powered system that is designed to accelerate a metal rail surface mounted on top of a wooden projectile. A pressurized cylinder fitted with a solenoid valve rapidly releases pressurized air into the barrel, forcing the projectile down the cannon barrel. The projectile travels beneath a spray nozzle, which impinges a liquid jet onto its metal upper surface, and the projectile then hits a stopping mechanism. A camera records the jet impingement, and a pressure transducer records the spray nozzle backpressure. The spinning disk set-up consists of a steel disk that reaches speeds of 500 to 3,000 rpm via a variable frequency drive (VFD) motor. A spray system similar to that of the air cannon generates a liquid jet that impinges onto the spinning disc, and cameras placed at several optical access points record the jet impingement. Video recordings of jet impingement processes are recorded and examined to determine whether the outcome of impingement is splash, splatter, or deposition. The apparatuses are the first that involve the high speed impingement of low-Reynolds-number liquid jets on high speed moving surfaces. In addition to its rail industry applications, the described technique may be used for technical and industrial purposes such as steelmaking and may be relevant to high-speed 3D printing.

Two experimental devices for examining liquid jet impingement on a high-speed moving surface are described: an air cannon device and a spinning disk device. The apparatuses are used to determine optimal approaches to the application of liquid friction modifier (LFM) onto rail tracks for top-of-rail friction control.

表面移動に高速液体ジェット宿便の可視化

Two apparatuses for examining liquid jet impingement on a high-speed moving surface are described: an air cannon device (for examining surface speeds ...

Fabrication and Operation of a Nano-Optical Conveyor Belt

The technique of using focused laser beams to trap and exert forces on small particles has enabled many pivotal discoveries in the nanoscale biological and physical sciences over the past few decades. The progress made in this field invites further study of even smaller systems and at a larger scale, with tools that could be distributed more easily and made more widely available. Unfortunately, the fundamental laws of diffraction limit the minimum size of the focal spot of a laser beam, which makes particles smaller than a half-wavelength in diameter hard to trap and generally prevents an operator from discriminating between particles which are closer together than one half-wavelength. This precludes the optical manipulation of many closely-spaced nanoparticles and&#160;limits the&#160;resolution of optical-mechanical systems. Furthermore, manipulation using focused beams requires beam-forming or steering optics, which can be very bulky and expensive. To address these limitations in the system scalability of conventional optical trapping our lab has devised an alternative technique which utilizes near-field optics to move particles across a chip. Instead of focusing laser beams in the far-field, the optical near field of plasmonic resonators produces the necessary local optical intensity enhancement to overcome the restrictions of diffraction and manipulate particles at higher resolution. Closely-spaced resonators produce strong optical traps which can be addressed to mediate the hand-off of particles from one to the next in a conveyor-belt-like fashion. Here, we describe how to design and produce a conveyor belt using a gold surface patterned with plasmonic C-shaped resonators and how to operate it with polarized laser light to achieve super-resolution nanoparticle manipulation and transport. The nano-optical conveyor belt chip can be produced using lithography techniques and easily packaged and distributed.

The scalability and resolution of conventional optical manipulation techniques are limited by diffraction. We circumvent the diffraction limit and describe a method of optically transporting nanoparticles across a chip using a gold surface patterned with a path of closely spaced C-shaped plasmonic resonators.

ナノ光学コンベヤーベルトの作製と運用

The technique of using focused laser beams to trap and exert forces on small particles has enabled many pivotal discoveries in the nanoscale biological ...

Writing Bragg Gratings in Multicore Fibers

Fiber Bragg gratings in multicore fibers can be used as compact and robust filters in astronomical and other research and commercial applications. Strong suppression at a single wavelength requires that all cores have matching transmission profiles. These gratings cannot be inscribed using the same method as for single-core fibers because the curved surface of the cladding acts as a lens, focusing the incoming UV laser beam and causing variations in exposure between cores. Therefore we use an additional optical element to ensure that the beam shape does not change while passing through the cross-section of the multicore fiber. This consists of a glass capillary tube which has been polished flat on one side, which is then placed over the section of the fiber to be inscribed. The laser beam enters the fiber through the flat surface of the capillary tube and hence maintains its original dimensions. This paper demonstrates the improvements in core-to-core uniformity for a 7-core fiber using this method. The technique can be generalized to larger multicore fibers.

We describe a technique for inscribing identical fiber Bragg gratings into each core of a multicore fiber. This is achieved by introducing an additional surface into the optical path to mitigate lensing by the curved surface of the fiber cladding.

マルチコアファイバーブラッググレーティングを書きます

Fiber Bragg gratings in multicore fibers can be used as compact and robust filters in astronomical and other research and commercial applications. Strong ...

Compact Lens-less Digital Holographic Microscope for MEMS Inspection and Characterization

A micro-electro-mechanical-system (MEMS) is a widely used component in many industries, including energy, biotechnology, medical, communications, and automotive. However, effective inspection and characterization metrology systems are needed to ensure the functional reliability of MEMS. This study presents a system based on digital holography as a tool for MEMS metrology. Digital holography has gained increasing attention in the past 20 years. With the fast development and decreasing cost of sensor arrays, resolution of such systems has increased broadening potential applications. Thus, it has attracted attention from both research and industry sides as a potential reliable tool for industrial metrology. Indeed, by recording the interference pattern between an object beam (which contains sample height information) and a reference beam on a CCD camera, one can retrieve the quantitative phase information of an object. However, most of digital holographic systems are bulky and thus not easy to implement on industry production lines. The novelty of the system presented is that it is lens-less and thus very compact. In this study, it is shown that the Compact Digital Holographic Microscope (CDHM) can be used to evaluate several characteristics typically consider as criteria in MEMS inspections. The surface profiles of MEMS in both static and dynamic conditions are presented. Comparison with AFM is investigated to validate the accuracy of the CDHM.

We present a compact reflection digital holographic system (CDHM) for inspection and characterization of MEMS devices. A lens-less design using a diverging input wave providing natural geometrical magnification is demonstrated. Both static and dynamic studies are presented.

MEMS検査および特性評価のためのコンパクトなレンズレスデジタルホログラフィック顕微鏡

A micro-electro-mechanical-system (MEMS) is a widely used component in many industries, including energy, biotechnology, medical, communications, and ...