Name: fabrication and operation of a nano-optical conveyor belt
Uploaded: 2015-08-26T15:00:00.000+00:00
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Description: Watch this Scientific Journal Video about Fabrication and Operation of a Nano-Optical Conveyor Belt at JoVE.com

The authors would like to thank Professor Yuzuru Takashima at the University of Arizona for discussions on optical imaging, Mr. Karl Urbanek for assistance with high power lasers, and Max Yuen for discussions of Brownian motion. The authors send further thanks to Professor Kenneth Crozier at Harvard University for helpful discussions on optical trapping experiments. Funding was provided in part by the United States National Science Foundation (award number 1028372).

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E. 70 (3), 031108 (2004).</li><li>Eriksson, E., 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=A+Microfluidic+System+in+Combination+with+Optical+Tweezers+for+Analyzing+Rapid+and+Reversible+Cytological+Alterations+in+Single+Cells+upon+Environmental+Changes.">A Microfluidic System in Combination with Optical Tweezers for Analyzing Rapid and Reversible Cytological Alterations in Single Cells upon Environmental Changes.</a> Lab Chip. 7 (1), 71-76 (2007).</li><li>Applegate, R. W., Squier, J., Vestad, T., Oakey, J., Marr, D. W. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Optical Trapping, Manipulation, and Sorting of Cells and Colloids in Microfluidic Systems with Diode Laser. 12 (19), 4390-4398 (2004).</li><li>MacDonald, G. C., Spalding, G. C., Dholakia, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+Sorting+in+an+Optical+Lattice.">Microfluidic Sorting in an Optical Lattice.</a> Nature. 426 (6965), 421-424 (2003).</li><li>Neale, S. L., MacDonald, M. P., Dholakia, K., Krauss, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=All-optical+Control+of+Microfluidic+Components+using+Form.">All-optical Control of Microfluidic Components using Form.</a> Nat. Mater. 4 (7), 530-533 (2005).</li><li>Juan, M. L., Righini, M., Quidant, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasmon+Nano-optical+Tweezers.+.">Plasmon Nano-optical Tweezers. .</a> Nat. Photonics. 5 (6), 349-356 (2011).</li><li>Kwak, E. S., 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=Optical+Trapping+with+Integrated+Near-Field+Apertures.">Optical Trapping with Integrated Near-Field Apertures.</a> J. Phys. Chem. B. 108 (36), 13607-13612 (2004).</li><li>Righini, M., Zelenina, A. S., Girard, C., Quidant, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Parallel+and+Selective+Trapping+in+a+Patterned+Plasmonic+Landscape.">Parallel and Selective Trapping in a Patterned Plasmonic Landscape.</a> Nat. Phys. 3 (7), 477-480 (2007).</li><li>Zhang, W., Huang, L., Santschi, C., Martin, O. J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Trapping+and+Sensing+10+nm+Metal+Nanoparticles+using+Plasmonic+Dipole+Antennas.">Trapping and Sensing 10 nm Metal Nanoparticles using Plasmonic Dipole Antennas.</a> Nano Lett. 10 (3), 1006-1011 (2010).</li><li>Wang, K., Schonbrun, E., Steinvurzel, P., Crozier, K. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Trapping+and+Rotating+Nanoparticles+using+a+Plasmonic+Nano-tweezer+with+an+Integrated+Heat+Sink.">Trapping and Rotating Nanoparticles using a Plasmonic Nano-tweezer with an Integrated Heat Sink.</a> Nat. 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Lett. 28 (15), 1320-1322 (2003).</li><li>Chen, K., Lee, A., Hung, C., Huang, J., Yang, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transport+and+Trapping+in+Two-Dimensional+Nanoscale+Plasmonic+Optical+Lattice.">Transport and Trapping in Two-Dimensional Nanoscale Plasmonic Optical Lattice.</a> Nano Lett. 13, 4118-4122 (2013).</li><li>Cuche, A., 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=Sorting+Nanoparticles+with+Intertwined+Plasmonic+and+Thermo-Hydrodynamical+Forces.">Sorting Nanoparticles with Intertwined Plasmonic and Thermo-Hydrodynamical Forces.</a> Nano Lett. 13, 4230-4235 (2013).</li><li>Hansen, P., Zheng, Y., Ryan, J., Hesselink, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nano-Optical+Conveyor+Belt,+Part+I:+Theory.">Nano-Optical Conveyor Belt, Part I: Theory.</a> Nano Lett. 14, 2965-2970 (2014).</li><li>Zheng, Y., 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=Nano-Optical+Conveyor+Belt,+Part+II:+Demonstration+of+Handoff+Between+Near-Field+Optical+Traps.">Nano-Optical Conveyor Belt, Part II: Demonstration of Handoff Between Near-Field Optical Traps.</a> Nano Lett. 14, 2971-2976 (2014).</li><li>Vogel, N., Zieleniecki, J., Koper, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=As+flat+as+it+gets:+Ultrasmooth+Surfaces+from+Template-stripping+Procedures.">As flat as it gets: Ultrasmooth Surfaces from Template-stripping Procedures.</a> Nanoscale. 4 (13), 3820-3832 (2012).</li><li>Zhu, X., 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=Ultrafine+and+Smooth+Full+Metal+Nanostructures+for+Plasmonics.">Ultrafine and Smooth Full Metal Nanostructures for Plasmonics.</a> Adv. Mater. 22 (39), 4345-4349 (2010).</li><li>Kaleli, B., 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=Electron+Beam+Lithography+of+HSQ+and+PMMA+Resists+and+Importance+of+their+Properties+to+Link+the+Nano+World+to+the+Micro+World.">Electron Beam Lithography of HSQ and PMMA Resists and Importance of their Properties to Link the Nano World to the Micro World.</a> , 105-108 (2010).</li></ol>

The authors have nothing to disclose.

Il NOCB combina le potenti forze di cattura e le piccole dimensioni trappola di approcci plasmoniche con la capacità di trasportare particelle, lungo disponibile solo per le tecniche convenzionali mirato a fascio. Unico al NOCB, le proprietà di cattura e di trasporto del sistema sono il risultato di patterning superficiale e non di modellare il fascio di illuminazione. Fornito l&#39;illuminazione è abbastanza luminoso e la sua polarizzazione o lunghezza d&#39;onda può essere modulata, particelle può essere tenuto o...

La cattura, l&#39;interrogatorio e la manipolazione di singole nanoparticelle sono di crescente importanza nel campo delle nanotecnologie. Pinzette ottiche sono diventati una tecnica di manipolazione particolarmente efficace per esperimenti di biologia molecolare 1-4, 5-7 e chimica nano-assemblaggio 7-10, dove sono abilitati esperimenti innovativi come la misura delle proprietà meccaniche di singole molecole di DNA 4 e l&#39;ordinamento delle cellule dalle loro proprietà ottiche 11,12. Scoperte su queste frontiere si aprono lo studio di sistemi ancora più piccoli, e fanno strada alla progettazione di nuovi prodotti e tecniche praticamente benefiche. A sua volta, questa tendenza spinge la necessità di nuove tecniche per manipolare piccole particelle, più rudimentali. Inoltre, vi è una spinta per costruire dispositivi &#39;lab-on-a-chip &quot;per eseguire queste funzioni più a buon mercato e in un pacchetto più piccolo per portare test chimici e biologici dallaboratorio e nel campo medico e per altri scopi 13,14. Purtroppo, intrappolamento ottico convenzionale (COT) non può soddisfare tutte le richieste crescenti di nanotecnologia. COT opera sul meccanismo di utilizzare un elevato apertura numerica (NA) lente obiettivo per portare la luce laser per un fuoco stretto, creando un picco localizzato in intensità ottica e alti gradienti di energia campo elettromagnetico. Questi gradienti di densità di energia esercitano una forza netta sul particelle di luce-dispersione che generalmente li attira verso il centro del fuoco. Intrappolando le particelle più piccole richiede potenza ottica superiore o una maggiore attenzione. Tuttavia, fasci di luce concentrato obbediscono al principio della diffrazione, che limita la dimensione minima della macchia focale e pone un limite superiore al gradiente di densità di energia. Questo ha due conseguenze immediate: COT non può trattenere piccoli oggetti in modo efficiente, e COT ha difficoltà a discriminare tra particelle ravvicinati, risoluzione di catturalimitazione nota come problema le &quot;dita grasse. Inoltre, l&#39;implementazione multipla cattura particella con COT richiede sistemi di ottica fascio sterzanti o modulatori di luce spaziali, componenti che aumentano drasticamente il costo e la complessità di un sistema di intrappolamento ottico. Un modo per aggirare le limitazioni fondamentali convenzionali fasci focalizzati di luce, detto propagare nel campo lontano, è quello di sfruttare invece i gradienti di energia elettromagnetica ottica nel campo vicino. Il campo vicino decade esponenzialmente lontano da fonti di campi elettromagnetici, il che significa che non solo è altamente localizzata a queste fonti, ma espone anche molto elevati gradienti nella sua densità di energia. I vicini campi di risonatori nano-metallici, quali aperture bowtie, pilastri nano, e incisioni a forma di C, hanno dimostrato di esporre straordinarie concentrazioni di energia elettromagnetica, ulteriormente rafforzata dall&#39;azione plasmonica di oro e argento a quasi infrle lunghezze d&#39;onda ARED e ottici. Questi risonatori sono stati utilizzati per intrappolare particelle estremamente piccole ad alta efficienza e la risoluzione 15-22. Sebbene questa tecnica si è dimostrata efficace in grado di intrappolare piccole particelle, ma ha anche dimostrato di essere limitato nella sua capacità di trasportare particelle range sensibile, che è necessaria se i sistemi in campo vicino sono di interfacciarsi con sistemi di campo lontano o microfluidica. Recentemente, il nostro gruppo ha proposto una soluzione a questo problema. Quando risonatori sono posizionati molto vicini tra loro, una particella può in linea di principio migrare da un campo vicino trappola ottica all&#39;altro senza essere rilasciato dalla superficie. La direzione di trasporto può essere determinato se trappole adiacenti possono essere accesi e spenti separatamente. Un array lineare di tre o più risonatori indirizzabili, in cui ciascun risonatore è sensibile ad una polarizzazione o lunghezza d&#39;onda di luce differente da quella dei suoi vicini, funziona come un nastro trasportatore ottica, trasportando nanopartiCicli su una distanza di alcuni micron su un chip. Il cosiddetto &#39;Nano-ottica Nastro trasportatore&#39; (NOCB) è unico tra i regimi risonatore di cattura plasmoniche, in quanto non solo può contenere particelle in luogo, ma può anche spostarli ad alta velocità lungo le piste fantasia, raccogliere o disperdere le particelle, mescolare e coda, e persino dalle proprietà ordinarli come la mobilità 23. Tutte queste funzioni sono controllate modulando la polarizzazione o lunghezza d&#39;onda di illuminazione, senza necessità per l&#39;ottica del fascio sterzanti. Come trappola ottica in campo vicino, il NOCB intrappolando risoluzione è superiore a quella dei tradizionali focalizzato travi trappole ottiche, in modo che possa distinguere tra particelle in prossimità; perché utilizza una nanostruttura metallica per concentrare la luce in una cattura bene, è a basso consumo, e non richiede componenti ottici costosi come obiettivo elevata NA. Inoltre, molti NOCBs possono funzionare in parallelo, ad alta den imballaggiosity, sullo stesso substrato, e 1 W di potenza può guidare più di 1200 aperture 23. Abbiamo recentemente dimostrato la prima NOCB polarizzazione-driven, senza intoppi spingendo una nanoparticella avanti e indietro lungo un 4,5 micron pista 24. In questo articolo vi presentiamo le misure necessarie per progettare e fabbricare il dispositivo, otticamente attivarlo e riproduciamo l&#39;esperimento di trasporto. Speriamo che rendendo questa tecnica più ampiamente disponibile contribuirà a colmare il divario tra le dimensioni ottica microfluidica, in campo lontano, e dispositivi in ​​nanoscala e sperimentazioni.

<table><tbody><tr><td>HSQ e-beam resist</td><td>Dow Corning</td><td>XR-1541-006</td><td></td></tr><tr><td>PMMA</td><td>MicroChem</td><td>950A2 M230002</td><td></td></tr><tr><td>Fast curing optical adhesive</td><td>Norland Optical Adhesive</td><td>NOA 81</td><td></td></tr><tr><td>Fluorescent carboxyl microspheres</td><td>Bangs Laboratories</td><td>FC02F, FC03F</td><td></td></tr><tr><td>Fluorescent carboxylate-modified microspheres</td><td>Molecular Probes</td><td>F-8888</td><td></td></tr><tr><td>Quartz slide</td><td>SPI Supplies</td><td>1020-AB</td><td></td></tr><tr><td>Inverted fluorescent microscope</td><td>Nikon</td><td>ECLIPSE TE2000-U</td><td></td></tr><tr><td>Nd:YAG laser</td><td>Lightwave Electronics</td><td>221-HD-V04</td><td></td></tr><tr><td>sCMOS camera</td><td>PCO</td><td>EDGE55</td><td></td></tr><tr><td>CCD camera</td><td>Watec</td><td>WAT-120N</td><td></td></tr><tr><td>Zero-order half-wave plate</td><td>Thorlabs</td><td>WPH05M-1064</td><td></td></tr><tr><td>Triton X-100</td><td>Sigma-Aldrich</td><td>T8787</td><td></td></tr><tr><td>Distilled water</td><td>Invitrogen</td><td>10977-023</td><td></td></tr><tr><td>Si Wafer</td><td>Silicon Quest International</td><td>708069</td><td></td></tr><tr><td>Optical lenses</td><td>Thorlabs</td><td></td><td></td></tr></tbody></table>

fabrication and operation of a nano-optical conveyor belt

La tecnica di utilizzare raggi laser mirati per intrappolare e esercitare forze in piccole particelle ha permesso a molte scoperte cardine nelle scienze biologiche e fisiche nanoscala nel corso degli ultimi decenni. I progressi compiuti in questo campo invita ulteriore studio di sistemi ancora più piccoli e ad una scala più ampia, con strumenti che potrebbero essere distribuiti più facilmente e reso più ampiamente disponibile. Purtroppo, le leggi fondamentali della diffrazione limitano la dimensione minima del punto focale di un fascio laser, il che rende le particelle più piccole di una mezza lunghezza d&#39;onda di diametro difficile da intrappolare e generalmente impedisce all&#39;operatore di discriminare tra le particelle che sono più vicini della metà -wavelength. Ciò preclude la manipolazione ottica di molte nanoparticelle ravvicinati e limita la risoluzione di sistemi ottici-meccanici. Inoltre, la manipolazione mediante fasci focalizzati richiede ottica beam-forming e di sterzo, che possono essere molto ingombranti e costosi. Indirizzarequeste limitazioni nella scalabilità del sistema di intrappolamento ottico convenzionale nostro laboratorio ha messo a punto una tecnica alternativa che utilizza l&#39;ottica di campo vicino per spostare particelle attraverso un chip. Invece di concentrarsi raggi laser nel campo lontano, il vicino campo ottico di risonatori plasmoniche produce la necessaria valorizzazione locale intensità ottica per superare le restrizioni di diffrazione e manipolare particelle a più alta risoluzione. Risonatori ravvicinate producono forti trappole ottiche che possono essere indirizzati a mediare l&#39;hand-off di particelle da una all&#39;altra in un modo nastro trasportatore-like. Qui, descriviamo come progettare e produrre un nastro trasportatore con una superficie d&#39;oro fantasia con plasmoniche risonatori a forma di C e come farlo funzionare con luce laser polarizzata per ottenere super-risoluzione manipolazione delle nanoparticelle e dei trasporti. Il convogliatore trucioli cinghia nano-ottica può essere prodotto con tecniche di litografia e facilmente confezionato e distribuito.

La figura 7 è una foto del dispositivo finale. Al centro della superficie d&#39;oro 1 cm x 1 cm è la matrice di CSE e trasportatori modelli che possono essere poco visibili guardando un angolo vista. Figura 6 è una immagine al microscopio elettronico a scansione di una sequenza di esempio CSE sul dispositivo finale. Il movimento delle particelle di 390 nm in polistirolo viaggia attraverso un nastro trasportatore nano-ottica 5 micron di lunghezza ?...

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Fabrication and Operation of a Nano-Optical Conveyor Belt

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.

Fabbricazione e funzionamento di un nano-ottica Nastro trasportatore

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

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11.5K Views.  Stanford University. 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.

Video: Fabrication and Operation of a Nano-Optical Conveyor Belt

A Method to Fabricate Disconnected Silver Nanostructures in 3D

The standard nanofabrication toolkit includes techniques primarily aimed at creating 2D patterns in dielectric media. Creating metal patterns on a submicron scale requires a combination of nanofabrication tools and several material processing steps. For example, steps to create planar metal structures using ultraviolet photolithography and electron-beam lithography can include sample exposure, sample development, metal deposition, and metal liftoff. To create 3D metal structures, the sequence is repeated multiple times. The complexity and difficulty of stacking and aligning multiple layers limits practical implementations of 3D metal structuring using standard nanofabrication tools. Femtosecond-laser direct-writing has emerged as a pre-eminent technique for 3D nanofabrication.1,2 Femtosecond lasers are frequently used to create 3D patterns in polymers and glasses.3-7 However, 3D metal direct-writing remains a challenge. Here, we describe a method to fabricate silver nanostructures embedded inside a polymer matrix using a femtosecond laser centered at 800 nm. The method enables the fabrication of patterns not feasible using other techniques, such as 3D arrays of disconnected silver voxels.8 Disconnected 3D metal patterns are useful for metamaterials where unit cells are not in contact with each other,9 such as coupled metal dot10,11or coupled metal rod12,13 resonators. Potential applications include negative index metamaterials, invisibility cloaks, and perfect lenses.
In femtosecond-laser direct-writing, the laser wavelength is chosen such that photons are not linearly absorbed in the target medium. When the laser pulse duration is compressed to the femtosecond time scale and the radiation is tightly focused inside the target, the extremely high intensity induces nonlinear absorption. Multiple photons are absorbed simultaneously to cause electronic transitions that lead to material modification within the focused region. Using this approach, one can form structures in the bulk of a material rather than on its surface.
Most work on 3D direct metal writing has focused on creating self-supported metal structures.14-16 The method described here yields sub-micrometer silver structures that do not need to be self-supported because they are embedded inside a matrix. A doped polymer matrix is prepared using a mixture of silver nitrate (AgNO3), polyvinylpyrrolidone (PVP) and water (H2O). Samples are then patterned by irradiation with an 11-MHz femtosecond laser producing 50-fs pulses. During irradiation, photoreduction of silver ions is induced through nonlinear absorption, creating an aggregate of silver nanoparticles in the focal region. Using this approach we create silver patterns embedded in a doped PVP matrix. Adding 3D translation of the sample extends the patterning to three dimensions.

Femtosecond-laser direct-writing is frequently used to create three-dimensional (3D) patterns in polymers and glasses. However, patterning metals in 3D remains a challenge. We describe a method for fabricating silver nanostructures embedded inside a polymer matrix using a femtosecond laser centered at 800 nm.

Un metodo per fabbricare nanostrutture d&#39;argento disconnesse in 3D

The standard nanofabrication toolkit includes  techniques primarily aimed at creating 2D patterns in dielectric media. Creating  metal patterns on a ...

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Ingegneria

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.

Trapping ottica di nanoparticelle

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 ...

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.

Fabbricazione di nano-ingegneria trasparenti Ossidi Conducting da 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, ...

Fabrication and Testing of Microfluidic Optomechanical Oscillators

Cavity optomechanics experiments that parametrically couple the phonon modes and photon modes have been investigated in various optical systems including microresonators. However, because of the increased acoustic radiative losses during direct liquid immersion of optomechanical devices, almost all published optomechanical experiments have been performed in solid phase. This paper discusses a recently introduced hollow microfluidic optomechanical resonator. Detailed methodology is provided to fabricate these ultra-high-Q microfluidic resonators, perform optomechanical testing, and measure radiation pressure-driven breathing mode and SBS-driven whispering gallery mode parametric vibrations. By confining liquids inside the capillary resonator, high mechanical- and optical- quality factors are simultaneously maintained.

Parametric optomechanical excitations have recently been experimentally demonstrated in microfluidic optomechanical resonators by means of optical radiation pressure and stimulated Brillouin scattering. This paper describes the fabrication of these microfluidic resonators along with methodologies for generating and verifying optomechanical oscillations.

Fabbricazione e la sperimentazione di microfluidici optomechanical Oscillatori

Cavity optomechanics experiments that parametrically couple the phonon modes and photon modes have been investigated in various optical systems including ...

Atomically Traceable Nanostructure Fabrication

Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the entire fabrication process being used in order to maintain exquisite control over both feature size and feature density. Here, we demonstrate a method for tracking atomically resolved and controlled structures from initial template definition through final nanostructure metrology, opening up a pathway for top-down atomic control over nanofabrication. Hydrogen depassivation lithography is the first step of the nanoscale fabrication process followed by selective atomic layer deposition of up to 2.8 nm of titania to make a nanoscale etch mask. Contrast with the background is shown, indicating different mechanisms for growth on the desired patterns and on the H passivated background. The patterns are then transferred into the bulk using reactive ion etching to form 20 nm tall nanostructures with linewidths down to ~6 nm. To illustrate the limitations of this process, arrays of holes and lines are fabricated. The various nanofabrication process steps are performed at disparate locations, so process integration is discussed. Related issues are discussed including using fiducial marks for finding nanostructures on a macroscopic sample and protecting the chemically reactive patterned Si(100)-H surface against degradation due to atmospheric exposure.

We report a protocol for combining the atomic metrology of the Scanning Tunneling Microscope for surface patterning with selective Atomic Layer Deposition and Reactive Ion Etching. Using a robust process involving numerous atmospheric exposures and transport, 3D nanostructures with atomic metrology are fabricated.

Atomicamente tracciabile nanostrutture

Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the entire fabrication process ...

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.

Fabbricazione di 1-D Photonic cristallo cavità su una nanofibre Utilizzando ablazione laser a femtosecondi-indotta

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

Fabrication of Magnetic Nanostructures on Silicon Nitride Membranes for Magnetic Vortex Studies Using Transmission Microscopy Techniques

Electron and x-ray magnetic microscopies allow for high-resolution magnetic imaging down to tens of nanometers. However, the samples need to be prepared on transparent membranes which are very fragile and difficult to manipulate. We present processes for the fabrication of samples with magnetic micro- and nanostructures with spin configurations forming magnetic vortices suitable for Lorentz transmission electron microscopy and magnetic transmission x-ray microscopy studies. The samples are prepared on silicon nitride membranes and the fabrication consists of a spin coating, UV and electron-beam lithography, the chemical development of the resist, and the evaporation of the magnetic material followed by a lift-off process forming the final magnetic structures. The samples for the Lorentz transmission electron microscopy consist of magnetic nanodiscs prepared in a single lithography step. The samples for the magnetic x-ray transmission microscopy are used for time-resolved magnetization dynamic experiments, and magnetic nanodiscs are placed on a waveguide which is used for the generation of repeatable magnetic field pulses by passing an electric current through the waveguide. The waveguide is created in an extra lithography step.

A protocol for the fabrication of magnetic micro- and nanostructures with spin configurations forming magnetic vortices suitable for transmission electron microscopy (TEM) and magnetic transmission x-ray microscopy (MTXM) studies is presented.

Fabbricazione di nanostrutture magnetiche sulle membrane di nitruro di silicio per studi di vortice magnetico utilizzando tecniche di microscopia di trasmissione

Electron and x-ray magnetic microscopies allow for high-resolution magnetic imaging down to tens of nanometers. However, the samples need to be prepared ...

Construction and Operation of a Light-driven Gold Nanorod Rotary Motor System

The possibility to generate and measure rotation and torque at the nanoscale is of fundamental interest to the study and application of biological and artificial nanomotors and may provide new routes towards single cell analysis, studies of non-equilibrium thermodynamics, and mechanical actuation of nanoscale systems. A facile way to drive rotation is to use focused circularly polarized laser light in optical tweezers. Using this approach, metallic nanoparticles can be operated as highly efficient scattering-driven rotary motors spinning at unprecedented rotation frequencies in water.
In this protocol, we outline the construction and operation of circularly-polarized optical tweezers for nanoparticle rotation and describe the instrumentation needed for recording the Brownian dynamics and Rayleigh scattering of the trapped particle. The rotational motion and the scattering spectra provides independent information on the properties of the nanoparticle and its immediate environment. The experimental platform has proven useful as a nanoscopic gauge of viscosity and local temperature, for tracking morphological changes of nanorods and molecular coatings, and as a transducer and probe of photothermal and thermodynamic processes.

Plasmonic gold nanorods can be trapped in liquids and rotated at kHz frequencies using circularly-polarized optical tweezers. Introducing tools for Brownian dynamics analysis and light scatteringspectroscopy leads to a powerful system for research and application in numerous fields of science.

Costruzione e funzionamento di un sistema motore basato su luce oro Nanorod Rotary

The possibility to generate and measure rotation and torque at the nanoscale is of fundamental interest to the study and application of biological and ...

Design and Fabrication of an Optical Fiber Made of Water

In this report, an optical fiber of which the core is made solely of water, while the cladding is air, is designed and manufactured. In contrast with solid-cladding devices, capillary oscillations are not restricted, allowing the fiber walls to move and vibrate. The fiber is constructed by a high direct current (DC) voltage of several thousand volts (kV) between two water reservoirs that creates a floating water thread, known as a water bridge. Through the choice of micropipettes, it is possible to control the maximal diameter and length of the fiber. Optical fiber couplers, at both sides of the bridge, activate it as an optical waveguide, allowing researchers to monitor the water fiber capillary body waves through transmission modulation and, therefore, deducing changes in surface tension.
Co-confining two important wave types, capillary and electromagnetic, opens a new path of research in the interactions between light and liquid-wall devices. Water-walled microdevices are a million times softer than their solid counterparts, accordingly improving the response to minute forces.

This protocol describes the design and manufacture of a water bridge and its activation as a water fiber. The experiment demonstrates that capillary resonances of the water fiber modulate its optical transmission.

Progettazione e fabbricazione di una fibra ottica fatta di acqua

In this report, an optical fiber of which the core is made solely of water, while the cladding is air, is designed and manufactured. In contrast with ...

Fabrication of Nanoheight Channels Incorporating Surface Acoustic Wave Actuation via Lithium Niobate for Acoustic Nanofluidics

Controlled nanoscale manipulation of fluids is known to be exceptionally difficult due to the dominance of surface and viscous forces. Megahertz-order surface acoustic wave (SAW) devices generate tremendous acceleration on their surface, up to 108 m/s2, in turn responsible for many of the observed effects that have come to define acoustofluidics: acoustic streaming and acoustic radiation forces. These effects have been used for particle, cell, and fluid manipulation at the microscale, although more recently SAW has been used to produce similar phenomena at the nanoscale through an entirely different set of mechanisms. Controllable nanoscale fluid manipulation offers a broad range of opportunities in ultrafast fluid pumping and biomacromolecule dynamics useful for physical and biological applications. Here, we demonstrate nanoscale-height channel fabrication via room-temperature lithium niobate (LN) bonding integrated with a SAW device. We describe the entire experimental process including nano-height channel fabrication via dry etching, plasma-activated bonding on lithium niobate, the appropriate optical setup for subsequent imaging, and SAW actuation. We show representative results for fluid capillary filling and fluid draining in a nanoscale channel induced by SAW. This procedure offers a practical protocol for nanoscale channel fabrication and integration with SAW devices useful to build upon for future nanofluidics applications.

We demonstrate fabrication of nanoheight channels with the integration of surface acoustic wave actuation devices upon lithium niobate for acoustic nanofluidics via liftoff photolithography, nano-depth reactive ion etching, and room-temperature plasma surface-activated multilayer bonding of single-crystal lithium niobate, a process similarly useful for bonding lithium niobate to oxides.

Fabbricazione di canali Nanoheight che incorporano l'atuazione delle onde acustiche superficiali tramite Litio Niobate per la Nanofluidica acustica

Controlled nanoscale manipulation of fluids is known to be exceptionally difficult due to the dominance of surface and viscous forces. Megahertz-order ...