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. 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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. Commun. 2, 469 (2011).</li><li>Shi, X., Hesselink, L., Thornton, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrahigh+Light+Trans-+mission+through+a+C-shaped+Nanoaperture.">Ultrahigh Light Trans- mission through a C-shaped Nanoaperture.</a> Opt. 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.

El NOCB combina las poderosas fuerzas de captura y pequeño tamaño trampa de enfoques plasmónicas con la capacidad para el transporte de partículas, siempre disponibles sólo para las técnicas de centrado de vigas convencionales. Único en el NOCB, las propiedades de captura y transporte del sistema son el resultado de los patrones de la superficie y no de la conformación del haz de iluminación. Siempre que la iluminación es lo suficientemente brillante y su polarización o longitud de onda se puede modular, las ...

Capture, el interrogatorio y la manipulación de nanopartículas individuales son de creciente importancia en la nanotecnología. Las pinzas ópticas han convertido en una técnica de manipulación particularmente exitoso para experimentos en biología molecular 1-4 química 5-7 y nano-ensamblaje 7-10 donde han permitido experimentos innovadores tales como la medición de las propiedades mecánicas de las moléculas de ADN individuales 4 y la clasificación de células por sus propiedades ópticas 11,12. Descubrimientos sobre estas fronteras se abren el estudio de sistemas aún más pequeños, y dar paso a la ingeniería de nuevos productos y técnicas prácticamente beneficiosos. A su vez, esta tendencia impulsa la necesidad de nuevas técnicas para manipular partículas más pequeñas y rudimentarias. Además, hay un empuje para construir dispositivos &quot;lab-on-a-chip &#39;para llevar a cabo estas funciones de forma más barata y en un paquete más pequeño para traer pruebas químicas y biológicas dellaboratorio y en el campo para médicos y otros fines 13,14. Desafortunadamente, atrapamiento óptico convencional (COT) no puede satisfacer todas las demandas crecientes de la nanotecnología. COT opera sobre el mecanismo de utilizar una alta apertura numérica (NA) de lente de objetivo para llevar la luz láser a un foco apretado, creando un pico localizado en intensidad óptica y los altos gradientes en la energía del campo electromagnético. Estos gradientes de densidad de energía ejercen una fuerza neta sobre las partículas de dispersión de luz que en general los lleva hacia el centro del foco. Atrapando partículas más pequeñas requiere mayor potencia óptica o un enfoque más ajustado. Sin embargo, los rayos de luz enfocado obedecen el principio de difracción, lo que limita el tamaño mínimo del punto focal y coloca un límite superior en el gradiente de densidad de energía. Esto tiene dos consecuencias inmediatas: COT no pueden atrapar pequeños objetos de manera eficiente, y COT tiene problemas para discriminar entre partículas muy próximas entre sí, una resolución de capturalimitación conoce como el problema de los &quot;dedos gordos. Además, la aplicación de captura de partículas múltiples con COT requiere que los sistemas de la óptica de dirección del haz o moduladores espaciales de luz, componentes que aumentan drásticamente el costo y la complejidad de un sistema de captura óptica. Una forma de sortear las limitaciones fundamentales de los haces enfocados convencionales de luz, dijo para propagar en el campo lejano, es en lugar de explotar los gradientes de energía electromagnética óptico en el campo cercano. El campo cercano decae exponencialmente alejado de fuentes de campos electromagnéticos, lo que significa que no sólo es muy localizada a estas fuentes, pero también exhibe muy altos gradientes en su densidad de energía. Los cerca de campos de resonadores nano-metálicos, tales como aberturas bowtie, pilares nano, y grabados en forma de C, se ha demostrado que presentan concentraciones extraordinarias de energía electromagnética, reforzada por la acción plasmónica de oro y plata en casi infrlongitudes de onda ARED y ópticas. Estos resonadores se han utilizado para atrapar partículas extremadamente pequeñas con alta eficiencia y resolución de 15-22 de. Si bien esta técnica ha demostrado ser eficaz para atrapar las partículas pequeñas, también ha demostrado ser limitado en su capacidad de transportar partículas sobre el rango apreciable, lo cual es necesario si los sistemas de campo cercano son para interconectar con sistemas de campo lejano o microfluídica. Recientemente, nuestro grupo ha propuesto una solución a este problema. Cuando resonadores se colocan muy juntos, una partícula puede migrar, en principio, de una trampa óptica de campo cercano a la siguiente sin ser liberado de la superficie. La dirección de transporte se puede determinar si las trampas adyacentes se pueden activar y desactivar por separado. Una disposición lineal de tres o más resonadores direccionables, en el que cada resonador es sensible a una polarización o longitud de onda de luz diferente de la de sus vecinos, funciona como una cinta transportadora óptico, el transporte de nanopartiCiclos de más de una distancia de varias micras en un chip. El llamado &#39;nano-óptica Cinta transportadora&#39; (NOCB) es único entre los esquemas de captura resonador plasmónicas, ya que no sólo puede contener partículas en el lugar, pero también puede moverlos a alta velocidad a lo largo de pistas estampadas, recoger o dispersar partículas, mezclar y hacer cola, e incluso ordenarlos por propiedades tales como su movilidad 23. Todas estas funciones se controlan mediante la modulación de la polarización o longitud de onda de la iluminación, sin necesidad de óptica de dirección del haz. Como una trampa óptica de campo cercano, la NOCB atrapando resolución es mayor que la de trampas ópticas enfocada de haz convencionales, por lo que puede diferenciar entre partículas en las proximidades; porque utiliza una nanoestructura de metal para concentrar la luz en un atrapando así, es de bajo consumo, y no requiere de componentes ópticos caros, como un alto objetivo NA. Además, muchos NOCBs pueden funcionar en paralelo, a alta den embalajesidad, en el mismo sustrato, y 1 W de potencia puede pasar por encima de las aberturas 23 1200. Hemos demostrado recientemente la primera NOCB polarización impulsada, sin problemas propulsar una nanopartícula de ida y vuelta a lo largo de una pista 24 4.5 micras. En este artículo se presentan los pasos necesarios para diseñar y fabricar el dispositivo, ópticamente activarlo y reproducimos el experimento transporte. Esperamos que lo que esta técnica más ampliamente disponibles ayudará a cerrar la brecha de tamaño entre la óptica de microfluidos, campo lejano y dispositivos a nanoescala y experimentos.

<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 técnica de usar rayos láser enfocados para atrapar y ejercer fuerzas sobre las partículas pequeñas ha permitido a muchos descubrimientos fundamentales en las ciencias biológicas y físicas a nanoescala en los últimos decenios. Los avances realizados en este campo invita a un mayor estudio de los sistemas aún más pequeños y en mayor escala, con herramientas que puedan ser distribuidos con mayor facilidad y hacen más accesible. Desafortunadamente, las leyes fundamentales de difracción limitan el tamaño mínimo del punto focal de un rayo láser, lo que hace que las partículas más pequeñas que un medio de longitud de onda de diámetro duro para atrapar y generalmente evita que un operador de discriminar entre las partículas que son más juntos de una media -wavelength. Esto impide la manipulación óptica de muchos nanopartículas estrechamente espaciados y limita la resolución de sistemas óptico-mecánicos. Además, la manipulación utilizando haces enfocados requiere la óptica de formación de haz o de dirección, que pueden ser muy voluminosos y caros. Dirigirseestas limitaciones en la escalabilidad del sistema de captura óptica convencional nuestro laboratorio ha ideado una técnica alternativa que utiliza la óptica de campo cercano para mover partículas a través de un chip. En lugar de centrarse rayos láser en el campo lejano, el cercano campo óptico de resonadores plasmónicas produce la mejora intensidad óptica local, necesario para superar las restricciones de la difracción y manipular partículas a mayor resolución. Resonadores estrechamente espaciadas producen trampas ópticas fuertes que pueden ser abordados para mediar en el hand-off de partículas de uno a otro de una manera cinta transportadora similar. Aquí se describe cómo diseñar y producir una cinta transportadora usando una superficie de oro con dibujos de resonadores en forma de C plasmónicas y cómo operar con luz láser polarizada para lograr la manipulación nanopartícula super-resolución y el transporte. El chip cinta transportadora nano-óptica puede producirse usando técnicas de litografía y fácilmente empaquetado y distribuido.

Figura 7 es una imagen del dispositivo final. En el centro de la superficie de oro de 1 cm x 1 cm es la matriz de CSE y patrones transportadoras, que pueden ser apenas visto desde una vista en ángulo. La Figura 6 es una imagen de microscopía electrónica de barrido de un patrón de ejemplo CSE en el dispositivo final. El movimiento de las partículas de un perla de poliestireno 390 nm viajar a través de una cinta transportadora nano-óptica 5 micras de lo...

Watch this Scientific Journal Video about Fabrication and Operation of a Nano-Optical Conveyor Belt at JoVE.com

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.

Fabricación y operación de una banda transportadora nano-óptica

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

fabrication-and-operation-of-a-nano-optical-conveyor-belt

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SCIENTISTS IN ACTION

11.5K vistas.  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 método para fabricar nanoestructuras desconectados de plata en 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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Ingeniería

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.

Trampas ópticas de las nanopartículas

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.

La fabricación de nano-ingeniería óxidos conductores transparentes por deposición por láser pulsado

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.

Fabricación y Pruebas de microfluidos optomecánicos Osciladores

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.

La fabricación de nanoestructuras Atómicamente trazable

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.

La fabricación de 1-D de cristal fotónico cavidad en un nanofibras Uso de ablación inducida por láser de femtosegundo

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.

Fabricación de nanoestructuras magnéticas en membranas de nitruro de silicio para estudios de vórtice magnético usando técnicas de microscopía de transmisión

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.

Construcción y operación de un sistema del Motor rotatorio de Nanorod oro impulsado por la luz

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.

Diseño y fabricación de una fibra óptica hecha de agua

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.

Fabricación de canales de nanoaltura que incorporan la actuación de onda acústica superficial a través de niobato de litio para nanofluídicos acústicos

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