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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The authors have nothing to disclose.

O NOCB combina as forças de armadilhagem fortes e tamanho pequeno armadilha de abordagens plasmonic com a capacidade para o transporte de partículas, a longo disponível somente para as técnicas de feixe focalizado convencionais. Exclusivo para o NOCB, as propriedades de captura e transporte do sistema são o resultado de padrões de superfície e não de moldar o feixe de iluminação. Desde que a iluminação é brilhante o suficiente e sua polarização ou comprimento de onda pode ser modulada, as partículas pode...

Capture, interrogatório e manipulação de nanopartículas individuais são de importância crescente na nanotecnologia. Pinças ópticas tornaram-se uma técnica de manipulação particularmente bem sucedido para experimentos em biologia molecular 1-4, 5-7 e química nano-montagem 7-10, onde eles permitiram que experiências inovadoras, tais como a medição das propriedades mecânicas de moléculas de DNA de solteiro 4 e a ordenação das células por suas propriedades ópticas 11,12. Descobertas sobre essas fronteiras abrir o estudo de sistemas ainda menores, e eles abrir caminho para a engenharia de novos produtos e técnicas praticamente benéficos. Por sua vez, esta tendência impulsiona a necessidade de novas técnicas para manipular mais rudimentares, partículas menores. Além disso, há uma pressão para construir dispositivos &quot;lab-on-a-chip&quot; para executar essas funções de forma mais barata e numa embalagem mais pequena, a fim de trazer os testes químicos e biológicos para fora dolaboratório e no campo para médicos e outros fins 13,14. Infelizmente, captura óptica convencional (COT) não pode atender a todas as demandas de crescimento da nanotecnologia. COT opera sobre o mecanismo de utilizar uma elevada abertura numérica (NA) lente objectiva para trazer luz laser para um foco apertado, criando um pico localizado em intensidade óptica e gradientes elevados em energia do campo electromagnético. Estes gradientes de densidade de energia exercem uma força resultante sobre partículas de dispersão da luz que geralmente chama-los em direcção ao centro do foco. Prendendo partículas menores exige potência óptica superior ou um foco mais apertado. No entanto, os feixes de luz focalizado obedecer o princípio da difracção, que limita o tamanho mínimo do ponto focal e coloca um limite superior do gradiente de densidade de energia. Isso tem duas consequências imediatas: COT não pode reter pequenos objetos de forma eficiente, e COT tem dificuldade para discriminar entre as partículas espaçados, uma resolução trappinglimitação conhecida como o problema dos dedos gordos &quot;. Além disso, a implementação de múltiplos aprisionamento de partículas com COT requer sistemas de óptica de orientação de feixe de luz ou moduladores espaciais, componentes que aumentam drasticamente o custo ea complexidade de um sistema de captura óptica. Uma maneira de contornar as limitações fundamentais de vigas focadas convencionais de luz, disse a propagar no campo agora, é a vez explorar os gradientes de energia eletromagnética óptica no campo próximo. O próximo campo decai exponencialmente a partir de fontes fora dos campos electromagnéticos, o que significa que não só é altamente localizada a estas fontes, mas também exibe muito elevados gradientes na sua densidade de energia. Os próximos campos de ressonadores nano-metálicos, como aberturas bowtie, nano colunas e as gravuras em forma de C, foram mostrados para expor extraordinária concentração de energia eletromagnética, reforçada pela ação plasmonic de ouro e prata a quase infrcomprimentos de onda ópticos e ARED. Estes ressoadores ter sido usado para prender partículas extremamente pequenas com elevada eficiência e resolução 15-22. Embora esta técnica tem se mostrado eficaz na captura de partículas pequenas, ele também provou ser limitado em sua capacidade para o transporte de partículas sobre a escala apreciável, o que é necessário se os sistemas de campo próximo são a interface com sistemas de campo distante ou microfluídica. Recentemente, o nosso grupo propôs uma solução para este problema. Quando ressonadores são colocados muito próximos entre si, uma partícula pode, em princípio, migrar de um campo próximo armadilha óptica para o próximo sem ser liberado a partir da superfície. A direcção do transporte pode ser determinado se armadilhas adjacentes podem ser ligados e desligados separadamente. Uma cadeia linear de três ou mais ressonadores endereçáveis, em que cada um ressonador é sensível a um comprimento de onda ou polarização de luz diferente da dos seus vizinhos, funciona como uma correia transportadora óptico, o transporte de nanopartiCiclos mais de uma distância de alguns micra num chip. O chamado &#39;Nano-óptica Correia Transportadora&#39; (NOCB) é único entre os regimes de ressonador de armadilhagem plasmonic, como não só ele pode conter partículas no lugar, mas também pode movê-los em alta velocidade ao longo das trilhas estampados, reunir ou dispersar as partículas, misturar e fila-los, e até mesmo classificá-los por propriedades, tais como a sua mobilidade 23. Todas estas funções são controladas através da modulação do comprimento de onda ou polarização de iluminação, sem necessidade de óptica de orientação de feixe. Como uma armadilha óptica de campo próximo, o NOCB prendendo resolução é maior do que a de armadilhas ópticas de feixe focado convencionais, de modo que pode diferenciar entre as partículas em estreita proximidade; porque ele usa uma nanoestrutura metálica para concentrar a luz em um prendendo bem, é eficiente em termos de energia, e não requer componentes ópticos caros, como um objectivo elevado NA. Além disso, muitos NOCBs podem ser operados em paralelo, com alto embalagem densidade, no mesmo substrato, e um W de potência pode dirigir mais de 1200 aberturas 23. Temos demonstrado recentemente o primeiro NOCB-driven polarização, sem problemas impulsionando uma nanopartícula frente e para trás ao longo de uma faixa de 4,5 mm 24. Neste artigo apresentamos os passos necessários para projetar e fabricar o dispositivo, opticamente ativá-lo e reproduzir o experimento de transporte. Esperamos que a esta técnica mais amplamente disponível vai ajudar a preencher a lacuna entre a óptica tamanho microfluídica, em campo distante e dispositivos em nanoescala e 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

A técnica de utilização de feixes de laser focado para interceptar e exercem forças em pequenas partículas permitiu que muitas descobertas fundamentais nas ciências biológicas e físicas em nanoescala ao longo dos últimas décadas. Os progressos realizados neste domínio convida um estudo mais aprofundado dos sistemas ainda menores e em maior escala, com ferramentas que poderiam ser distribuídos com mais facilidade e fez mais amplamente disponível. Infelizmente, as leis fundamentais de difracção de limitar o tamanho mínimo do ponto focal de um feixe de laser, o que faz com que as partículas mais pequenas do que uma metade do comprimento de onda, em diâmetro difícil de armadilha e geralmente impede um operador de discriminar entre as partículas que estão mais próximos do que metade -Comprimento de onda. Isso impede a manipulação óptica de muitas nanopartículas estreitamente espaçados e limita a resolução de sistemas óptico-mecânicos. Além disso, utilizando feixes de manipulação óptica requer focalizados de formação de feixe ou de direcção, as quais podem ser muito volumoso e caro. Endereçarestas limitações na escalabilidade do sistema convencional de captura óptica nosso laboratório desenvolveu uma técnica alternativa que utiliza óptica de campo próximo para mover partículas através de um chip. Em vez de focar feixes de laser no campo distante, o campo próximo óptica de ressonadores plasmonic produz o reforço intensidade óptica local necessária para superar as restrições de difração e manipular partículas com maior resolução. Ressonadores de perto espaçadas produzir fortes armadilhas ópticas que podem ser abordados para mediar a mão-off de partículas a partir de um para o outro de uma forma-de tapetes transportadores semelhantes. Aqui, descrevemos como projetar e produzir uma correia transportadora com uma superfície de ouro modelado com plasmonic ressonadores em forma de C e como operá-lo com luz laser polarizada para atingir super-resolução manipulação de nanopartículas e transporte. O chip correia transportadora nano-óptico pode ser produzido usando técnicas de litografia e facilmente embalada e distribuída.

A Figura 7 é uma imagem do dispositivo final. No centro da superfície de ouro a 1 cm x 1 cm é a matriz de CSE e padrões de transporte, o que pode ser visto a partir de apenas uma vista angular. A Figura 6 é uma imagem de microscopia electrónica de varrimento de um exemplo de padrão de CSE no dispositivo final. O movimento de partículas de um poliestireno talão 390 nm viajar através de uma correia transportadora de nano-óptico de 5 um de compriment...

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.

Fabricação e operação de uma Correia 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 ...

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11.5K visualizações.  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.

Vídeo: 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.

Um método para fabricar nanoestruturas de prata desconectados em 3D

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

Engenharia

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.

Captura óptica de 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.

Fabricação de Nano-engenharia transparentes Óxidos Realização por deposição por laser 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.

Fabricação e Teste de microfluídicos optomechanical 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.

Atomicamente rastreável Fabrication Nanostructure

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.

Fabricação de 1-D cristal fotônico cavidade em um nanofibras com ablação induzida por laser 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.

Fabricação de nanoestruturas magnéticas nas membranas de nitreto de silício para estudos de vórtice magnético utilizando técnicas de microscopia de transmissão

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.

Construção e operação de um sistema de Motor controlado por luz ouro 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.

Projeto e fabricação de uma fibra óptica feito de água

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.

Fabricação de canais de nanoaltura incorporando atuação de onda acústica superficial via Niobate de lítio para nanofluidos acústicos

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