Name: fabrication and operation of a nano-optical conveyor belt
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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.

The NOCB combines the strong trapping forces and small trap size of plasmonic approaches with the capability to transport particles, long available only for conventional focused-beam techniques. Unique to the NOCB, the trapping and transport properties of the system are a result of surface patterning and not of shaping the illumination beam. Provided the illumination is bright enough and its polarization or wavelength can be modulated, particles can be held or moved in complicated protocols on the surface. We have demonstrated through simulation that an NOCB can also rapidly sort particles based on their mobility23. Near-field traps can serve as small reaction volumes for single-molecule chemistry, and the inherent parallelizability of the NOCB means it can be used to set up, perform and tear down as many simultaneous experiments as can be packed onto a chip and illuminated at once.
To get the NOCB to work, the near-field optical forces that hold and hand off nanoparticles must overcome the competing forces of viscous drag, conventional optical trapping (the force of the illumination beam), thermophoresis, and contact forces with other particles and the substrate itself. The near-field optical force should be as strong as possible for a given illumination power; this requires careful nanostructure design and fabrication, but in practice we need to produce a range of structures with different characteristic sizes to select the one that works the best for the given illumination wavelength. The viscous drag and thermophoresis must be suppressed as well: while they may not be able to pull particles out of near-field optical traps, they can certainly make it difficult to get a particle onto the NOCB array in the first place.
When the sample is first placed under the microscope, particles will distribute evenly throughout the volume and very rarely come near to the CSE array. (Calculations indicate that a particle must move within a few tens of nanometers of surface contact to be trapped.) When the illumination is initially turned on, the CSE array will immediately heat up and create a thermal gradient in the water that repels particles over a distance of several hundred nanometers. This barrier is overcome by trapping a particle at a distance with the focused illumination beam, and manually dragging the particle through the thermal barrier into the trapping field of the CSE. However even this method will fail if the thermal gradient is too high. In our experience, the inclusion of the copper heat sink layer was crucial for drawing the heat away from the water and weakening the thermal forces. The copper heat sink also makes it less likely that the water will boil under normal illumination intensity.
The optical gradient force on a very small particle scales as the cube of the particle diameter. This makes it much harder to trap a 100 nm bead than a 200 nm bead, since the power must be increased eight times&#8212;increasing the substrate heating by the same amount. As a practical matter we recommend trapping larger beads first (400 nm or 500 nm diameter), optimizing the trap strength and minimizing competing forces, and then attempting trapping and transport of smaller particles.
Once the sample has been prepared, experiments can be performed as long as the particles are freely floating in water. Water exits the sample by evaporation along the edges. In our lab this puts a roughly 20 min&#160;time limit on experiments. Evaporation can also result in a competing viscous drag force as water is drawn to the edges of the sample. If the sample has rough features such as bent-up metal edges or spikes that prevent it from lying flat on the glass slide, the greater exposed surface area of the water will speed evaporation. If one side is higher than the other, the evaporation will be biased towards the side with the larger sample-slide gap and the fluid will move rapidly over the nanostructures, making it harder to see, capture and hold particles.
A single NOCB can transport particles across the width of the illumination beam but no further. As the beam intensity drops off, the restoring force from the focused beam grows stronger and the NOCB handoff force grows weaker, until polarization rotation is more likely to release the particle than move it forward. For extension to longer conveyors or more parallel conveyors, the illumination area must be increased. A powerful, defocused laser diode could power a much larger area than the laser used in these experiments. Alternatively the illumination area can be increased by rapidly scanning the beam using an acousto-optic deflector.

捕获，审讯和操纵单个纳米颗粒在纳米技术越来越重要。光学镊子已成为在那里他们已启用突破实验如单DNA分子4和机械性能的测定在分子生物学1-4，化学5-7和纳米组装7-10，实验一特别成功操作技术细胞通过它们的光学性质11,12排序。这些前沿的发现开辟了更小的系统研究，他们让路新切实有益的产品和技术工程。反过来，这种趋势驱动需要新的技术来操纵更小，更基本的粒子。此外，还有一个推构建&#39;上实验室一个芯片的设备中，以便使化学和生物学检验出的更便宜和更小的封装执行这些功能实验室和进入该领域的医疗和其他目的13,14。 不幸的是，传统的光学捕获（COT）不能满足所有的纳米技术的日益增长的需求。 COT操作上使用高数值孔径（NA）的物镜，使激光光到紧聚焦，产生在光强度和高梯度的电磁场能量的局部峰值的机制。这些能量密度梯度施加的光漫射粒子的净力通常吸引他们在朝向焦点的中心。捕获更小的颗粒要求更高的光功率或突出重点。然而，光的聚焦光束服从衍射原理，这限制了焦斑的最小尺寸和在能量密度梯度了一个上限。有效的COT不能捕获的小物件，和COT有麻烦了密集的颗粒之间进行区分，一个诱捕分辨率:这有两个直接后果限制被称为"胖手指"的问题。此外，实现多个粒子捕获用COT需要光束转向光学器件或空间光调制器，组分急剧增加的光学捕获系统的成本和复杂性的系统。 规避光的常规聚焦光束的根本局限性的一种方法，所述传播在远场，是改为利用光的电磁能量的梯度，在近场。近场呈指数衰减远离电磁场源，这意味着不仅是它高度局部化到这些源，但它也表现出非常高的梯度在其能量密度。纳米金属谐振器，如蝴蝶结孔，纳米柱，和C形雕刻的近场，已被证明表现出近INFR非凡浓度的电磁能量，通过金，银的等离子体激元的作用的进一步增强的ARED和光的波长。这些谐振器已被用于捕集非常小的微粒子以高效率和分辨率15-22。虽然这一技术已被证明在捕集小颗粒有效的，它也被证明在其上可感知的范围，这是必要的，如果近场的系统与远场的系统或微流体接口输送粒子的能力是有限的。 最近，我们的组提出了解决这一问题。当谐振器被放置得很近，颗粒原则上可以从一个近场光阱到下迁移，而从表面释放。传输的方向可以，如果相邻的陷阱可打开和关闭分别确定。的三个或更多个可寻址的谐振器，其中每一个谐振器是一个偏振或光不同波长从它的邻居敏感的线性阵列，为光输送带，输送nanoparti克莱斯超​​过一个芯片上的距离为几微米。 所谓"纳米光传送带"（NOCB）是其中等离子谐振器诱捕方案独一无二的，因为它不仅可以在地方举办的颗粒，但它也可以沿着图案的轨道移动在高速，聚集或分散颗粒，混合排队它们，甚至对它们进行排序按性质，如他们的流动性23。所有这些功能都通过调制照明的偏振或波长，而无需光束转向光学器件的控制。作为近场光学陷阱，该NOCB诱捕分辨率比常规聚焦光束的光阱的更高，因此它可以在靠近颗粒之间区分;因为它采用了金属纳米结构，以光集中于一个俘获很好，这是功率效率，并且不需要昂贵的光学组件，例如一个高NA物镜。此外，许多NOCBs可以并行地操作时，在高的填充巢穴sity，在同一基板上，并且功率为1W可以驱动超过1200孔23。 我们最近展示了第一个偏振驱动NOCB，顺利推进纳米粒子来回沿着4.5微米的轨道24。在这篇文章中，我们提出必要的设计和制造设备的步骤，光激活并繁殖运输试验。我们希望使这一技术更广泛的应用将有助于弥补微流控，远场光学和纳米器件与实验之间的大小差距。

<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

使用聚焦激光束捕获并施加力的小颗粒的技术已使纳米生物和物理科学许多关键性的发现，在过去的几十年。在这一领域所取得的进展的邀请甚至较小的系统，并在更大的规模进一步的研究中，有可能更容易地分布并使其更广泛使用的工具。不幸的是，衍射的基本定律限制的激光束，这使得颗粒比半波长更小的直径难以捕集的焦斑的最小尺寸并且通常阻止操作者从颗粒之间鉴别它们是更靠近在一起超过一个半1/4波长。这就排除许多紧密排列的纳米粒子的光学操纵，并限制光学机械系统的​​分辨率。此外，操纵使用聚焦光束需要的波束形成或转向光学器件，它可以是非常笨重和昂贵。讲话在常规的光学捕获我们实验室的系统的可扩展这些限制已经设计出一种替代技术，其利用近场光学器件以跨越一个芯片移动的颗粒。代替聚焦激光束在远场的，电浆谐振器的光学近场产生必要的局部光强度增强，以克服衍射的限制，并在更高分辨率操作的颗粒。紧密间隔的谐振器产生可以加以处理以介导从一个越区切换粒子到下一个传送带状方式强烈光阱。在这里，我们将介绍如何设计和使用金表面图案与等离子C形谐振器和如何与偏振激光来实现超分辨率纳米操纵和运输操作它产生的传送带。纳米光输送带芯片可以使用光刻技术来制造，并容易包装和分发。

Figure 7 is a picture of the final device. At the center of the 1 cm x 1 cm gold surface is the matrix of CSE and conveyor patterns, which can be barely seen from an angled view. Figure 6 is a scanning electron microscopy image of an example CSE pattern on the final device.
The particle motion of a 390 nm polystyrene bead traveling across a nano-optical conveyor belt 5 &#181;m in length is shown in Figure 9. The curve shows the particle&#8217;s position as a function of laser polarization angle. As mentioned in the protocol, there may be cases where transport does not succeed or near-field trapping does not initiate. The best course of action is to try a different pattern, which may be in better condition.
<img alt="Figure 6" src="/files/ftp_upload/52842/52842fig6.jpg" /> 
Figure 6.&#160;SEM image of CSE Array. Scanning electron microscope (SEM) images of the CSE patterns. (a) shows the picture of HSQ mesas after the resist development. The sample is sputtered with 5 nm gold as a conducting layer for SEM inspection. (b)-(c) show final patterns after the sample is released from the silicon substrate. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/52842/52842fig6large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 7" src="/files/ftp_upload/52842/52842fig7.jpg" /> 
Figure 7.&#160;CSE Array Chip. Picture of the final device, roughly 10 mm x 10 mm in dimension. The picture shows the front gold surface of the device. Diffraction from grating ID markings is visible as multi-color squares near the center of the chip. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/52842/52842fig7large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 8" src="/files/ftp_upload/52842/52842fig8.jpg" /> 
Figure 8.&#160;Experimental apparatus. Schematic of the experimental apparatus. Both trapping and imaging are performed in reflection mode. The different light paths are distinguished using different colors. The red, green, dashed red, blue and yellow lines represent the light paths of optical trapping (conveyor driving), fluorescent imaging, laser imaging, fluorescent excitation and bright field illumination respectively. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/52842/52842fig8large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 9" src="/files/ftp_upload/52842/52842fig9.jpg" /> 
Figure 9.&#160;Bead Trajectory Over Double-Rail Conveyor. Position vs. polarization angle for a 390 nm bead moving on a 4.5 &#181;m long double-rail conveyor belt. Images on the left show snapshots of the sphere after each conveyor period. The curve on the right traces the calculated position of the bead centers. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/52842/52842fig9large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

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.

一个纳米光输送带的制作和操作

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

Nanyang Technological University

Research

Education

JoVE Core

JoVE Journal

Physics

Engineering

Unit 1

Electromagnetic Waves

SCIENTISTS IN ACTION

11.5K 次观看.  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.

视频: 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.

一个断开连接的银纳米结构的方法来制作的3D

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

科研

工程学

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.

纳米粒子的光学捕获

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.

制备纳米设计的脉冲激光沉积透明导电氧化物

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.

制造和微流控光机振荡器测试

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.

原子纳米结构可追溯制造

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.

1-D光子晶体空穴对纳米纤维使用飞秒激光诱导消融制造

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.

用透射显微技术制备氮化硅薄膜磁性纳米结构的研究

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.

轻型金纳米旋转电机系统的施工与运行

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.

一种水上光纤的设计与制造

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.

通过用于声学纳米流体的尼奥布精锂结合表面声波驱动纳米高通道的制造

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