Using a simple method of direct heating bulk copper plates in air, oriented CuO nanowire films were synthesized on large scale. The length and density nanowires could be controlled by growth temperature time. Field emission (FE) measurements show that they have low turn-on field 3.5–4.5 V µm−1 current 0.45 mA cm−2 under an applied about 7 µm−1. By comparing the FE properties two types samples with different average lengths densities (30 µm, 108 4 × 107 cm−2, respectively), we found...

The video stream captured by an in-line holographic microscope can be analyzed on a frame-by-frame basis to track individual colloidal particles' three-dimensional motions with nanometer resolution. In this work, we compare the performance of two complementary analysis techniques, one based fitting exact Lorenz-Mie theory and other phenomenological interpretation scattered light field reconstructed Rayleigh-Sommerfeld back-propagation. Although tracking provides more information is...

We present a simple technique for manipulating and assembling one-dimensional (1D) CuO nanorods. Our exploits the optical trapping ability of line tweezers to trap, manipulate rotate nanorods without physical contact. With this versatile method, can be readily arranged into interesting configurations. The lin et weezers could also used an individual nanorod across two conducting electrodes. This work demonstrates potential manipulation assembly 1D nanostructures useful nanoelectronics...

The video stream captured by an in-line holographic microscope can be analyzed on a frame-by-frame basis to track individual colloidal particles' three-dimensional motions with nanometer resolution, and simultaneously measure their sizes refractive indexes. Through combination of hardware acceleration software optimization, this analysis carried out in near real time off-the-shelf instrumentation. An efficient particle identification algorithm automates initial position estimation sufficient...

The determination of optical force as a consequence momentum transfer is inevitably subject to the use proper density and stress tensor. It imperative valuable consider intrinsic scheme photon transfer, particularly when particle embedded in complex dielectric environment. Typically, we submerged an inhomogeneous background composed different materials, excluding coherent illumination or hydrodynamic effects. A ray-tracing method adopted capture direct process from medium, this approach...

Rayleigh-Sommerfeld back-propagation can be used to reconstruct the three-dimensional light field responsible for recorded intensity in an in-line hologram. Deconvolving volumetric reconstruction with optimal kernel derived from propagator itself emphasizes objects scattering pattern while suppressing both propagating and also such artifacts as twin image. Bright features deconvolved volume may identified colloidal spheres nanorods. Tracking their thermally-driven Brownian motion through...

We use holographic video microscopy to track the three-imensional translational and rotational diffusion of copper oxide nanorods suspended in water. Rayleigh-Sommerfeld back-propagation a single snapshot yields volumetric reconstruction nanorod's optical scattering pattern, from which we estimate both its dimensions also instantaneous position orientation. Analyzing sequence measurements freely diffusing dynamics, technique's resolution.

Abstract This paper investigates the singular optics of nonparaxial light beams in near field when behaves as a tractor beam. New insights into optical pulling force, which is usually represented by integrating stress tensor at black box enclosing object, are interpreted singularity Poynting vector. The negative nonconservative force originates from transfer azimuthal vector to longitudinal component partly owing presence scatterer. separatrice pattern and shifts unanimously exhibit...

A simple focused laser beam pruning method is used to fabricate unique two‐ and three‐ dimensional structures (see Figure the cover), without a pre‐patterned substrate under ambient conditions. The construction of microscopic movable carbon nanotube (CNT) that are controlled by light also reported. technique allows wide range 3D CNT microstructures be created.

We report a simple technique for the fabrication of two-dimensional periodic non-close-packed array nonspherical particles. The exploits self-assembly uniformly sized colloidal microspheres on surface Si substrate followed by reactive ion etching (RIE) that converts spheres into Single and double layers packed polystyrene uniform size (diameter 1.2 μm) were spin-coated onto cleaned substrates. samples then exposed to ions in an RIE unit operating under mixture CF4 O2 gases. Due preferential...

Holograms of colloidal spheres recorded through holographic video microscopy can be analyzed with the theory light scattering to measure individual spheres' sizes and refractive indexes part-per-thousand resolution. This information, in turn, interpreted estimate each sphere's porosity.

Determining the size distribution and composition of particles suspended in water can be challenging heterogeneous multicomponent samples. Light scattering techniques measure particle sizes, but provide no basis for distinguishing different types particles. Direct imaging categorize by shape, offer few insights into their composition. Holographic characterization meets this need directly measuring size, refractive index, three-dimensional position individual a suspension. The ability to an...

Abstract Chemical mechanical planarization (CMP) is a critical element in semiconductor manufacturing used to achieve the required nanometer-scale wafer surface planarity. Contaminants CMP polishing slurries can cause defects and reduce yield. Two contaminant sources are pad debris agglomerates of nanoparticles from slurries. Both these defects, be difficult distinguish. Reliable methods quantitatively measure identify contaminants during processing an ongoing challenge. This work introduces...

We report a simple and effective approach to organize micron- submicron-sized particles in size selective manner. This utilizes the template assisted directed self-assembly technique. A topographically patterned photoresist surface is fabricated used create an ordered array of colloidal from their aqueous suspensions. Assembly on this then achieved by using conventional spin coating Feasibility technique form large area particle assemblies has been investigated. To arrange template, physical...

Tracking fast-swimming bacteria in three dimensions can be extremely challenging with current optical techniques and a microscopic approach that rapidly acquire volumetric information is required. Here, we introduce phase-contrast holographic video microscopy as solution for the simultaneous tracking of multiple fast moving cells dimensions. This technique uses interference patterns formed between scattered incident field to infer three-dimensional (3D) position size bacteria. Using this...

In-line holographic microscopy images of micrometer-scale fractal aggregates can be interpreted with an effective-sphere model to obtain each aggregate's size and the population-averaged dimension. We demonstrate this technique experimentally using clusters polystyrene nanoparticles protein composed bovine serum albumin pancreas insulin.

The in-line hologram of a micrometer-scale colloidal sphere can be analyzed with the Lorenz-Mie theory light scattering to obtain precise measurements sphere's diameter and refractive index. same technique also used characterize porous irregularly shaped particles provided that extracted parameters are interpreted effective-medium represent properties an equivalent effective sphere. Here, we demonstrate effective-sphere model consistently accounts for changes in index medium as it fills...

The degradation of polysorbate surfactants can limit the shelf life biologic pharmaceutical products. Polysorbate is susceptible to via either oxidation or hydrolysis pathways which releases free fatty acids (FFA) and other complex polymers. Degradants from 80 (PS80) form particles impact drug product quality. PS80 products appear at low concentrations, their refractive indexes are similar that buffer, making them very challenging detect. Furthermore, aggregates FFA in size index protein...

Holographic particle characterization uses in-line holographic microscopy and the Lorenz-Mie theory of light scattering to measure diameter refractive index individual colloidal particles in their native dispersions. This wealth information has proved invaluable fields as diverse soft-matter physics, biopharmaceuticals, wastewater management, food science but so far been available only for dispersions transparent media. Here, we demonstrate that can yield precise accurate results even when...

Abstract Total holographic characterization (THC) is presented here as an efficient, automated, label-free method of accurately identifying cell viability. THC a single-particle technology that determines the size and index refraction individual particles using Lorenz–Mie theory light scattering. Although assessment viability challenge in many applications, including biologics manufacturing, traditional approaches often include unreliable labeling with dyes and/or time consuming methods...

We develop a simple to implement, inherently parallel and high throughput technique for the fabrication of large areas patterned aligned multi-wall carbon nanotube (CNT) arrays deposited on silicon or quartz substrate. This makes use converging laser beam from power pulsed destruction CNTs with copper grid as lithography mask define CNT arrays. The wavelength used is 248 nm average energy per pulse 500 mJ. Using this technique, an extensive area 3 × 5 mm2 can be fabricated without any...