Jump to Content
View Cart
Top 20 Most Read Articles
February 2010
The 20 articles with the most full-text downloads during the month, in descending order.
 |
A portable high-field pulsed-magnet system for single-crystal x-ray scattering studies Rev. Sci. Instrum. 80, 113902 (2009); http://dx.doi.org/10.1063/1.3251273 (5 pages) Online Publication Date: 6 November 2009
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
We present a portable pulsed-magnet system for x-ray studies of materials in high magnetic fields (up to 30 T). The apparatus consists of a split-pair of minicoils cooled on a closed-cycle cryostat, which is used for x-ray diffraction studies with applied field normal to the scattering plane. A second independent closed-cycle cryostat is used for cooling the sample to near liquid helium temperatures. Pulsed magnetic fields ( ∼ 1 ms in total duration) are generated by discharging a configurable capacitor bank into the magnet coils. Time-resolved scattering data are collected using a combination of a fast single-photon counting detector, a multichannel scaler, and a high-resolution digital storage oscilloscope. The capabilities of this instrument are used to study a geometrically frustrated system revealing strong magnetostrictive effects in the spin-liquid state.
|
|||
|
Show PACS
|
|||
|
|
WSXM: A software for scanning probe microscopy and a tool for nanotechnology Rev. Sci. Instrum. 78, 013705 (2007); http://dx.doi.org/10.1063/1.2432410 (8 pages) Online Publication Date: 31 January 2007
Full Text:
Read Online (HTML)
|
Download PDF
|
|||
|
Show Abstract
In this work we briefly describe the most relevant features of WSXM, a freeware scanning probe microscopy software based on MS-Windows. The article is structured in three different sections: The introduction is a perspective on the importance of software on scanning probe microscopy. The second section is devoted to describe the general structure of the application; in this section the capabilities of WSXM to read third party files are stressed. Finally, a detailed discussion of some relevant procedures of the software is carried out.
|
||||
|
Show PACS
|
||||
|
|
Variable-wavelength frequency-domain terahertz ellipsometry Rev. Sci. Instrum. 81, 023101 (2010); http://dx.doi.org/10.1063/1.3297902 (7 pages) Online Publication Date: 2 February 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
We report an experimental setup for wavelength-tunable frequency-domain ellipsometric measurements in the terahertz spectral range from 0.2 to 1.5 THz employing a desktop-based backward wave oscillator source. The instrument allows for variable angles of incidence between 30° and 90° and operates in a polarizer-sample-rotating analyzer scheme. The backward wave oscillator source has a tunable base frequency of 107–177 GHz and is augmented with a set of Schottky diode frequency multipliers in order to extend the spectral range to 1.5 THz. We use an odd-bounce image rotation system in combination with a wire grid polarizer to prepare the input polarization state. A highly phosphorous-doped Si substrate serves as a first sample model system. We show that the ellipsometric data obtained with our novel terahertz ellipsometer can be well described within the classical Drude model, which at the same time is in perfect agreement with midinfrared ellipsometry data obtained from the same sample for comparison. The analysis of the terahertz ellipsometric data of a low phosphorous-doped n-type Si substrate demonstrates that ellipsometry in the terahertz spectral range allows the determination of free charge-carrier properties for electron concentrations as low as 8×1014 cm−3.
|
|||
|
Show PACS
|
|||
|
|
Rev. Sci. Instrum. 80, 125104 (2009); http://dx.doi.org/10.1063/1.3264082 (7 pages) Online Publication Date: 7 December 2009
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
An array of three identical piezoelectric microcantilever sensors (PEMSs) consisting of a lead zirconate titanate layer bonded to a glass layer was fabricated and examined for simultaneous, in situ, real-time, all-electrical detection of Bacillus anthracis (BA) spores in an aqueous suspension using the first longitudinal extension mode of resonance. With anti-BA antibody immobilized on the sensor surfaces all three PEMS exhibited identical BA detection resonance frequency shifts at all tested concentrations, 10–107 spores/ml with a standard deviation of less than 10%. The detection concentration limit of 10 spores/ml was about two orders of magnitude lower than would be permitted by flexural peaks. In blinded-sample testing, the array PEMS detected BA in three samples containing BA: (1) 3.3×103 spores/ml, (2) a mixture of 3.3×103 spores/ml and 3.3×105 S. aureus (SA) and P. aeruginosa (PA) per ml, and (3) a mixture of 3.3×103 spores/ml with 3.3×106 SA+PA/ml. There was no response to a sample containing only 3.3×106 SA+PA/ml. These results illustrate the sensitivity, specificity, reusability, and reliability of array PEMS for in situ, real-time detection of BA spores.
|
|||
|
Show PACS
|
|||
|
|
In situ manipulation of scanning tunneling microscope tips without tip holder Rev. Sci. Instrum. 81, 013706 (2010); http://dx.doi.org/10.1063/1.3284508 (5 pages) Online Publication Date: 25 January 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
|||
|
Show Abstract
A design for a manipulator system for manipulating bare scanning tunneling microscopy (STM) tips without any tip holder is presented. The extremely stiff and rigid system consists of an ultrahigh vacuum compatible fully three-dimensionally movable gripper module driven by stepping motors and piezomotors. The tips are clamped by hardened tool steel gripper jaws, which are controlled by a stepping motor through levers. The system allows the reproducible manipulation of bare tungsten tips made of wires with diameters of 0.25 nm and having length of only up to 3 mm without damaging the tip or the STM. The tip manipulators’ advantage is that the total mass of the scanning piezotube is reduced by removing the mass of a separate tip holder. Thereby, it becomes possible to further increase the resonance frequencies of the STM.
|
||||
|
Show PACS
|
||||
|
|
Note: A simple, convenient, and reliable method to prepare gold scanning tunneling microscope tips Rev. Sci. Instrum. 81, 016110 (2010); http://dx.doi.org/10.1063/1.3293459 (3 pages) Online Publication Date: 25 January 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
A simple method to prepare gold tips for scanning tunneling microscopy has been introduced. In this method, electrochemical etching without a hazardous electrolyte was employed. The setup uses basic laboratory instrumentation to control the etching process. This avoids purchasing complicated, expensive, and dedicated equipment for tip preparation. A procedure to optimize the etching parameters by setting the current limit is described. Etched tips were checked with both optical and scanning electron microscopy.
|
|||
|
Show PACS
|
|||
|
|
Femtosecond pulse shaping using spatial light modulators Rev. Sci. Instrum. 71, 1929 (2000); http://dx.doi.org/10.1063/1.1150614 (32 pages)
Full Text:
|
Download PDF
|
||
|
Show Abstract
We review the field of femtosecond pulse shaping, in which Fourier synthesis methods are used to generate nearly arbitrarily shaped ultrafast optical wave forms according to user specification. An emphasis is placed on programmable pulse shaping methods based on the use of spatial light modulators. After outlining the fundamental principles of pulse shaping, we then present a detailed discussion of pulse shaping using several different types of spatial light modulators. Finally, new research directions in pulse shaping, and applications of pulse shaping to optical communications, biomedical optical imaging, high power laser amplifiers, quantum control, and laser-electron beam interactions are reviewed. © 2000 American Institute of Physics. |
|||
|
Show PACS
|
|||
|
|
Rev. Sci. Instrum. 75, 2787 (2004); http://dx.doi.org/10.1063/1.1785844 (23 pages) Online Publication Date: 2 September 2004
Full Text:
|
Download PDF
|
||
|
Show Abstract
Since their invention just over 20 years ago, optical traps have emerged as a powerful tool with broad-reaching applications in biology and physics. Capabilities have evolved from simple manipulation to the application of calibrated forces on—and the measurement of nanometer-level displacements of—optically trapped objects. We review progress in the development of optical trapping apparatus, including instrument design considerations, position detection schemes and calibration techniques, with an emphasis on recent advances. We conclude with a brief summary of innovative optical trapping configurations and applications. |
|||
|
Show PACS
|
|||
|
|
Rev. Sci. Instrum. 81, 014301 (2010); http://dx.doi.org/10.1063/1.3277116 (7 pages) Online Publication Date: 19 January 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
We present a novel method for integrating two single-molecule measurement modalities, namely, total internal reflection microscopy and electrical detection of biomolecules using nanopores. Demonstrated here is the electrical measurement of nanopore based biosensing performed simultaneously and in-sync with optical detection of analytes. This method makes it possible, for the first time, to visualize DNA and DNA-protein complexes translocating through a nanopore with high temporal resolution (1000 frames/s) and good signal to background. This paper describes a detailed experimental design of custom optics and data acquisition hardware to achieve simultaneous high resolution electrical and optical measurements on labeled biomolecules as they traverse through a ∼ 4 nm synthetic pore. In conclusion, we discuss new directions and measurements, which this technique opens up.
|
|||
|
Show PACS
|
|||
|
|
Rev. Sci. Instrum. 81, 013101 (2010); http://dx.doi.org/10.1063/1.3276682 (9 pages) Online Publication Date: 4 January 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
A folded geometry acousto-optic modulator spatial pulse shaper has been designed for shaping individual pulses from a high power amplified laser. The design preserves the capability of computer programmable amplitude and phase modulation of femtosecond laser pulses. An additional application of genetic algorithm optimization approach for compressing a stretched pulse is also demonstrated for such a pulse shaper. Spectrally and temporally resolved optical gating technique is used to characterize the shaped pulses.
|
|||
|
Show PACS
|
|||
|
|
Rev. Sci. Instrum. 81, 023703 (2010); http://dx.doi.org/10.1063/1.3297901 (10 pages) Online Publication Date: 2 February 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
We have developed a low noise all-fiber interferometer for use as the deflection sensor in liquid environment frequency modulated atomic force microscopy (FM-AFM). A detailed description and rationale for the choice of the critical components are provided along with the design of a simple alignment assembly. The optimization of the deflection sensor toward achieving the highest possible sensitivity and lowest deflection noise density is discussed in the context of an ideal interference cavity. Based on the provided analysis we have achieved deflection noise densities of 2 fm/
 on commercially available cantilevers in both ambient and liquid environments. The low noise interferometer works without the need for differential detection, special focusing lenses, or polarization sensitive optics, dramatically simplifying measurements. True atomic resolution imaging of muscovite mica by FM-AFM in water is demonstrated using the developed deflection sensor. |
|||
|
Show PACS
|
|||
|
|
Calibration of atomic‐force microscope tips Rev. Sci. Instrum. 64, 1868 (1993); http://dx.doi.org/10.1063/1.1143970 (6 pages)
Full Text:
|
Download PDF
|
||
|
Show Abstract
Images and force measurements taken by an atomic‐force microscope (AFM) depend greatly on the properties of the spring and tip used to probe the sample’s surface. In this article, we describe a simple, nondestructive procedure for measuring the force constant, resonant frequency, and quality factor of an AFM cantilever spring and the effective radius of curvature of an AFM tip. Our procedure uses the AFM itself and does not require additional equipment. |
|||
|
Show PACS
|
|||
|
|
Multifunctional integrating sphere setup for luminous flux measurements of light emitting diodes Rev. Sci. Instrum. 81, 023102 (2010); http://dx.doi.org/10.1063/1.3285263 (7 pages) Online Publication Date: 2 February 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
A multifunctional setup based on the absolute integrating sphere method for measuring luminous flux of light emitting diodes (LEDs) is presented. The total luminous flux in 2π and 4π geometries and partial luminous flux with variable cone angle can be measured with the same custom-made integrating sphere. The number and area of ports and baffles of the sphere was minimized. The sphere has three ports: a main port, a detector port, and an auxiliary port, located in the same hemisphere. The other hemisphere is free of ports. The main port is used for the calibration of the sphere as well as for the LED under test. Only one absolute calibration of the integrating sphere photometer is needed for measuring LEDs in all three geometries. The spatial nonuniformity correction is needed only for LEDs with low directivity or having significant minor beams. The expanded uncertainty (k = 2) for the measurement setup varies between 1.2% and 4.6% depending on the measurement geometry, color, and the angular spread of the LED light beam. A complete calibration procedure of the constructed integrating sphere photometer is presented as well as comparison measurements with a goniophotometer.
|
|||
|
Show PACS
|
|||
|
|
Rev. Sci. Instrum. 80, 105105 (2009); http://dx.doi.org/10.1063/1.3249561 (8 pages) Online Publication Date: 28 October 2009
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
It is of practical importance to lead laboratory-scale experiments allowing a better understanding of the impact of commercial fuels composition on the formation of combustion residues such as soot particles. To this end, a hybrid burner has been designed recently to burn high-speed sprays of small liquid fuel droplets. It consists of a Holthuis (previously McKenna) burner originally equipped with a direct injection high efficiency nebulizer for the atomization of liquid hydrocarbons. A detailed description of this original setup is given in this paper. A priori estimations of atomization and evaporation times and length scales are then proposed and compared with experimental data. Droplet-size distribution measurements obtained in nonreacting conditions using a Malvern Spraytec particle sizer are presented and compared with values estimated by calculation. Cold sprays contours and liquid jet lengths in flames determined by Mie scattering at 532 and 1064 nm, respectively, are also presented. The results discussed in this work indicate that the hydrodynamic characteristics of the sprays generated with our system are relatively independent of the physical properties of fuels leading to comparable flames with identical liquid jet lengths, dimensions, and global structure. This feature facilitates an accurate comparison of flames burning various liquid hydrocarbons, which is of interest to emphasize differences in pollutants emissions and to highlight chemical effects for soot formation analysis.
|
|||
|
Show PACS
|
|||
|
|
Single crystal diamond tips for scanning probe microscopy Rev. Sci. Instrum. 81, 013703 (2010); http://dx.doi.org/10.1063/1.3280182 (4 pages) Online Publication Date: 14 January 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
|||||||||||||
|
Show Abstract
Single crystal diamond tips with perfect pyramidal geometry were obtained by a combination of chemical vapor deposition and selective oxidation of polycrystalline films. The parameters of the deposition process were chosen to provide growth of a textured film consisting of micrometer sized diamond crystallites embedded into nanodiamond ballas-like material. The heating of the film in an air environment was used for selective oxidation of the nanodiamond component. The films obtained contain free standing pyramidal single crystal diamond tips oriented by their apexes to the substrate surface. The tips were used for the fabrication of atomic force microscopy probes and their evaluation in comparison to common silicon probes.
|
||||||||||||||
|
Show PACS
|
||||||||||||||
|
|
A compact multipurpose nanomanipulator for use inside a scanning electron microscope Rev. Sci. Instrum. 81, 023704 (2010); http://dx.doi.org/10.1063/1.3271033 (4 pages) Online Publication Date: 5 February 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
A compact, two-stage nanomanipulator was designed and built for use inside a scanning electron microscope. It consists of a fine stage employing piezostacks that provide a 15 μm range in three dimensions and a coarse stage based on commercially available stick-slip motors. Besides the fabrication of enhanced probes for scanning probe microscopy and the enhancement of electron field emitters, other novel manipulation processes were developed, such as locating, picking up, and positioning small nanostructures with an accuracy of ∼ 10 nm. In combination with in situ I-V experiments, welding, and etching, this results in a multipurpose nanofactory, enabling a new range of experiments.
|
|||
|
Show PACS
|
|||
|
|
Rev. Sci. Instrum. 76, 061101 (2005); http://dx.doi.org/10.1063/1.1927327 (12 pages) Online Publication Date: 26 May 2005
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
Nanoelectromechanical systems (NEMS) are drawing interest from both technical and scientific communities. These are electromechanical systems, much like microelectromechanical systems, mostly operated in their resonant modes with dimensions in the deep submicron. In this size regime, they come with extremely high fundamental resonance frequencies, diminished active masses,and tolerable force constants; the quality (Q) factors of resonance are in the range Q ∼ 103–105—significantly higher than those of electrical resonant circuits. These attributes collectively make NEMS suitable for a multitude of technological applications such as ultrafast sensors, actuators, and signal processing components. Experimentally, NEMS are expected to open up investigations of phonon mediated mechanical processes and of the quantum behavior of mesoscopic mechanical systems. However, there still exist fundamental and technological challenges to NEMS optimization. In this review we shall provide a balanced introduction to NEMS by discussing the prospects and challenges in this rapidly developing field and outline an exciting emerging application, nanoelectromechanical mass detection.
|
|||
|
Show PACS
|
|||
|
|
Rev. Sci. Instrum. 80, 081101 (2009); http://dx.doi.org/10.1063/1.3184828 (23 pages) Online Publication Date: 5 August 2009
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
We review the current state of multiphoton microscopy. In particular, the requirements and limitations associated with high-speed multiphoton imaging are considered. A description of the different scanning technologies such as line scan, multifoci approaches, multidepth microscopy, and novel detection techniques is given. The main nonlinear optical contrast mechanisms employed in microscopy are reviewed, namely, multiphoton excitation fluorescence, second harmonic generation, and third harmonic generation. Techniques for optimizing these nonlinear mechanisms through a careful measurement of the spatial and temporal characteristics of the focal volume are discussed, and a brief summary of photobleaching effects is provided. Finally, we consider three new applications of multiphoton microscopy: nonlinear imaging in microfluidics as applied to chemical analysis and the use of two-photon absorption and self-phase modulation as contrast mechanisms applied to imaging problems in the medical sciences.
|
|||
|
Show PACS
|
|||
|
|
Machine vision for digital microfluidics Rev. Sci. Instrum. 81, 014302 (2010); http://dx.doi.org/10.1063/1.3274673 (7 pages) Online Publication Date: 22 January 2010
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
Machine vision is widely used in an industrial environment today. It can perform various tasks, such as inspecting and controlling production processes, that may require humanlike intelligence. The importance of imaging technology for biological research or medical diagnosis is greater than ever. For example, fluorescent reporter imaging enables scientists to study the dynamics of gene networks with high spatial and temporal resolution. Such high-throughput imaging is increasingly demanding the use of machine vision for real-time analysis and control. Digital microfluidics is a relatively new technology with expectations of becoming a true lab-on-a-chip platform. Utilizing digital microfluidics, only small amounts of biological samples are required and the experimental procedures can be automatically controlled. There is a strong need for the development of a digital microfluidics system integrated with machine vision for innovative biological research today. In this paper, we show how machine vision can be applied to digital microfluidics by demonstrating two applications: machine vision-based measurement of the kinetics of biomolecular interactions and machine vision-based droplet motion control. It is expected that digital microfluidics-based machine vision system will add intelligence and automation to high-throughput biological imaging in the future.
|
|||
|
Show PACS
|
|||
|
|
Photoacoustic imaging in biomedicine Rev. Sci. Instrum. 77, 041101 (2006); http://dx.doi.org/10.1063/1.2195024 (22 pages) Online Publication Date: 17 April 2006
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
Photoacoustic imaging (also called optoacoustic or thermoacoustic imaging) has the potential to image animal or human organs, such as the breast and the brain, with simultaneous high contrast and high spatial resolution. This article provides an overview of the rapidly expanding field of photoacoustic imaging for biomedical applications. Imaging techniques, including depth profiling in layered media, scanning tomography with focused ultrasonic transducers, image forming with an acoustic lens, and computed tomography with unfocused transducers, are introduced. Special emphasis is placed on computed tomography, including reconstruction algorithms, spatial resolution, and related recent experiments. Promising biomedical applications are discussed throughout the text, including (1) tomographic imaging of the skin and other superficial organs by laser-induced photoacoustic microscopy, which offers the critical advantages, over current high-resolution optical imaging modalities, of deeper imaging depth and higher absorption contrasts, (2) breast cancer detection by near-infrared light or radio-frequency–wave-induced photoacoustic imaging, which has important potential for early detection, and (3) small animal imaging by laser-induced photoacoustic imaging, which measures unique optical absorption contrasts related to important biochemical information and provides better resolution in deep tissues than optical imaging.
|
|||
|
Show PACS
|
|||
This Publication
Scitation
Google Scholar
PubMed