Interface Characterisation Using an SEM-Based Micro-Indentor

1994 ◽  
Vol 365 ◽  
Author(s):  
M.H. Lewis ◽  
A.M. Daniel ◽  
M.G. Cain
Keyword(s):  
High Resolution ◽  
Interfacial Property ◽  
Shear Stresses ◽  
High Resolution Imaging ◽  
Displacement Monitoring ◽  
Wide Range ◽  
Resolution Imaging ◽  
Load Displacement ◽  
And Performance

ABSTRACTThe design and performance of an SEM-based microindentor, for interfacial property measurements in CMCs, is described. It enables high resolution imaging and simultaneous load/displacement monitoring with capacity and resolution of 20N ± lmN (load) and 100μm ± 10nm (displacement). Its application to measurement of interface debond and shear stresses for a wide range of fibres and monofilaments is described.

scholarly journals Introduction to the Joint Commission Meeting on High Resolution Imaging from the Ground

1989 ◽  
Vol 8 ◽  
pp. 545-546
Author(s):  
John Davis
Keyword(s):  
High Resolution ◽  
Angular Resolution ◽  
High Angular Resolution ◽  
High Resolution Imaging ◽  
Wide Range ◽  
High Resolution Images ◽  
Resolution Imaging ◽  
Optical Wavelengths ◽  
To Come ◽  
Very High

As a result of advances in instrumentation and techniques, from radio through to optical wavelengths, we have before us the prospect of producing very high resolution images of a wide range of objects across this entire spectral range. This prospect, and the new knowledge and discoveries that may be anticipated from it, lie behind an upsurge in interest in high resolution imaging from the ground. Several new high angular resolution instruments for radio, infrared, and optical wavelengths are expected to come into operation before the 1991 IAU General Assembly.

Progress in design, nanofabrication and performance of metalenses

2021 ◽  
Author(s):  
Zhenghao WANG ◽  
Yongling WU ◽  
Dongfeng QI ◽  
Wenhui YU ◽  
Hongyu ZHENG
Keyword(s):  
High Resolution ◽  
Near Infrared ◽  
Visible Range ◽  
Infrared Range ◽  
High Dispersion ◽  
High Resolution Imaging ◽  
Direct Writing ◽  
Nanoscale Structures ◽  
Resolution Imaging ◽  
And Performance

Abstract Metalens has been shown to overcome the diffraction limit of conventional optical lenses to achieve sub-wavelength resolution. Due to its planar structure and lightweight, metalens has the potential applications in the manufacture of flat lenses for cameras and other high resolution imaging optics. However, currently reported metalenses have low focusing efficiencies: 26% - 68% in THz and GHz range, 1% - 91% in near infrared range (NIR), and 5% - 91.6% in the visible range. Far field imaging in the visible light is essential for use in camera and mobile phones, which requires a complex metalens structure with multi-layers of alternating metal and dielectric layers. Most of the reported metalenses work in a single wavelength, mainly due to the high dispersion characteristics of the diffractive metalenses. It remains a challenge to realize high resolution imaging for a wide wavelength band in particular in the visible range. In this review, we report the state-of-the-art in metalens design principle, types of nanoscale structures, and various fabrication processes. We introduce femtosecond laser direct writing based on two-photon polymerization as an emerging nanofabrication technology. We provide an overview of the optical performance of the recently-reported metalenses and elaborate the major research and engineering challenges and future prospects.

Microcantilever-Based Force Tracking With Applications to High-Resolution Imaging and Nanomanipulation

2008 ◽  
Author(s):  
Reza Saeidpourazar ◽  
Nader Jalili
Keyword(s):  
High Resolution ◽  
Force Sensor ◽  
High Resolution Imaging ◽  
Mems Devices ◽  
Modeling Framework ◽  
Sensing Platforms ◽  
Force Tracking ◽  
Resolution Imaging ◽  
And Performance ◽  
Mass Spring

This paper presents the development and implementation of a robust nonlinear control framework for piezoresistive nanomechanical cantilever (NMC)-based force tracking with applications to high-resolution imaging and nanomanipulation. Among varieties of nanoscale force sensing platforms, NMC is an attractive approach to measure and apply forces at this scale when compared with other previously reported configurations utilizing complicated MEMS devices or inconvenient-to-handle nanowires and nanotubes. More specifically, a piezoresistive layer is utilized here to measure nanoscale forces at the NMC’s tip instead of bulky laser-based feedback which is commonly used in Atomic Force Microscopy (AFM). In order to track a predefined force trajectory at the NMC’s tip, there is a need to model the piezoresistive NMC and design appropriate controller to move its base to provide the desired force. In previous publications of the authors, a new distributed-parameters modeling framework has been proposed to precisely predict the force acting on the microcantilever’s tip. In contrast to this approach and in an effort to ease the follow-up controller development, the NMC-based force sensor is modeled here as a lumped-parameters system. However, replacing the NMC with a linear mass-spring-damper trio, creates a variety of uncertainties and unmodeled dynamics that need to be addressed for a precise force sensor’s read-out. Moreover, the very slow response of NMC’s piezoresistive layer to force variations at the NMC’s tip, makes the tracking problem even more challenging. For this, a new controller is proposed to overcome these roadblocks. Using extensive numerical simulations and experimental results it is shown that utilizing the proposed controller instead of the commonly used PID controller can significantly enhance the controller’s stability and performance characteristics, and ultimately the imaging resolution and manipulation accuracy needed at this scale.

A New 200kv Energy Filter Field Emission Transmission Electron Microscope

1998 ◽  
Vol 4 (S2) ◽  
pp. 396-397
Author(s):  
T. Kaneyama ◽  
K. Tsuno ◽  
T. Honda ◽  
M. Kersker ◽  
K. Tsuda ◽  
...  
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Field Emission ◽  
Transmission Electron Microscope ◽  
High Resolution Imaging ◽  
Elemental Mapping ◽  
Lens System ◽  
Transmission Electron ◽  
Wide Range ◽  
Resolution Imaging

In the field of biological and materials sciences, the importance of energy filter transmission electron microscope(EF-TEM) is increasing. Because it is a powerful instrument for contrast enhancement and obtaining elemental mapping images. We have developed a 200kV EF-TEM equipped with a fieldemission gun and in-column spectrometer. The new EF-TEM JEM-2010FEF inherits the performance in high resolution imaging and analysis from field emission TEM. The outer view is shown in Fig.l.Figure 2 shows the lens configuration of JEM-2010FEF. An in-column Q-type spectrometer is introduced within the imaging lens system. It was designed to have image distortion less than 1% and dispersion power 1.2p.m/eV for 200keV electrons. There is no need of compensating procedure of distortion. Imaging lens system consists of two objective lenses, three intermediate lenses and three projector lenses. The 8-stage imaging lens system enables wide range of imaging modes equal to conventional TEMs; energy spectroscopic image of magnification from ×200 to × 1,500,000, energy spectroscopic diffraction of camera length from 200mm to 2,000mm.

Alternative approaches to ultra-high resolution imaging

1991 ◽  
Vol 49 ◽  
pp. 650-651
Author(s):  
J.M. Cowley
Keyword(s):  
High Resolution ◽  
High Voltage ◽  
High Resolution Electron Microscopy ◽  
Crystal Defects ◽  
High Resolution Imaging ◽  
General Applicability ◽  
Resolution Electron ◽  
Radiation Resistant ◽  
Resolution Imaging ◽  
Alternative Approaches

By extrapolation of past experience, it would seem that the future of ultra-high resolution electron microscopy rests with the advances of electron optical engineering that are improving the instrumental stability of high voltage microscopes to achieve the theoretical resolutions of 1Å or better at 1MeV or higher energies. While these high voltage instruments will undoubtedly produce valuable results on chosen specimens, their general applicability has been questioned on the basis of the excessive radiation damage effects which may significantly modify the detailed structures of crystal defects within even the most radiation resistant materials in a period of a few seconds. Other considerations such as those of cost and convenience of use add to the inducement to consider seriously the possibilities for alternative approaches to the achievement of comparable resolutions.

Principle and practice of high-resolution imaging with a field-emission TEM

1992 ◽  
Vol 50 (1) ◽  
pp. 138-139
Author(s):  
Max T. Otten ◽  
Wim M.J. Coene
Keyword(s):  
High Resolution ◽  
Field Emission ◽  
Incidence Angle ◽  
Temporal Coherence ◽  
Energy Spread ◽  
High Resolution Imaging ◽  
Major Improvement ◽  
High Resolution Images ◽  
Resolution Imaging

High-resolution imaging with a LaB6 instrument is limited by the spatial and temporal coherence, with little contrast remaining beyond the point resolution. A Field Emission Gun (FEG) reduces the incidence angle by a factor 5 to 10 and the energy spread by 2 to 3. Since the incidence angle is the dominant limitation for LaB6 the FEG provides a major improvement in contrast transfer, reducing the information limit to roughly one half of the point resolution. The strong improvement, predicted from high-resolution theory, can be seen readily in diffractograms (Fig. 1) and high-resolution images (Fig. 2). Even if the information in the image is limited deliberately to the point resolution by using an objective aperture, the improved contrast transfer close to the point resolution (Fig. 1) is already worthwhile.

Imaging of ferroelectric domain walls by electron holography

1992 ◽  
Vol 50 (1) ◽  
pp. 246-247
Author(s):  
Xiao Zhang
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Domain Walls ◽  
Ferroelectric Domain ◽  
Object Wave ◽  
Electron Holography ◽  
High Resolution Imaging ◽  
Quantitative Measurements ◽  
Resolution Imaging ◽  
Electron Microscopes

Electron holography has recently been available to modern electron microscopy labs with the development of field emission electron microscopes. The unique advantage of recording both amplitude and phase of the object wave makes electron holography a effective tool to study electron optical phase objects. The visibility of the phase shifts of the object wave makes it possible to directly image the distributions of an electric or a magnetic field at high resolution. This work presents preliminary results of first high resolution imaging of ferroelectric domain walls by electron holography in BaTiO3 and quantitative measurements of electrostatic field distribution across domain walls.

The method of replication affects metal film granularity and resolution

1989 ◽  
Vol 47 ◽  
pp. 708-709
Author(s):  
George C. Ruben
Keyword(s):  
Electron Beam ◽  
High Resolution ◽  
Film Thickness ◽  
Single Molecule ◽  
Metal Film ◽  
Vertical Surface ◽  
High Resolution Imaging ◽  
Controllable Factors ◽  
Resolution Imaging

Single molecule resolution in electron beam sensitive, uncoated, noncrystalline materials has been impossible except in thin Pt-C replicas ≤ 150Å) which are resistant to the electron beam destruction. Previously the granularity of metal film replicas limited their resolution to ≥ 20Å. This paper demonstrates that Pt-C film granularity and resolution are a function of the method of replication and other controllable factors. Low angle 20° rotary , 45° unidirectional and vertical 9.7±1 Å Pt-C films deposited on mica under the same conditions were compared in Fig. 1. Vertical replication had a 5A granularity (Fig. 1c), the highest resolution (table), and coated the whole surface. 45° replication had a 9Å granulartiy (Fig. 1b), a slightly poorer resolution (table) and did not coat the whole surface. 20° rotary replication was unsuitable for high resolution imaging with 20-25Å granularity (Fig. 1a) and resolution 2-3 times poorer (table). Resolution is defined here as the greatest distance for which the metal coat on two opposing faces just grow together, that is, two times the apparent film thickness on a single vertical surface.

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