Transmission microscopy without lenses for objects of unlimited size

Rodenburg, J. M.; Hurst, A C; Cullis, A. G.

doi:10.1016/j.ultramic.2006.07.007

Cited by 219 publications

(123 citation statements)

References 17 publications

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“…The potential of the method in indeed yielding almost diffraction-limited resolution without using lenses or other optical components was furthermore confirmed by recent experiments with visible laser light [2,15]. Additional results, shown here in Fig.…”

Section: (A) (B)supporting

confidence: 78%

“…In his pioneering work Hoppe describes how finite coherent illumination can be used to restore the phase information from the interference pattern recorded between the Bragg peaks of a crystalline specimen. The method was further developed for non-periodic objects [10][11][12], combined with iterative phase retrieval algorithms [13,14] and finally demonstrated with visible light and x-rays [1,2,15]. In the following, we briefly review the basic principles of the method and present some recent results obtained with x-rays and visible laser light.…”

Section: Ptychography and Coherent Diffractive Imagingmentioning

confidence: 99%

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Ptychography & lensless X-ray imaging

et al. 2008

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Section: (A) (B)supporting

confidence: 78%

Section: Ptychography and Coherent Diffractive Imagingmentioning

confidence: 99%

Ptychography & lensless X-ray imaging

et al. 2008

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“…This has the benefits of removing the stagnation problems that can occur for complex-valued object functions using conventional iterative methods, greatly speeding up convergence to the solution of the phase problem and allowing objects of unlimited size to be imaged. The technique has previously shown excellent results using both visible light 25 and hard X-rays. 26,27 We show that electron ptychography of largescale ͑200 nm͒ features can measure phase changes with about the same accuracy as off-axis holography but without the need for a stable reference wave and an area of free space adjacent to the area of interest.…”

Section: ͒mentioning

confidence: 99%

Wave-front phase retrieval in transmission electron microscopy via ptychography

et al. 2010

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There are many different strategies that allow the solving of the well-known phase problem corresponding to the loss of phase information during a physical measurement. In microscopy, and, in particular, in transmission electron microscopy, most of these strategies focus on the retrieval of high-resolution information with the importance of lower resolution data often overlooked. Ptychography offers a means to investigate such data. Ptychography is a robust diffractive imaging technique with fast convergence for phase retrieval but, until now, has not been applied at the nanoscale. In this paper, we use the ptychographical iterative engine to retrieve the phase change at the exit plane of metallic nanoparticles using a conventional transmission electron microscope. Ptychographical reconstructions yielded images with a phase resolution of / 10 and a spatial resolution of 1 nm. These results stand as a first step toward aberration-free lensless imaging. The technique lends itself to be an alternative to off-axis electron holography or focal series reconstruction. A very long-standing issue in transmission electron microscopy ͑TEM͒ has been how to measure accurately the phase of the electron wave emanating from the exit surface of the specimen. Because the wavelength of an electron is reduced as it passes through a potential well, the atomic potentials within the specimen can induce significant changes in its phase relative to its free-space propagation. Measurement of the induced phase change at the atomic scale or nanoscale has many important applications: for example, the measurement of the mean inner potential in materials ͑which depends upon the local chemical distribution 1 ͒, the measurement of magnetic fields around nanostructures, 2 or the measurement of internal electric fields within the specimen ͑e.g., at semiconductor junctions 3 ͒.Traditional TEM phase contrast is based upon an approximate version of Zernike's method 4 for thin and weakly scattering specimen. In essence, an interference image is created by adding the unscattered and phase-modified scattered terms. The resulting contrast is then a combination of amplitude and phase components. The transfer function of the lens is a serious limitation of this method, especially at low scattering angles ͑low-resolution components in the image͒, meaning that phase contrast works well only for relatively small-scale features, below about 1.0 nm. Furthermore, the weak-scattering approximation breaks down for all but the thinnest ͑few nanometers͒, light-element specimens.One technique that overcomes some of these limitations requires the recording of two or more images at different defoci of the objective lens, thus imaging a number of planes downstream of the object. As a wave propagates, only one phase distribution will be consistent with the measured changes of intensity. There are several methods for retrieving phase using such data. 5-8 However, because the wave intensity relies on local interference between wavelets in the Fresnel propagation integral,...

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“…An important advantage of this approach over conventional microscopy is that it can surpass the resolution limit imposed by lens imaging. In fact, it can work without any lenses at all 5 .…”

Section: J O H N R O D E N B U R Gmentioning

confidence: 99%

“…The cells that generate coronary arteries originate from various regions of the embryo, including a sac-like structure called the sinus venosus that adjoins the embryonic heart 5,6 . From these sites, the cells invade the heart's muscle-cell layer.…”

Section: John Rodenburg Is In the Departmentmentioning

confidence: 99%

A record-breaking microscope

Rodenburg¹

2018

Nature

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Transmission microscopy without lenses for objects of unlimited size

Cited by 219 publications

References 17 publications

Ptychography & lensless X-ray imaging

Ptychography & lensless X-ray imaging

Wave-front phase retrieval in transmission electron microscopy via ptychography

A record-breaking microscope

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