Observation of the Talbot effect using broadband hard x-ray beam

Kim, Jae‐Myung; Cho, In Hwa; Lee, Su Yong; Kang, Hyon Chol; Conley, Ray; Liu, Chian; Macrander, Albert T.; Noh, Do Young

doi:10.1364/oe.18.024975

Cited by 25 publications

(15 citation statements)

References 11 publications

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“…17 The multilayer array design extends the idea of Kim et al using a multilayer stack as a transmission grating 18 and allows us to realize very small grating periods over areas of several centimeters through a thin film deposition process. The grating design and fabrication method has been described in detail previously.…”

Section: Design Fabrication and Characterization Of Gratingsmentioning

confidence: 86%

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Interferometric hard x-ray phase contrast imaging at 204 nm grating period

Wen

Wolfe

Gomella

et al. 2013

Review of Scientific Instruments

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We report on hard x-ray phase contrast imaging experiments using a grating interferometer of approximately 1/10th the grating period achieved in previous studies. We designed the gratings as a staircase array of multilayer stacks which are fabricated in a single thin film deposition process. We performed the experiments at 19 keV x-ray energy and 0.8 μm pixel resolution. The small grating period resulted in clear separation of different diffraction orders and multiple images on the detector. A slitted beam was used to remove overlap of the images from the different diffraction orders. The phase contrast images showed detailed features as small as 10 μm, and demonstrated the feasibility of high resolution x-ray phase contrast imaging with nanometer scale gratings.

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Section: Design Fabrication and Characterization Of Gratingsmentioning

confidence: 86%

“…The method is modified from that described by Kim et al 18 and will be reported in detail in a separate manuscript. Briefly, a custom high resolution radiography film was placed in contact with the grating, which was exposed to the transmitted x-ray beam.…”

Section: Design Fabrication and Characterization Of Gratingsmentioning

confidence: 99%

Interferometric hard x-ray phase contrast imaging at 204 nm grating period

Wen

Wolfe

Gomella

et al. 2013

Review of Scientific Instruments

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“…The contact radiography was based on the method developed by Spiller and co-authors for x-ray microscopy[26, 36] with one modification. We coated <100> silicon wafers with the electron beam resist ZEP520A (Zeon Corporation) to be used as x-ray film plates.…”

Section: Methodsmentioning

confidence: 99%

“…The layers can be several nanometers thick and millimeters wide, and therefore as a transmission grating the depth-to-period ratio can be very high. Kim and co-authors successfully produced Talbot fringes of 0.39 μm period using a multilayer stack in a broadband synchrotron beam centered at 10 keV[26]. However, the limited height of a multilayer stack (< 50 μm)[27] precludes full-field imaging of large samples.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of 200 nm period centimeter area hard x-ray absorption gratings by multilayer deposition

Lynch

Liu

Morgan

et al. 2012

J. Micromech. Microeng.

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We describe the design and fabrication trials of x-ray absorption gratings of 200 nm period and up to 100:1 depth-to-period ratios for full-field hard x-ray imaging applications. Hard x-ray phase-contrast imaging relies on gratings of ultra-small periods and sufficient depth to achieve high sensitivity. Current grating designs utilize lithographic processes to produce periodic vertical structures, where grating periods below 2.0 μm are difficult due to the extreme aspect ratios of the structures. In our design, multiple bilayers of x-ray transparent and opaque materials are deposited on a staircase substrate, and mostly on the floor surfaces of the steps only. When illuminated by an x-ray beam horizontally, the multilayer stack on each step functions as a micro-grating whose grating period is the thickness of a bilayer. The array of micro-gratings over the length of the staircase works as a single grating over a large area when continuity conditions are met. Since the layers can be nanometers thick and many microns wide, this design allows sub-micron grating periods and sufficient grating depth to modulate hard x-rays. We present the details of the fabrication process and diffraction profiles and contact radiography images showing successful intensity modulation of a 25 keV x-ray beam.

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“…We developed a multi-layer array design for the 200 nm period diffraction gratings in the 17.5-25 keV energy range [15]. The design extends the idea of Kim and co-authors that a multi-layer stack works as a transmission grating in the lateral direction [16]. It consists of a silicon substrate in the shape of a staircase, onto which alternating layers of light (silicon) and heavy (tungsten) materials are deposited directionally onto the stair floors.…”

Section: Grating Design and Fabricationmentioning

confidence: 96%

Boosting phase contrast with a grating Bonse–Hart interferometer of 200 nanometre grating period

Wen

Gomella

Patel

et al. 2014

Phil. Trans. R. Soc. A.

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We report on a grating Bonse–Hart interferometer for phase-contrast imaging with hard X-rays. The method overcomes limitations in the level of sensitivity that can be achieved with the well-known Talbot grating interferometer, and without the stringent spectral filtering at any given incident angle imposed by the classic Bonse–Hart interferometer. The device operates in the far-field regime, where an incident beam is split by a diffraction grating into two widely separated beams, which are redirected by a second diffraction grating to merge at a third grating, where they coherently interfere. The wide separation of the interfering beams results in large phase contrast, and in some cases absolute phase images are obtained. Imaging experiments were performed using diffraction gratings of 200 nm period, at 22.5 keV and 1.5% spectral bandwidth on a bending-magnetic beamline. Novel design and fabrication process were used to achieve the small grating period. Using a slitted incident beam, we acquired absolute and differential phase images of lightly absorbing samples. An advantage of this method is that it uses only phase modulating gratings, which are easier to fabricate than absorption gratings of the same periods.

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Observation of the Talbot effect using broadband hard x-ray beam

Cited by 25 publications

References 11 publications

Interferometric hard x-ray phase contrast imaging at 204 nm grating period

Interferometric hard x-ray phase contrast imaging at 204 nm grating period

Fabrication of 200 nm period centimeter area hard x-ray absorption gratings by multilayer deposition

Boosting phase contrast with a grating Bonse–Hart interferometer of 200 nanometre grating period

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Observation of the Talbot effect using broadband hard x-ray beam

Cited by 25 publications

References 11 publications

Interferometric hard x-ray phase contrast imaging at 204 nm grating period

Interferometric hard x-ray phase contrast imaging at 204 nm grating period

Fabrication of 200 nm period centimeter area hard x-ray absorption gratings by multilayer deposition

Boosting phase contrast with a grating Bonse–Hart interferometer of 200 nanometre grating period

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Product

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Observation of the Talbot effect using broadband hard x-ray beam