A method of hard X-ray phase-shifting digital holography

2016 ◽  
Vol 23 (4) ◽  
pp. 1024-1029
Author(s):  
So Yeong Park ◽  
Chung Ki Hong ◽  
Jun Lim
Keyword(s):  
Phase Shift ◽  
Digital Holography ◽  
Relative Phase ◽  
Test Pattern ◽  
Fresnel Lens ◽  
Phase Shifting ◽  
New Method ◽  
Phase Plate ◽  
X Ray ◽  
Line Type

A new method of phase-shifting digital holography is demonstrated in the hard X-ray region. An in-line-type phase-shifting holography setup was installed in a 6.80 keV hard X-ray synchrotron beamline. By placing a phase plate consisting of a hole and a band at the focusing point of a Fresnel lens, the relative phase of the reference and objective beams could be successfully shifted for use with a three-step phase-shift algorithm. The system was verified by measuring the shape of a gold test pattern and a silica sphere.

Determination of Phase Shift by Digital Holography

2019 ◽  
Vol 888 ◽  
pp. 43-46
Author(s):  
Yoshitaka Takahashi ◽  
Masatoshi Saito ◽  
Toru Nakajima ◽  
Masakazu Shingu
Keyword(s):  
Phase Shift ◽  
Noise Reduction ◽  
Digital Holography ◽  
High Accuracy ◽  
Measured Data ◽  
Phase Shifting ◽  
Surface Shape ◽  
Shape Measurement ◽  
Phase Shifting Interferometry

In phase shifting interferometry phase shift is applied by various ways, but applying it with high accuracy, especially by LD current modulation, is not easy. In order to determine the accurate phase shift a new method has been proposed that the value of LD current corresponding to π/2 phase shift can be determined by phase shifting digital holography. The measured data of standard in surface shape measurement were used for calibration, and the obtained value was confirmed to cause noise reduction and improvement of holographic reconstructed images in digital holography.

Der Einfluß einer streuenden Phasenplatte auf das elektronenmikroskopische Bild

1970 ◽  
Vol 25 (5) ◽  
pp. 760-765 ◽  
Author(s):  
H. G. Badde ◽  
L. Beimer
Keyword(s):  
Phase Shift ◽  
Cross Section ◽  
Focal Plane ◽  
Phase Contrast ◽  
Carbon Film ◽  
Carbon Films ◽  
Phase Shifting ◽  
Phase Plate ◽  
Different Thickness ◽  
Coherent Part

Using carbon films for phase shifting in the focal plane of the objective one has to consider the decrease of the coherent part of the electron beam. Only the unscattered part contributes to the phase contrast. After passing a 90.8 nm carbon film with a phase shift of 2 π the coherent amplitude decreases to 47%. But using a phase plate of different thickness for shifting all scattered electrons like a Zernike λ/4-plate, there will be a larger increase of contrast in images of platinum and carbon atoms than by optimal defocussing phase contrast. Calculations of phase shift and decrease of zero beam amplitude up to 1 MeV are reported. The use of Be-films with lower scattering cross section offers no large advantage.

Phase-Shifting Method with Unknown Intervals in Phase-Shifting Digital Holography

2006 ◽  
Vol 3-4 ◽  
pp. 211-216
Author(s):  
T. Kita ◽  
Yoshiharu Morimoto ◽  
Motoharu Fujigaki ◽  
Toru Matui
Keyword(s):  
Phase Shift ◽  
Intensity Distribution ◽  
Digital Holography ◽  
Phase Distribution ◽  
Reference Beam ◽  
Spherical Wave ◽  
High Accuracy ◽  
Displacement Measurement ◽  
Phase Shifting ◽  
Phase Shifting Method

Displacement measurement can be performed with high accuracy using phase-shifting method. In phase-shifting method, it is often used four steps of phase-shifting for one cycle. In conventional method, to measure the displacement of an object by an interferometer, the phase of a reference beam should be shifted by every π/2 in the four-step phase-shifting. In this paper, a phase-shifting method with unknown intervals is proposed. This method does not need to shift a phase by every π/2. It can detect an intensity distribution and a phase distribution from five fringe images with equal intervals even if the phase-shift amount is unknown. Using this method, we propose a displacement measurement of phase-shifting digital holographic interferometry using spherical wave as reference wave.

scholarly journals Color Digital Holography Based on Generalized Phase-Shifting Algorithm with Monitoring Phase-Shift

Photonics ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 241
Author(s):  
Minwoo Jung ◽  
Hosung Jeon ◽  
Sungjin Lim ◽  
Joonku Hahn
Keyword(s):  
Phase Shift ◽  
Focal Plane ◽  
Digital Holography ◽  
Phase Shifter ◽  
Phase Shifting ◽  
Signal Wave ◽  
Color Filter ◽  
Object Image ◽  
Phase Shift Error ◽  
Monitoring Phase

Color digital holography (DH) has been researched in various fields such as the holographic camera and holographic microscope because it acquires a realistic color object wave by measuring both amplitude and phase. Among the methods for color DH, the phase-shifting DH has an advantage of obtaining a signal wave of objects without the autocorrelation and conjugate noises. However, this method usually requires many interferograms to obtain signals for all wavelengths. In addition, the phase-shift algorithm is sensitive to the phase-shift error caused by the instability or hysteresis of the phase shifter. In this paper, we propose a new method of color phase-shifting digital holography with monitoring the phase-shift. The color interferograms are recorded by using a focal plane array (FPA) with a Bayer color filter. In order to obtain the color signal wave from the interferograms with unexpected phase-shift values, we devise a generalized phase-shifting DH algorithm. The proposed method enables the robust measurement in the interferograms. Experimentally, we demonstrate the proposed algorithm to reconstruct the object image with negligibly small conjugate noises.

scholarly journals Robust phase-shift estimation method for statistical generalized phase-shifting digital holography

2014 ◽  
Vol 22 (12) ◽  
pp. 14155 ◽  
Author(s):  
Nobukazu Yoshikawa ◽  
Takaaki Shiratori ◽  
Kazuki Kajihara
Keyword(s):  
Phase Shift ◽  
Digital Holography ◽  
Estimation Method ◽  
Phase Shifting

Two-Step Phase-Shifting Digital Holography Based on Extraction of Phase Shift

2014 ◽  
Vol 41 (2) ◽  
pp. 0209014
Author(s):  
邓丽军 Deng Lijun ◽  
杨勇 Yang Yong ◽  
石炳川 Shi Bingchuan ◽  
马忠洪 Ma Zhonghong ◽  
盖琦 Ge Qi ◽  
...  
Keyword(s):  
Phase Shift ◽  
Digital Holography ◽  
Phase Shifting

A Method for Accurate Phase Shift in Two-step Phase-shifting Digital Holography

2011 ◽  
Vol 40 (8) ◽  
pp. 1282-1286
Author(s):  
秦怡 QIN Yi ◽  
巩琼 GONG Qiong ◽  
杨兴强 YANG Xing-qiang
Keyword(s):  
Phase Shift ◽  
Digital Holography ◽  
Phase Shifting

scholarly journals Investigation of hole-free phase plate performance in transmission electron microscopy under different operation conditions by experiments and simulations

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Rebecca Pretzsch ◽  
Manuel Dries ◽  
Simon Hettler ◽  
Martin Spiecker ◽  
Martin Obermair ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Phase Shift ◽  
Zero Order ◽  
Phase Shifting ◽  
Negative Phase ◽  
Phase Plate ◽  
Microscopy Imaging ◽  
Transmission Electron ◽  
Phase Plates

Abstract Hole-free phase plates (HFPPs), also known as Volta phase plates, were already demonstrated to be well suited for in-focus transmission electron microscopy imaging of organic objects. However, the underlying physical processes have not been fully understood yet. To further elucidate the imaging properties of HFPPs, phase shift measurements were carried out under different experimental conditions. Both positive and negative phase shifts occur depending on the diameter of the zero-order electron beam and the HFPP film temperature. The analysis of Thon ring patterns of an amorphous carbon test sample reveals that the phase-shifting patch can be significantly larger than the size of the zero-order beam on the HFPP film. An HFPP was used for in-focus phase contrast imaging of carbon nanotube (CNT) bundles under positive and negative phase-shifting conditions. The comparison of experimental and simulated images of CNT bundles gives detailed information on the phase shift profile, which depends on the spatial frequency in the vicinity of the zero-order beam. The shape of the phase shift profile also explains halo-like image artifacts that surround the imaged objects.

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