Polarization analysis of the object wave using FMCW-digital holography

2019 ◽  
Author(s):  
Masayuki Yokota ◽  
T. Ishikawa ◽  
N. Aoki
Keyword(s):  
Digital Holography ◽  
Object Wave ◽  
Polarization Analysis

Complex object wave extraction using time-multiplexing in off-axis digital holography

2017 ◽  
Vol 57 (1) ◽  
pp. A50 ◽  
Author(s):  
Erkhembaatar Dashdavaa ◽  
Munkh-Uchral Erdenebat ◽  
Chang-Won Shin ◽  
Nam Kim
Keyword(s):  
Digital Holography ◽  
Object Wave ◽  
Complex Object

scholarly journals Complex object wave direct extraction method in off-axis digital holography

2013 ◽  
Vol 21 (3) ◽  
pp. 3658 ◽  
Author(s):  
Daesuk Kim ◽  
Robert Magnusson ◽  
Moonseob Jin ◽  
Jaejong Lee ◽  
Won Chegal
Keyword(s):  
Extraction Method ◽  
Digital Holography ◽  
Object Wave ◽  
Complex Object ◽  
Direct Extraction

Object wave retrieval using normalized holograms in three-step generalized phase-shifting digital holography

2019 ◽  
Vol 58 (5) ◽  
pp. A161 ◽  
Author(s):  
Nobukazu Yoshikawa ◽  
Syouma Namiki ◽  
Atsushi Uoya
Keyword(s):  
Digital Holography ◽  
Phase Shifting ◽  
Object Wave

Object Wave Determination by Single-Sideband Methods

1973 ◽  
Vol 31 ◽  
pp. 266-267
Author(s):  
Kenneth H. Downing ◽  
Benjamin M. Siegel
Keyword(s):  
Phase Shift ◽  
Carbon Films ◽  
Object Wave ◽  
Electron Wave ◽  
Phase Object ◽  
Heavy Atoms ◽  
Single Sideband ◽  
Thin Carbon ◽  
Additional Phase Shift ◽  
Additional Phase

Under the “weak phase object” approximation, the component of the electron wave scattered by an object is phase shifted by π/2 with respect to the unscattered component. This phase shift has been confirmed for thin carbon films by many experiments dealing with image contrast and the contrast transfer theory. There is also an additional phase shift which is a function of the atomic number of the scattering atom. This shift is negligible for light atoms such as carbon, but becomes significant for heavy atoms as used for stains for biological specimens. The light elements are imaged as phase objects, while those atoms scattering with a larger phase shift may be imaged as amplitude objects. There is a great deal of interest in determining the complete object wave, i.e., both the phase and amplitude components of the electron wave leaving the object.

Electron holography in materials science

1991 ◽  
Vol 49 ◽  
pp. 670-671
Author(s):  
Hannes Lichte ◽  
Edgar Voelkl
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Materials Science ◽  
Fourier Spectrum ◽  
Object Wave ◽  
Electron Holography ◽  
Reconstruction Procedure ◽  
Numerical Reconstruction ◽  
Transmission Electron ◽  
Unique Interpretation

The object wave o(x,y) = a(x,y)exp(iφ(x,y)) at the exit face of the specimen is described by two real functions, i.e. amplitude a(x,y) and phase φ(x,y). In stead of o(x,y), however, in conventional transmission electron microscopy one records only the real intensity I(x,y) of the image wave b(x,y) loosing the image phase. In addition, referred to the object wave, b(x,y) is heavily distorted by the aberrations of the microscope giving rise to loss of resolution. Dealing with strong objects, a unique interpretation of the micrograph in terms of amplitude and phase of the object is not possible. According to Gabor, holography helps in that it records the image wave completely by both amplitude and phase. Subsequently, by means of a numerical reconstruction procedure, b(x,y) is deconvoluted from aberrations to retrieve o(x,y). Likewise, the Fourier spectrum of the object wave is at hand. Without the restrictions sketched above, the investigation of the object can be performed by different reconstruction procedures on one hologram. The holograms were taken by means of a Philips EM420-FEG with an electron biprism at 100 kV.

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.

Imaging magnetic microstructure with SEMPA

1993 ◽  
Vol 51 ◽  
pp. 1032-1033
Author(s):  
M. H. Kelley ◽  
J. Unguris ◽  
R. J. Celotta ◽  
D. T. Pierce
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Scanning Electron Microscopy ◽  
Sandwich Structure ◽  
Magnetic Coupling ◽  
Polarization Analysis ◽  
Secondary Electrons ◽  
Magnetic Microstructure ◽  
Escape Depth ◽  
Scanning Electron

By measuring the spin polarization of secondary electrons generated in a scanning electron microscope, scanning electron microscopy with polarization analysis (SEMPA) can directly image the magnitude and direction of a material’s magnetization. Because the escape depth of the secondaries is only on the order of 1 nm, SEMPA is especially well-suited for investigating the magnetization of ultra-thin films and surfaces. We have exploited this feature of SEMPA to study the magnetic microstrcture and magnetic coupling in ferromagnetic multilayers where the layers may only be a few atomic layers thick. For example, we have measured the magnetic coupling in Fe/Cr/Fe(100) and Fe/Ag/Fe(100) trilayers and have found that the coupling oscillates between ferromagnetic and antiferromagnetic as a function of the Cr or Ag spacer thickness.The SEMPA apparatus has been described in detail elsewhere. The sample consisted of a magnetic sandwich structure with a wedge-shaped interlayer as shown in Fig. 1.

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