Measurement of the diffusion coefficient in liquids using Fresnel diffraction from a phase step

Abstract Fresnel diffraction from a phase step for measuring diffusion coefficient in transparent liquids is investigated. When a transparent glass plate immersed vertically in a cell containing two diffusing liquids is illuminated by a parallel beam of light, the diffraction pattern of the plate edge forms on a screen perpendicular to the beam direction and varies by diffusion. The gradient of the refractive index in the liquids is then obtained by analyzing the diffraction patterns at different times after the beginning of the diffusion process, from which the diffusion coefficient is determined. Using this method, we study the diffusion process of the sucrose-water solution and report the diffusion coefficient with a reliable accuracy.

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Calculation of Fresnel diffraction from 1D phase step by discrete Fourier transform

Optics Communications ◽

10.1016/j.optcom.2016.08.031 ◽

2017 ◽

Vol 382 ◽

pp. 651-655 ◽

Cited By ~ 8

Author(s):

Rasoul Aalipour

Keyword(s):

Fourier Transform ◽

Discrete Fourier Transform ◽

Fresnel Diffraction ◽

Phase Step

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Application of Fresnel diffraction from a phase step to determination of the spectral line profile

Journal of Optics ◽

10.1088/2040-8986/aad82c ◽

2018 ◽

Vol 20 (9) ◽

pp. 095606 ◽

Cited By ~ 4

Author(s):

Khosrow Hassani ◽

Ameneh Jabbari ◽

Mohammad Taghi Tavassoly

Keyword(s):

Spectral Line ◽

Line Profile ◽

Fresnel Diffraction ◽

Phase Step ◽

Spectral Line Profile

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Spectral modification by line singularity in Fresnel diffraction from 1D phase step

Optics Communications ◽

10.1016/j.optcom.2005.06.048 ◽

2005 ◽

Vol 255 (1-3) ◽

pp. 23-34 ◽

Cited By ~ 25

Author(s):

M.T. Tavassoly ◽

M. Amiri ◽

E. Karimi ◽

H.R. Khalesifard

Keyword(s):

Fresnel Diffraction ◽

Phase Step ◽

Spectral Modification ◽

Line Singularity

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Measuring source width and transverse coherence length using Fresnel diffraction from a phase step

Applied Optics ◽

10.1364/ao.397748 ◽

2020 ◽

Vol 59 (25) ◽

pp. 7712

Author(s):

Rasoul Aalipour ◽

Mohammad Taghi Tavassoly ◽

Ahad Saber

Keyword(s):

Coherence Length ◽

Fresnel Diffraction ◽

Phase Step

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Application of Fresnel diffraction from a phase step to the measurement of film thickness

Applied Optics ◽

10.1364/ao.48.005497 ◽

2009 ◽

Vol 48 (29) ◽

pp. 5497 ◽

Cited By ~ 24

Author(s):

Mohammad Taghi Tavassoly ◽

Iman Moaddel Haghighi ◽

Khosrow Hassani

Keyword(s):

Film Thickness ◽

Fresnel Diffraction ◽

Phase Step

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Observation of Phase Contrast Images in STEM and CTEM Modes by Using 100 kV Field Emission Electron Gun

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100051967 ◽

1974 ◽

Vol 32 ◽

pp. 390-391

Author(s):

Y. Harada ◽

T. Goto ◽

H. Koike ◽

T. Someya

Keyword(s):

Field Emission ◽

Phase Contrast ◽

Image Formation ◽

Fresnel Diffraction ◽

Experimental Results ◽

Electron Gun ◽

Scanning Microscopy ◽

Emission Electron ◽

Lattice Images

Since phase contrasts of STEM images, that is, Fresnel diffraction fringes or lattice images, manifest themselves in field emission scanning microscopy, the mechanism for image formation in the STEM mode has been investigated and compared with that in CTEM mode, resulting in the theory of reciprocity. It reveals that contrast in STEM images exhibits the same properties as contrast in CTEM images. However, it appears that the validity of the reciprocity theory, especially on the details of phase contrast, has not yet been fully proven by the experiments. In this work, we shall investigate the phase contrast images obtained in both the STEM and CTEM modes of a field emission microscope (100kV), and evaluate the validity of the reciprocity theory by comparing the experimental results.

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Simulation of high-resolution annular dark field STEM images

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010013657x ◽

1995 ◽

Vol 53 ◽

pp. 40-41

Author(s):

E. J. Kirkland

Keyword(s):

Electron Beam ◽

Atomic Layer ◽

Fresnel Diffraction ◽

Dark Field ◽

Objective Lens ◽

Image Simulation ◽

Small Probe ◽

Annular Dark Field ◽

Stem Image ◽

Uniform Plane

In a STEM an electron beam is focused into a small probe on the specimen. This probe is raster scanned across the specimen to form an image from the electrons transmitted through the specimen. The objective lens is positioned before the specimen instead of after the specimen as in a CTEM. Because the probe is focused and scanned before the specimen, accurate annular dark field (ADF) STEM image simulation is more difficult than CTEM simulation. Instead of an incident uniform plane wave, ADF-STEM simulation starts with a probe wavefunction focused at a specified position on the specimen. The wavefunction is then propagated through the specimen one atomic layer (or slice) at a time with Fresnel diffraction between slices using the multislice method. After passing through the specimen the wavefunction is diffracted onto the detector. The ADF signal for one position of the probe is formed by integrating all electrons scattered outside of an inner angle large compared with the objective aperture.

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