Fresnel diffraction from a step in the general case

Salvdari, Hamid; Tavassoly, Mohammad Taghi; Hosseini, Seyed Roohollah

doi:10.1364/josaa.34.000674

Cited by 17 publications

(5 citation statements)

References 25 publications

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“…For 1 t  , Eq. (10) reduces to [16]: V is a universal curve for 0  in the interval of 02   . This allows us to specify the experimental normalized intensity profiles accurately by fitting them on the corresponding universal curves.…”

Section: Fresnel Diffraction From a Phase Stepmentioning

confidence: 99%

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Fresnel Diffraction from Phase Steps and Its Applications

Tavassoly

Salvdari

2020

IJOP

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The well-established Fresnel diffraction occurs as an opaque object partially obstructs the passage of a coherent beam of light. In this process, the amplitude of the optical wave experiences a discontinuous change that leads to peculiar bright and dark fringes near the ray optics border of the beam. The fringe pattern varies very slowly by distance from the object and away from the beam border the diffraction effect is negligible. These behaviors have limited the applications of the conventional Fresnel diffraction very severely. In this article, we introduce a new kind of Fresnel diffraction that occurs due to discontinuous change in phase or phase gradient, in a part of a coherent beam of light. The change splits the beam into two diffracting wavefronts with common border that interfere with each other. In this kind of diffraction, the fringes may appear in the central part of the beam and their locations and visibilities are very sensitive to the phase change. Therefore, the researchers have utilized the effect in the measurements of different physical quantities, with high accuracy, using modest equipment. In this article, we use the Fresnel diffraction from the semi-infinite opaque screen (knife-edge) as the building block to describe the introduced effect, diffraction from the phase steps, and discuss its different aspects. We simulate the implied diffraction patterns, investigate the patterns by experiments, elaborate on the unique features of the effect, and present some interesting applications.

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Section: Fresnel Diffraction From a Phase Stepmentioning

confidence: 99%

“…Derivation of the amplitudes and phase difference for wavefronts emerging from a phase step with arbitrary orientation of its surfaces is rather complex [13,16]. Therefore, we do not consider here, and conclude the section by presenting some relevant simulations.…”

Section: Sohmentioning

confidence: 99%

Fresnel Diffraction from Phase Steps and Its Applications

Tavassoly

Salvdari

2020

IJOP

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“…Recently it has been shown that discontinuous changes in phase or phase gradient of the light beam leads to an appreciable diffraction that is referred to as Fresnel diffraction from phase steps [11,12]. This effect was studied theoretically and experimentally [13,14], and applied to a plenty interesting metrological measurements. The measurements include refractive indices of materials with high accuracy [15][16][17][18], nonlinear refractive index [19], thickness of thin films and plates [20], nanometer displacement [21], wavelength, and spectral line profile [17,22].…”

Section: Introductionmentioning

confidence: 99%

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

2021

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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 Send offprint requests to: Ahad Saber 2 Ahad Saber et al.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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“…Thus far, Fresnel diffraction from a phase step is studied [27][28][29] and widely considered in the context of different metrological applications, e.g., the measurement of refractive indices of solids and liquids [30][31][32], thickness of films and plates [33], focal length of an imaging system [34], etching rate of glass steps [35], and determination of the off-axis angle and the wavelength of light [36].…”

Section: Introductionmentioning

confidence: 99%

Quantitative phase imaging based on Fresnel diffraction from a phase plate

Ebrahimi

Dashtdar

2019

Applied Physics Letters

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The structural complexity and instability of many interference phase microscopy methods are the major obstacles toward high-precision phase measurement. In this vein, improving more efficient configurations as well as proposing new methods are the subjects of growing interest. Here we introduce Fresnel diffraction from a phase step to the realm of quantitative phase imaging. By employing Fresnel diffraction of a divergent (or convergent) beam of light from a plane-parallel phase plate, we provide a viable, simple and compact platform for three-dimensional imaging of micron-sized specimens. The recorded diffraction pattern of the outgoing light from an imaging system in the vicinity of the plate edge can be served as a hologram, which would be analyzed via Fourier transform method to measure the sample phase information. The period of diffraction fringes is adjustable simply by rotating the plate without the reduction of both field of view and fringe contrast. The high stability of the presented method is affirmatively confirmed through comparison the result with that of conventional Mach-Zehnder based digital holographic method. Quantitative phase measurements on silica microspheres, onion skin and red blood cells ensure the validity of the method and its ability for monitoring nanometer-scale fluctuations of living cells, particularly in real-time.

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Fresnel diffraction from a step in the general case

Cited by 17 publications

References 25 publications

Fresnel Diffraction from Phase Steps and Its Applications

Fresnel Diffraction from Phase Steps and Its Applications

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

Quantitative phase imaging based on Fresnel diffraction from a phase plate

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