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Interference and Diffraction
Published in Toyohiko Yatagai, Fourier Theory in Optics and Optical Information Processing, 2022
The extent of the diffraction is proportional to the wavelength and inversely proportional to the size of the aperture. As shown in Fig. 2.6, due to the diffraction, the wave propagates behind the obstacle. The shorter the width of the aperture, more obvious is the diffraction effect, and therefore, the part of straight propagation is reduced. If the width of the aperture is the same as the wavelength, then the diffracted wave can be to be considered as a spherical wave. Therefore, in Sec. 2.3, the waves from slits were regarded as spherical waves. The integral of Eq. (2.29) means that the superposition of many spherical waves1 originating at the aperture plane gives the amplitude of the diffracted wave.
Petroleum Seismological Survey
Published in Muhammad Abdul Quddus, Petroleum Science and Technology, 2021
Diffraction is a phenomenon in which waves are bended, spread out and cause interference between the wave forms. It occurs when a wave encounters the edges of an object or passes through an orifice. The main cause of diffraction of seismic waves is the non-homogeneity of the layers such as edges of faulted layers, isolated and discrete accumulation of minerals and other materials forming edges and small openings. A discontinuity in the layer structure, with a radius of curvature less than the wavelength of the seismic wave, does not obey the laws of reflection/refraction. Instead diffraction of the seismic wave takes place. Diffraction is the scattering of waves. The diffracted wave originates from underground, appears on the surface and is considered an interfering noise wave.
Optical Nanosensors
Published in Vinod Kumar Khanna, Nanosensors, 2021
What is a diffraction grating? Diffraction grating is an optical device used to resolve the different wavelengths or colors contained in a beam of light. The device usually consists of thousands of narrow, equidistant, closely spaced, parallel slits (or grooves).
Spatial intensity correlations of Mathieu speckle fields
Published in Journal of Modern Optics, 2023
Cristian Hernando Acevedo, Yezid Torres Moreno, Jose Rafael Guzman-Sepulveda, Aristide Dogariu
Diffraction is an inherent phenomenon of wave dynamics by which they spread out after encountering an obstacle or an aperture. It also takes place under free propagation due to the finite size of the propagating wave. For optical waves, diffraction can be a limitation in applications where the shape of the beam needs to be kept invariant during propagation. To overcome this drawback, non-diffracting beams have been introduced as electromagnetic structured wave fields that satisfy the two-dimensional (2D) Helmholtz equation whose transverse intensity distribution does not change during free propagation [1]. Prominent examples of such non-diffracting beams are the well-known Bessel beams [2], Airy beams [3], and Parabolic beams [4], which have been used extensively in the fields of classical and quantum communications [5–8], optical micromanipulation [9–10], and other applications [11–13]. When the 2D Helmholtz wave equation is solved in elliptical coordinates, the non-diffracting solutions are the Mathieu beams [14–18]. These beams have been widely used to generate solitons in photonics lattices [19–22] due to their rich topological properties which can translate into fine modulations of the refractive index in nonlinear materials.
Steering light in fiber-optic medical devices: a patent review
Published in Expert Review of Medical Devices, 2022
Merle S. Losch, Famke Kardux, Jenny Dankelman, Benno H. W. Hendriks
Refraction is defined as the change in direction of a transmitted light beam after it enters a second medium. Reflection is defined as the change in direction of a light beam at an interface that returns the light beam back to the original medium. The angle of incidence of the light beam on the surface and the material properties of the two media determine the intensity and direction of the refracted and reflected light beam. Another way to steer light is scattering: multiple changes in refractive index force the light beam to randomly change direction in a series of reflection events, resulting in diffuse light scattering. Lastly, a fundamentally different method to steer a light beam is diffraction. Diffraction is defined as the bending of light after encountering a small opening or obstacle. The light beam does not bend in one direction; instead, a diffraction pattern is generated by the interference of different wave fronts. Diffraction is predominant for apertures and obstacles with sizes in the range of the wavelength of the incident light.
Ruling engines and diffraction gratings before Rowland: the work of Lewis Rutherfurd and William Rogers
Published in Annals of Science, 2018
Spectroscopy has been one of the most productive tools for research in the physical sciences. Diffraction gratings are an essential component of many spectroscopic instruments. During the last twenty years of the nineteenth century, Henry Rowland, Professor of Physics at Johns Hopkins University in Baltimore, was the sole source of diffraction gratings, and the ruling engines he built at Johns Hopkins continued to have a near-monopoly of diffraction grating supply for decades after his death in 1901.1 Rowland’s dominance has overshadowed the work of others in this field.