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Light, Waves, and Rays
Published in Vincent Toal, Introduction to Holography, 2011
Physical optics is the study of the behavior of light. When light encounters an aperture or obstacle or a change in refractive index, its direction of propagation and its phase are both altered. This effect, known as diffraction, is an important aspect of physical optics. Another important behavior that light exhibits is interference, which happens when light waves encounter one another usually having traveled rather different routes. A third and extremely important property of light is its coherence, and a fourth is its state of polarization. All these aspects of light are of great importance for holography, and we will examine each of them.
Physics
Published in Keith L. Richards, Design Engineer's Sourcebook, 2017
Optics is the study of the nature and behavior of light and can be divided into subdisciplines based on the type of model used to describe light:In physical optics, light is assumed to behave like a classical wave.In quantum optics, light is assumed to have both wave and particle properties.
Typical Applications for Computer Vision
Published in Ravi Das, Practical AI for Cybersecurity, 2021
One of the key aspects in Computer Vision as it used by the ANN system is what is known as “Optics.” What exactly is Optics? It can be defined technically as follows:Classical optics is divided into two main branches: geometrical (or ray) optics and physical (or wave) optics. In geometrical optics, light is considered to travel in straight lines, while in physical optics, light is considered as an electromagnetic wave.
Divergence factor correction of shooting and bouncing ray method for triangular meshed curved targets
Published in Waves in Random and Complex Media, 2023
Hao Wang, Bing Wei, Hongwei Liu
The study of radar cross section (RCS) simulation of large and complex targets is a hot research topic in many fields. In the high-frequency regime, the asymptotic approximation method has less computation memory and time than the exact numerical method [1,2]. The shooting and bouncing ray (SBR) method was first proposed in [3]. Due to the consideration of coupled scattering between different parts of the target, the method has high accuracy and is widely used to compute arbitrary shape targets [4–8]. In SBR, the incident plane wave is simulated with dense ray tubes and ray tracing is then performed according to geometrical optics (GO) to determine the field on the target surface. The scattering field is finally obtained by the physical optics (PO) integral of the surface induced current.
Calculation of the statistical characteristics of the light reflected by a rough random cylindrical homogeneous Gaussian surface
Published in Journal of Modern Optics, 2018
Rauf Gardashov, Gökhan Kara, E. Gül Emecen Kara
As is seen from expressions (7) and (10), the method of specular points yields the result which coincides with that obtained by the method of stochastically distributed facets for the average intensity, but gives a divergent result for the intensity fluctuation (because and, consequently, as it follows from (11) that, and ). The origin of this divergence is hidden in the fact that the specular point with a zero curvature (this point is the points of inflection) appears among the whole set of specular points, and geometrical optics yields an infinity intensity of reflected light at such point (caustic point, or caustic). At a caustic point, two specular points merge, and the incoherent addition of reflected beams underlying formula (6) becomes incorrect. We eliminate this divergence using the procedure suggested in Ref. (4) for calculating the intensity near caustic. According to this procedure, the contribution of each specular point to the sum (6) is redefined as follows: where, and is a parameter determining the width of the caustic zone, – wave number of light. The parameter is determined from the condition that physical optics (Airy function) and geometrical optics gives the same value for reflected intensity.
Scattering by a perfectly conducting convex hyperbolic reflector
Published in Journal of Modern Optics, 2019
Reflectors are mainly used in dual reflector systems consisting of one main reflector and one subreflector (1). Gregorian and Cassegrain systems can be given as the examples of these kinds of systems. Several studies have been performed due to the common usage of dual reflector systems in antenna applications (2–10). The scattering and radiation behaviour of dual reflector systems have also been investigated by using scattering methods that can be divided into two categories: ray-based techniques and current-based techniques. The geometrical optics (GO) (11), the geometrical theory of diffraction (GTD) (12), the uniform asymptotic theory of diffraction (UAT) (13) and the uniform theory of diffraction (UTD) (14) are the methods of the ray-based techniques; the physical theory of diffraction (PTD) (15), the physical optics (PO) (16) and the modified theory of physical optics (MTPO) (17) are the examples of the current-based techniques. Among these methods, MTPO that is a current-based technique which was suggested by Umul in 2004 (17) was shown that it gives more reliable results than the well-known theory of PO for the achievement of the exact diffracted fields from the edge points of scatterers, especially. Umul applied his theory to several canonical surfaces such as the impedance surface of half plane (18). He also examined the diffraction by a conducting wedge using the method of MTPO (19), the scattering problem of half plane having the different face impedances (20) and the scattering integral of MTPO for the unlit surface (21) to show his theory’s reliability and usefulness.