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We present a general theory of fractal transformations and show how it leads to a new type of method for filtering and transforming digital images. This work substantially generalizes earlier work on fractal tops. The approach involves…

Geometric Topology · Mathematics 2011-02-17 Michael F. Barnsley , Brendan Harding , Konstantin Igudesman

We have recorded the coherent diffraction images of individual xenon clusters with intense extreme ultraviolet pulses to elucidate the influence of light-induced electronic changes on the diffraction pattern. Using the FLASH free-electron…

Gratings and holograms are patterned surfaces that tailor optical signals by diffraction. Despite their long history, variants with remarkable functionalities continue to be discovered. Further advances could exploit Fourier optics, which…

Thick diffractive optical elements offer a promising way to achieve focusing or imaging at a resolution approaching 1 nm for X-ray wavelengths shorter than about 0.1 nm. Efficient focusing requires that these are fabricated with structures…

Optics · Physics 2020-12-02 Henry N. Chapman , Saša Bajt

Many natural patterns and shapes, such as meandering coastlines, clouds, or turbulent flows, exhibit a characteristic complexity mathematically described by fractal geometry. In recent years, the engineering of self-similar structures in…

Glass is very common in the real world. Influenced by the uncertainty about the glass region and the varying complex scenes behind the glass, the existence of glass poses severe challenges to many computer vision tasks, making glass…

Computer Vision and Pattern Recognition · Computer Science 2022-09-14 Letian Yu , Haiyang Mei , Wen Dong , Ziqi Wei , Li Zhu , Yuxin Wang , Xin Yang

By slight modification of the data of the Sierpinski gasket, keeping the open set condition fulfilled, we obtain self-similar sets with very dense parts, similar to fractals in nature and in random models. This is caused by a complicated…

Dynamical Systems · Mathematics 2023-01-02 Christoph Bandt , Dmitry Mekhontsev

In this work, the properties of the radiation emitted by a corner reflector with an electric dipole feeder are analyzed in the optical domain where the distance between the dipole and the corner apex can be large in terms of the optical…

Optics · Physics 2024-01-01 Pedro Chamorro-Posada

Atomic systems have long provided a useful material platform with unique quantum properties. The efficient light-matter interaction in atomic vapors has led to numerous seminal scientific achievements including accurate and precise…

Optics · Physics 2018-12-05 Liron Stern , Douglas Bopp , Susan Schima , Vincent Maurice , John Kitching

Self-projective sets are natural fractal sets which describe the action of a semigroup of matrices on projective space. In recent years there has been growing interest in studying the dimension theory of self-projective sets, as well as…

Dynamical Systems · Mathematics 2024-02-20 Argyrios Christodoulou , Natalia Jurga

Gradient index sonic lenses based on two-dimensional sonic crystals are here designed, fabricated and characterized. The index-gradient is achieved in these type of flat lenses by a gradual modification of the sonic crystal filling fraction…

Materials Science · Physics 2015-05-19 Alfonso Climente , Daniel Torrent , Jose Sanchez-Dehesa

We present a theoretical study of a spectral filter, which consists of a diffraction grating, a coupling lens, and an optical fiber. As the diffracted beam is highly dispersed spatially, coupling into an optical fiber naturally creates a…

Optics · Physics 2025-03-25 Seonjong Ryu , Jinpyo Jeong , Mintae Kang , Taemin Son , Andy Chong

An extension of the Gutzwiller trace formula is given that includes diffraction effects due to hard wall scatterers or other singularities. The new trace formula involves periodic orbits which have arcs on the surface of singularity and…

chao-dyn · Physics 2016-08-14 Gábor Vattay , Andreas Wirzba , Per E. Rosenqvist

Different theoretical methods used for the description of diffractive processes in small-x deep inelastic scattering are reviewed. The semiclassical approach, where a partonic fluctuation of the incoming virtual photon scatters off a…

High Energy Physics - Phenomenology · Physics 2009-02-20 A. Hebecker

Different omnidirectional refractive devices for flexural waves in thin plates are proposed and numerically analyzed. Their realization is explained by means phononic crystal plates, where a previously developed homogenization theory is…

Materials Science · Physics 2015-06-23 Daniel Torrent , Yan Pennec , Bahram Djafari-Rouhani

Lens flare is a common image artifact that can significantly degrade image quality and affect the performance of computer vision systems due to a strong light source pointing at the camera. This survey provides a comprehensive overview of…

Image and Video Processing · Electrical Eng. & Systems 2023-10-24 Yousef Kotp , Marwan Torki

Passive optical elements can play key roles in photonic applications such as plasmonic integrated circuits. Here we experimentally demonstrate passive gap-plasmon focusing and routing in two-dimensions. This is accomplished using a high…

The super-oscillation lens (SOL) can achieve super-resolution focusing but have to trade-off with weaker hotspots and higher sidebands. We propose a single compound SOL to achieve reflective confocal imaging in principle without additional…

This preliminary paper presents initial explorations in rendering Iterated Function System (IFS) fractals using a differentiable rendering pipeline. Differentiable rendering is a recent innovation at the intersection of computer graphics…

Graphics · Computer Science 2024-06-11 Cory Braker Scott

Laue lenses are an emerging technology based on diffraction in crystals that allows the concentration of soft gamma rays. This kind of optics that works in the 100 keV - 1.5 MeV band can be used to realize an high-sensitivity and…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 N. Barriere , L. Natalucci , N. Abrosimov , P. von Ballmoos , P. Bastie , P. Courtois , M. Jentschel , J. Knodlseder , J. Rousselle , P. Ubertini