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Related papers: Negative refraction of Lamb modes: A theoretical s…

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We present subwavelength resonant lattices fashioned as nano- and microstructured films as a basis for a host of device concepts. Whereas the canonical physical properties are fully embodied in a one-dimensional periodic lattice, the final…

Orientation mapping is a widely used technique for revealing the microstructure of a polycrystalline sample. The crystalline orientation at each point in the sample is determined by analysis of the diffraction pattern, a process known as…

Mathematical Physics · Physics 2017-10-11 Peter Mahler Larsen , Søren Schmidt

Diffusion models have recently exhibited remarkable abilities to synthesize striking image samples since the introduction of denoising diffusion probabilistic models (DDPMs). Their key idea is to disrupt images into noise through a fixed…

Computer Vision and Pattern Recognition · Computer Science 2023-03-28 Zijian Zhang , Zhou Zhao , Jun Yu , Qi Tian

Diffusion-based posterior sampling (PS) is a leading framework for imaging inverse problems, combining learned priors with measurement constraints. Yet, its standard formulations rely on instantaneous data-consistent estimates, which induce…

Computer Vision and Pattern Recognition · Computer Science 2026-05-14 Davide Evangelista , Elena Morotti , Francesco Pivi , Maurizio Gabbrielli

The inverse problem of backward diffusion is known to be ill-posed and highly unstable. Backward diffusion processes appear naturally in image enhancement and deblurring applications. It is therefore greatly desirable to establish a…

Numerical Analysis · Mathematics 2020-06-18 Leif Bergerhoff , Marcelo Cárdenas , Joachim Weickert , Martin Welk

Optical methods are most convenient to analyze spatially periodic patterns with wavevector $\bm q$ in a thin layer of a nematic liquid crystal. In the standard experimental setup a beam of parallel light with a 'short' wavelength $\lambda…

Soft Condensed Matter · Physics 2015-06-15 Werner Pesch , Alexei Krekhov

Promising applications in photonics are driven by the ability to fabricate crystal-quality metal thin films of controlled thickness down to a few nanometers. In particular, these materials exhibit a highly nonlinear response to optical…

Mesoscale and Nanoscale Physics · Physics 2023-08-21 A. Rodríguez Echarri , F. Iyikanat , S. Boroviks , N. Asger Mortensen , Joel D. Cox , F. Javier García de Abajo

The effect of Poisson's ratio to the reflector reshaping is investigated through mechanical study of reconfigurable reflectors in this paper. The value of Poisson's ratio corresponding to the minimum deforming stress is given and an auxetic…

Soft Condensed Matter · Physics 2021-11-09 Bin Xu , Houfei Fang , Yangqin He , Shuidong Jiang , Lan Lan

Diffraction of electromagnetic plane waves by the gratings made by periodically corrugating the exposed planar boundaries of homogeneous, isotropic, linear dielectric--magnetic half--spaces is examined. The phase velocity vector in the…

Optics · Physics 2009-11-10 Ricardo A. Depine , Akhlesh Lakhtakia

In this paper, we study the propagation of the Frozen Wave type beams through non-absorbing stratified media and develop a theoretical method capable to provide the desired spatially shaped diffraction resistant beam in the last material…

Photonic metamaterials allow for a range of exciting applications unattainable with ordinary dielectrics. However, the metallic nature of their meta-atoms may result in increased optical losses. Gain-enhanced metamaterials are a potential…

This research focuses on a coherently driven four-level atomic medium with the aim of inducing a negative index of refraction while taking into consideration local field corrections as well as magnetoelectric cross coupling, i.e. chirality,…

Materials Science · Physics 2011-07-06 F. Bello

The importance of spatial non-locality in the description of negative refraction in electromagnetic materials has been put forward recently. We develop a theory of negative refraction in homogeneous and isotropic media, based on first…

Optics · Physics 2017-04-05 Davide Forcella , Claire Prada , Rémi Carminati

With a conventional lens sharpness of the image is always limited by the wavelength of light. An unconventional alternative to a lens, a slab of negative refractive index material, has the power to focus all Fourier components of a 2D…

Optics · Physics 2025-07-03 JB Pendry

Reflection at relativistically moving plasma mirrors is a well-known approach for frequency conversion as an alternative to nonlinear techniques. A key issue with plasma mirrors is the need for a high carrier concentration, of order 10^21…

Magnetic-free nonreciprocal optical devices that can prevent backscattering of signals are essential for integrated optical information processing. The achieved nonreciprocal behaviors mostly rely on various dispersive effects in optical…

Metamaterials with simultaneous negative permittivity and negative permeability (also called left-handed materials) open new avenues to achieving unprecedented physical properties and functionality unattainable with naturally occurring…

Optics · Physics 2010-03-16 S. He , Y. He , Y. Jin , J. He

To date, nearly all the reported Lamb wave resonators (LWRs) are straight crested LWRs, which suffer from inherent spurious modes and low quality factors (Q). For the first time, this work demonstrates a circular crested LWR. Its advantages…

Applied Physics · Physics 2025-01-03 Xianzheng Lu , Liang Lou , Hao Ren

Negative Prompting (NP) is widely utilized in diffusion models, particularly in text-to-image applications, to prevent the generation of undesired features. In this paper, we show that conventional NP is limited by the assumption of a…

Computer Vision and Pattern Recognition · Computer Science 2025-06-12 Felix Koulischer , Johannes Deleu , Gabriel Raya , Thomas Demeester , Luca Ambrogioni

In this paper, we show by experiment that by covering a thin flat nonlinear lens on the sources, the sub-diffraction-limit observation can be achieved by measuring either the near-field distribution or the far-field radiation of the sources…