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A fundamental issue that limits the efficiency of many photoelectrochemical systems is that the photon absorption length is typically much longer than the electron diffusion length. Various photon management schemes have been developed to…

Imaging of scenes using light or other wave phenomena is subject to the diffraction limit. The spatial profile of a wave propagating between a scene and the imaging system is distorted by diffraction resulting in a loss of resolution that…

Image and Video Processing · Electrical Eng. & Systems 2020-07-20 Ji Hyun Nam , Andreas Velten

We demonstrate experimentally that long-range intensity correlation for light propagating inside random photonic waveguides can be modified by changing the shape of the waveguide. The functional form of spatial correlation is no longer…

Optics · Physics 2017-03-30 Raktim Sarma , Alexey Yamilov , Pauf Neupane , Hui Cao

In this paper, a linear model based on multiple measurement vectors model is proposed to formulate the inverse scattering problem of highly conductive objects at one single frequency. Considering the induced currents which are mostly…

Signal Processing · Electrical Eng. & Systems 2019-06-27 Shilong Sun , Bert Jan Kooij , Alexander G. Yarovoy

Image stitching from different captures often results in non-rectangular boundaries, which is often considered unappealing. To solve non-rectangular boundaries, current solutions involve cropping, which discards image content, inpainting,…

Computer Vision and Pattern Recognition · Computer Science 2024-03-29 Tianhao Zhou , Haipeng Li , Ziyi Wang , Ao Luo , Chen-Lin Zhang , Jiajun Li , Bing Zeng , Shuaicheng Liu

In the context of providing a mathematical framework for the propagation of ultrasound waves in a random multiscale medium, we consider the scattering of classical waves (modeled by a divergence form scalar Helmholtz equation) by a bounded…

Analysis of PDEs · Mathematics 2023-09-15 Josselin Garnier , Laure Giovangigli , Quentin Goepfert , Pierre Millien

We report on experiments that were performed with microwave waveguide systems and demonstrate that in the frequency range of a single transversal mode they may serve as a model for closed and open quantum graphs. These consist of bonds that…

Quantum Physics · Physics 2023-05-30 Weihua Zhang , Xiaodong Zhang , Jiongning Che , Junjie Lu , M. Miski-Oglu , Barbara Dietz

Resonant transmission occurs when constructive interference results in the complete passage of an incoming wave through an array of barriers. In this paper we explore such a scenario with one dimensional models. We adopt wave packets with…

Quantum Physics · Physics 2023-10-11 A. M. Michalik , F. Marsiglio

This paper is concerned with the inverse problem of time-harmonic acoustic scattering by an unbounded, locally rough interface which is assumed to be a local perturbation of a plane. The purpose of this paper is to recover the local…

Analysis of PDEs · Mathematics 2020-08-05 Jianliang Li , Jiaqing Yang , Bo Zhang

It is well known that direct observation of interference and diffraction pattern in the intensity distribution requires a spatially coherent source. Optical waves emitted from portions beyond the coherence area possess statistically…

Optics · Physics 2009-11-13 Su-Heng Zhang , Lu Gao , Jun Xiong , Li-Juan Feng , De-Zhong Cao , Kaige Wang

We discuss the far-field spatio-temporal cross-correlations of waves multiple-scattered in a turbid medium in which is embedded a hidden heterogeneous region (inclusion) characterized by a distinct scatterer dynamics (as compared to the…

Soft Condensed Matter · Physics 2007-05-23 S. E. Skipetrov

Improving the image contrast of objects immersed in weakly scattering media can be achieved using various strategies. One common approach is to reject events associated with scattered photons in favor of the detection of ballistic photons.…

Coupled waveguides are convenient at implementing useful optical transformations. In this letter, we investigate the uncertainty of transformation by two coupled waveguides that stems from the perturbations of waveguide's mode indices~---…

Optics · Physics 2018-05-11 M. Yu. Saygin

We discuss and briefly overview recent progress with studying fluctuations in scattering on a resonance state coupled to the background of many chaotic states. Such a problem arises naturally, e.g., when dealing with wave propagation in the…

Quantum Physics · Physics 2017-12-21 D. V. Savin

Guidance is a crucial technique for extracting the best performance out of image-generating diffusion models. Traditionally, a constant guidance weight has been applied throughout the sampling chain of an image. We show that guidance is…

Computer Vision and Pattern Recognition · Computer Science 2024-11-07 Tuomas Kynkäänniemi , Miika Aittala , Tero Karras , Samuli Laine , Timo Aila , Jaakko Lehtinen

This paper investigates the inverse biharmonic scattering problems of identifying the shape and location of the obstacle with phased and phaseless measurement data. A direct imaging method based on reverse time migration is proposed for…

Analysis of PDEs · Mathematics 2026-05-12 Tielei Zhu , Zhihao Ge

We provide a theoretical framework to describe the interaction of a propagating guided matter wave with a localized potential in terms of quantum scattering in a confined environment. We analyze how this scattering correlates the…

Other Condensed Matter · Physics 2010-09-10 Giovanni Luca Gattobigio , Antoine Couvert , Bertrand Georgeot , David Guéry-Odelin

Getting to grips with the detrimental influence of disordered environments on wave propagation is an interdisciplinary endeavour spanning diverse research areas ranging from telecommunications \cite{basar_wireless_2019} and bio-medical…

We present theoretical calculations of the ensemble-averaged (a.k.a. effective or coherent) wavefield propagating in a heterogeneous medium considered as one realization of a random process. In the literature, it is usually assumed that…

Classical Physics · Physics 2015-09-30 Ibrahim Baydoun , Diego Baresch , Romain Pierrat , Arnaud Derode

We present a comparative study of two qualitative imaging methods in an acoustic waveguide with sound hard walls. The waveguide terminates at one end and contains unknown obstacles of compact support, to be determined from data gathered by…

Analysis of PDEs · Mathematics 2020-01-08 Liliana Borcea , Shixu Meng
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