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We study optical pulse propagation through a hollow-core fiber filled with a radially inhomogeneous cloud of cold atoms. A co-propagating control field establishes electromagnetically induced transparency. In analogy to a graded index…

Atomic Physics · Physics 2019-07-31 Roman Sulzbach , Thorsten Peters , Reinhold Walser

Time reversal (TR) focusing of ultrasound in granular packings is experimentally investigated. Pulsed elastic waves transmitted from a compressional or shear transducer source are measured by a TR mirror, reversed in time and…

Soft Condensed Matter · Physics 2019-12-18 Maxime Harazi , Yougu Yang , Mathias Fink , Arnaud Tourin , Xiaoping Jia

We consider group delay and broadening using two strongly absorbing and widely spaced resonances. We derive relations which show that very large pulse bandwidths coupled with large group delays and small broadening can be achieved. Unlike…

Optics · Physics 2009-11-13 Ryan M. Camacho , Michael V. Pack , John C. Howell

An inverse source reconstruction (ISR) based 3-D near-field (NF) passive radar microwave imaging method utilizing modulated signals is presented. The modulated signals from a non-cooperative transmitter are scattered by the targets of…

Image and Video Processing · Electrical Eng. & Systems 2026-05-06 Quanfeng Wang , Alexander H. Paulus , Thomas F. Eibert

Most ultrasound imaging techniques necessitate the fundamental step of converting temporal signals received from transducer elements into a spatial echogenecity map. This beamforming (BF) step requires the knowledge of speed-of-sound (SoS)…

Medical Physics · Physics 2022-11-22 Can Deniz Bezek , Orcun Goksel

Reverberations are unavoidable in enclosures, resulting in reduced intelligibility for hearing impaired and non native listeners and even for the normal hearing listeners in noisy circumstances. It also degrades the performance of machine…

Audio and Speech Processing · Electrical Eng. & Systems 2022-08-11 Sania Gul , Muhammad Salman Khan , Syed Waqar Shah

Recent advances in powerful pre-trained diffusion models encourage the development of methods to improve the sampling performance under well-trained diffusion models. This paper introduces Diffusion Rejection Sampling (DiffRS), which uses a…

Machine Learning · Computer Science 2024-05-29 Byeonghu Na , Yeongmin Kim , Minsang Park , Donghyeok Shin , Wanmo Kang , Il-Chul Moon

We simulate and discuss novel spatio-temporal propagation effects that relate specifically to pulsed, phase-mismatched second harmonic generation in a negative index material having finite length. Using a generic Drude model for the…

We present designs for the augmentation 'mirror' pulses of large-momentum-transfer atom interferometers that maintain their fidelity as the wavepacket momentum difference is increased. These bi-selective pulses, tailored using optimal…

Atomic Physics · Physics 2020-07-01 Jack Saywell , Max Carey , Ilya Kuprov , Tim Freegarde

We demonstrate a hybrid distributed fiber sensing system for multi-parameter detection. The integration of phase-sensitive optical time domain reflectometry ({\Phi}-OTDR) and Brillouin optical time domain reflectometry (B-OTDR) enables…

Optics · Physics 2016-09-02 Jingdong Zhang , Tao Zhu , Huan Zhou , Yang Li , Min Liu , Wei Huang

The recent proposed orthogonal time frequency space (OTFS) modulation shows signifcant advantages than conventional orthogonal frequency division multiplexing (OFDM) for high mobility wireless communications. However, a challenging problem…

Information Theory · Computer Science 2022-07-25 Xiangxiang Li , Haiyan Wang , Yao Ge , Xiaohong Shen , Yuanyuan Lei

To obtain the most accurate pulse arrival times from radio pulsars, it is necessary to correct or mitigate the effects of the propagation of radio waves through the warm and ionised interstellar medium. We examine both the strength of…

Instrumentation and Methods for Astrophysics · Physics 2016-11-15 R. M. Shannon , J. M. Cordes

We present a mathematical analysis of propagation-induced distortions in the spectro-temporal properties of Fast Radio Bursts (FRBs). Within the Triggered Relativistic Dynamical Model, we derive a centroid-based formulation of the sub-burst…

High Energy Astrophysical Phenomena · Physics 2025-10-21 Aishwarya Kumar , Fereshteh Rajabi , Martin Houde

Several matrix approaches were developed to control light propagation through multiple scattering media under illumination of ultrashort pulses of light. These matrices can be recorded either with spectral or temporal resolution. Thanks to…

Optics · Physics 2018-06-08 Mickael Mounaix , Duc Minh Ta , Sylvain Gigan

Diffusion models are proficient at generating high-quality images. They are however effective only when operating at the resolution used during training. Inference at a scaled resolution leads to repetitive patterns and structural…

Computer Vision and Pattern Recognition · Computer Science 2024-11-28 Haosen Yang , Adrian Bulat , Isma Hadji , Hai X. Pham , Xiatian Zhu , Georgios Tzimiropoulos , Brais Martinez

In portable, 3-D, or ultra-fast ultrasound (US) imaging systems, there is an increasing demand to reconstruct high quality images from limited number of data. However, the existing solutions require either hardware changes or…

Computer Vision and Pattern Recognition · Computer Science 2017-10-31 Yeo Hun Yoon , Jong Chul Ye

Ultrasound attenuation is caused by absorption and scattering in tissue and is thus a function of tissue composition, hence its imaging offers great potential for screening and differential diagnosis. In this paper we propose a novel method…

Signal Processing · Electrical Eng. & Systems 2019-10-15 Richard Rau , Ozan Unal , Dieter Schweizer , Valery Vishnevskiy , Orcun Goksel

In ultrasound (US) imaging, various types of adaptive beamforming techniques have been investigated to improve the resolution and contrast-to-noise ratio of the delay and sum (DAS) beamformers. Unfortunately, the performance of these…

Image and Video Processing · Electrical Eng. & Systems 2020-02-25 Shujaat Khan , Jaeyoung Huh , Jong Chul Ye

The correction of the aberration of transcranial focused ultrasounds is a relevant issue for enhancing various non-invasive medical treatments. Emission through multi-element phased arrays has been the most widely accepted method to reduce…

Medical Physics · Physics 2018-05-28 Marcelino Ferri , JM Bravo , Javier Redondo , JV Sánchez-Pérez

We present a framework for achieving broadband perfect wave transmission in complex systems by optimizing symmetric disordered media via inverse design. We show that leveraging symmetry of complex media reduces the optimization's complexity…