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Measuring the field of visible light with high spatial resolution has been challenging, as many established methods only detect a focus-averaged signal. Here, we introduce a near-field method for optical field sampling that overcomes that…

Nowadays powerful X-ray sources like synchrotrons and free-electron lasers are considered as ultimate tools for probing microscopic properties in materials. However, the correct interpretation of such experiments requires a good…

Materials Science · Physics 2018-02-28 B. Ruta , F. Zontone , Y. Chushkin , G. Baldi , G. Pintori , G. Monaco , B. Rufflé , W. Kob

The versatility of optics enables the design of a wide range of elegant beam instrumentation. Multiple properties of particle beams can be precisely measured by various optical techniques, which include: direct sampling of optical radiation…

Accelerator Physics · Physics 2020-07-23 Stephen Gibson

Spatial Frequency Domain Imaging can map tissue scattering and absorption properties over a wide field of view, making it useful for clinical applications such as wound assessment and surgical guidance. This technique has previously…

Biological Physics · Physics 2021-02-24 Mason T. Chen , Melina Papadakis , Nicholas J. Durr

Dark-field X-ray imaging is a novel modality which visualises scattering from unresolved microstructure. Most dark-field imaging techniques rely on crystals or structured illumination, but recent work has shown that dark-field effects are…

Medical Physics · Physics 2024-09-04 Jannis N. Ahlers , Konstantin M. Pavlov , Marcus J. Kitchen , Kaye S. Morgan

Random feature approximation is arguably one of the most widely used techniques for kernel methods in large-scale learning algorithms. In this work, we analyze the generalization properties of random feature methods, extending previous…

Machine Learning · Statistics 2025-06-23 Mike Nguyen , Nicole Mücke

Beam shaping - the ability to engineer the phase and the amplitude of massive and massless particles - has long interested scientists working on communication, imaging and the foundations of quantum mechanics. In light optics, the shaping…

Scanning near-field optical microscopy is one of the most effective techniques for spectroscopy of nanoscale systems. However, inferring optical constants from the measured near-field signal can be challenging because of a complicated and…

Optics · Physics 2023-04-19 Yueqi Zhao , Xinzhong Chen , Ziheng Yao , Mengkun Liu , Michael M. Fogler

We consider different approaches to simulate a modern X-ray beamline. Several methodologies with increasing complexity are applied to discuss the relevant parameters that quantify the beamline performance. Parameters such as flux,…

When a coherent laser beam impinges on a random sample (e.g. a colloidal suspension), the scattered light exhibits characteristic speckles. If the temporal coherence of the light source is too short, then the speckles disappear, along with…

Optics · Physics 2011-12-13 D. Brogioli , D. Salerno , F. Croccolo , R. Ziano , F. Mantegazza

Nonlinear processes lie at the heart of many technologies such as frequency converters and entangled photon sources. Historically, observation and manipulation of these processes, for instance through nanostructures, has been limited to…

We develop X-ray Multi-modal Intrinsic-Speckle-Tracking (MIST), a form of X-ray speckle-tracking that is able to recover both the position-dependent phase shift and the position-dependent small-angle X-ray scattering (SAXS) signal of a…

Image and Video Processing · Electrical Eng. & Systems 2021-11-16 Konstantin M. Pavlov , David M. Paganin , Heyang Li , Sebastien Berujon , Hélène Rougé-Labriet , Emmanuel Brun

With the introduction of x-ray free electron laser sources around the world, new scientific approaches for visualizing matter at fundamental length and time-scales have become possible. As it relates to magnetism and "magnetic-type"…

Structured light harnessing multiple degrees of freedom has become a powerful approach to use complex states of light in fundamental studies and applications. Here, we investigate the light field of an ultrafast laser beam with a…

X-ray dark-field imaging enables a spatially-resolved visualization of ultra-small-angle X-ray scattering. Using phantom measurements, we demonstrate that a material's effective dark-field signal may be reduced by modification of the…

The novel concept of near-field velocity sensing is proposed. In contrast to far-field velocity sensing, near-field velocity sensing enables the simultaneous estimation of both radial and transverse velocities of a moving target. A…

Information Theory · Computer Science 2024-09-24 Zhaolin Wang , Xidong Mu , Yuanwei Liu

We present a general theory of thermalization of light in multimode optical fibers, including optical beams with nonzero orbital angular momentum or vortex beams. A generalized Rayleigh-Jeans distribution of asymptotic mode composition is…

Correlated states of light, both classical and quantum, can find useful applications in the implementation of several imaging techniques. Among the employed sources, pseudo-thermal states, generated by the passage of a laser beam through a…

Quantum Physics · Physics 2024-03-18 Silvia Cassina , Gabriele Cenedese , Alessia Allevi , Maria Bondani

Due to the complex of mixed spectral point spread function within memory effect range, it is unreliable and slow to use speckle correlation technology for non-invasive imaging through scattering medium under broadband illumination. The…

We study efficiency of intensity-based dynamic speckle method for characterization of dynamic events which occur at variable rate in time within the temporal averaging interval. We checked ability of the method to describe the speed…