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Photometric instruments operating at far infrared to millimetre wavelengths often have broad spectral passbands (central wavelength/bandwidth ~ 3 or less), especially those operating in space. A broad passband can result in significant…

In long-baseline interferometry, bandwidth smearing of an extended source occurs at finite bandwidth when its different components produce interference packets that only partially overlap. In this case, traditional model fitting or image…

Instrumentation and Methods for Astrophysics · Physics 2013-08-07 Régis Lachaume , Jean-Philippe Berger

Space-time (ST) wave packets are coherent pulsed beams that propagate diffraction-free and dispersion-free by virtue of tight correlations introduced between their spatial and temporal spectral degrees of freedom. Less is known of the…

Wavefront shaping allows focusing light through or inside strongly scattering media, but the background intensity also increases due to long-range correlations, reducing the target's contrast. By manipulating non-local intensity…

We investigate the influence of the phase-front curvature of an input light beam on the transverse localization of light by choosing an evanescently coupled disordered one-dimensional semi-infinite waveguide lattice as an example. Our…

Optics · Physics 2015-06-04 S Ghosh , B P Pal , R K Varshney , G P Agrawal

X-ray ptychography is a cutting edge imaging technique providing ultra-high spatial resolutions. In ptychography, phase retrieval, i.e., the recovery of a complex valued signal from intensity-only measurements, is enabled by exploiting a…

Image and Video Processing · Electrical Eng. & Systems 2022-09-14 Felix Wittwer , Peter Modregger

Owing to the advent of large area photometric surveys, the possibility to use broad band photometric data, instead of spectra, to measure the size of the broad line region of active galactic nuclei, has raised a large interest. We describe…

Astrophysics of Galaxies · Physics 2014-11-11 D. Sluse , M. Tewes

All optical systems, which involve the collimation of a reflected, transmitted or scattered wave subsequent to tight focusing, are subject to two kinds of deviations. One is the wavefront curvature due to inaccurate focal placement of the…

Optics · Physics 2024-06-10 Nitish Kumar , Anirban Debnath , Nirmal K. Viswanathan

The presence of a scattering medium in the imaging path between an object and an observer is known to severely limit the visual acuity of the imaging system. We present an approach to circumvent the deleterious effects of scattering, by…

Artificial intelligence (AI) has rapidly evolved into a critical technology; however, electrical hardware struggles to keep pace with the exponential growth of AI models. Free space optical hardware provides alternative approaches for…

Optics · Physics 2025-10-07 Xue Dong , Kai Lion , Fei Xia , YoonSeok Baek , Ziao Wang , Niao He , Sylvain Gigan

Phase-sensitive coherent imaging exploits changes in the phases of backscattered light to observe tiny alterations of scattering structures or variations of the refractive index. But moving scatterers or a fluctuating refractive index…

Collective coherent light scattering by polarizable particles creates surprisingly strong, long range inter-particle forces originating from interference of the light scattered by different particles. While for monochromatic laser beams…

Optics · Physics 2016-11-23 Daniela Holzmann , Helmut Ritsch

Previous studies have shown that the frequency content of an illumination affects the convergence rate and reconstruction quality of ptychographic reconstructions. In this numerical study, we demonstrate that structuring a large…

Image and Video Processing · Electrical Eng. & Systems 2020-04-07 Daniel J. Ching , Selin Aslan , Viktor Nikitin , Michael J. Wojcik , Doga Gursoy

Ptychography, a form of Coherent Diffractive Imaging, is used with short wavelengths (e.g. X-rays, electron beams) to achieve high-resolution image reconstructions. One of the limiting factors for the reconstruction quality is the accurate…

Image and Video Processing · Electrical Eng. & Systems 2018-04-02 P. Dwivedi , A. P. Konijnenberg , S. F. Pereira , H. P. Urbach

Ptychography is a technique widely used in microscopy for achieving high-resolution imaging. This method relies on computational processing of images gathered from diffraction patterns produced by several partial illuminations of a sample.…

Optics · Physics 2022-09-07 Fabiola Salinas , M. A. Solís-Prosser

Noncoherent communication systems have regained interest due to the growing demand for high-mobility and low-latency applications. Most existing studies using large antenna arrays rely on the far-field approximation, which assumes locally…

Signal Processing · Electrical Eng. & Systems 2025-05-26 Aniol Martí , Luca Sanguinetti , Meritxell Lamarca , Jaume Riba

Speckle patterns are inherent features of coherent light propagation through complex media. As a result of interference, they are sensitive to multiple experimental parameters such as the configuration of disorder or the propagating…

Microscopy and optical imaging are drastically limited by the inhomogeneities encountered by the light while propagating from the object of interest to the detection system. In this context, adaptive optics and wavefront manipulation are…

Optics · Physics 2017-01-23 Diego Di Battista

Spectrographs nominally contain a degree of quasi-static optical aberrations resulting from the quality of manufactured component surfaces, imperfect alignment, design residuals, thermal effects, and other other associated phenomena…

Instrumentation and Methods for Astrophysics · Physics 2021-07-28 Eric B. Bechter , Andrew J. Bechter , Justin R. Crepp , Jonathan Crass

The effect of the laser linewidth on the resonance fluorescence spectrum of a two-level atom is revisited. The novel spectral features, such as hole-burning and dispersive profiles at line centre of the fluorescence spectrum are predicted…

Quantum Physics · Physics 2009-10-31 Peng Zhou , Mao-Fa Fang , Qing-Ping Zhou , Gao-Xiang Li