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Context: Some stellar objects exhibit very narrow spectral lines in the visible range additional to their blackbody radiation. Natural lasing has been suggested as a mechanism to explain narrow lines in Wolf-Rayet stars. However, the…

Instrumentation and Methods for Astrophysics · Physics 2017-05-26 Peng Kian Tan , Christian Kurtsiefer

We employ ultra-broadband terahertz-midinfrared probe pulses to characterize the optical response of photoinduced charge-carrier plasmas in high-resistivity silicon in a reflection geometry, over a wide range of excitation densities…

Materials Science · Physics 2015-02-11 Fanqi Meng , Mark D. Thomson , Bo E. Sernelius , Michael Jörger , Hartmut G. Roskos

We propose a dot-tracking methodology for processing Background Oriented Schlieren (BOS) images. The method significantly improves the accuracy, precision and spatial resolution compared to conventional cross-correlation algorithms. Our…

Fluid Dynamics · Physics 2019-10-23 Lalit K. Rajendran , Sally P. M. Bane , Pavlos P. Vlachos

We experimentally study spatial fluctuations of the local density of states (LDOS) inside three-dimensional random photonic media. The LDOS is probed at many positions inside the random photonic media by measuring emission rates of a large…

Optics · Physics 2010-07-06 M. D. Birowosuto , S. E. Skipetrov , W. L. Vos , A. P. Mosk

Light scattering imposes a major obstacle for imaging objects seated deeply in turbid media, such as biological tissues and foggy air. Diffuse optical tomography (DOT) tackles scattering by volumetrically recovering the optical absorbance…

Electronic density of states (DOS) is a key factor in condensed matter physics and material science that determines the properties of metals. First-principles density-functional theory (DFT) calculations have typically been used to obtain…

Materials Science · Physics 2019-04-12 Byung Chul Yeo , Donghun Kim , Chansoo Kim , Sang Soo Han

Mode separation, namely how sharply a distribution fragments into barrier-separated clusters, is a fundamental geometric property of densities, difficult to quantify in high dimensions. It is structurally distinct from dispersion, yet…

Machine Learning · Statistics 2026-05-12 Shaul Tolkovsky , Ori Meidler , Or Zuk

A correlation optical time-domain reflectometry (COTDR) method is presented, which measures the propagation delay with an accuracy of a few picoseconds. This accuracy is achieved using a test signal data rate of 10 Gbit/s and employing…

Optics · Physics 2022-02-24 Florian Azendorf , Annika Dochhan , Michael H. Eiselt

Optical fibres constitute an exceptional sensing platform. However, standard fibres present an inherent sensing challenge: they confine light by design to an inner core. Consequently, nearly all distributed fibre sensors are restricted to…

Optics · Physics 2018-11-21 Gil Bashan , Hilel Hagai Diamandi , Yosef London , Eyal Preter , Avi Zadok

Non-invasive detection of objects embedded inside an optically scattering medium is essential for numerous applications in engineering and sciences. However, in most applications light at visible or near-infrared wavebands is scattered by…

The previous research proves that the random laser emission reflects not only the scattering properties but also the absorption properties. The random laser is therefore considered a potential tool for optical properties sensing. Although…

Optics · Physics 2024-07-15 Dongqin Ni , Florian Klämpfl , Michael Schmidt , Martin Hohmann

The density of states (DOS) is a spectral property of materials, which provides fundamental insights on various characteristics of materials. In this paper, we propose a model to predict the DOS by reflecting the nature of DOS: DOS…

Machine Learning · Computer Science 2023-04-11 Namkyeong Lee , Heewoong Noh , Sungwon Kim , Dongmin Hyun , Gyoung S. Na , Chanyoung Park

Dynamic light scattering techniques are routinely used for numerous industrial and research applications, because they can give access to the motion spectrum of micro- and nano-objects, and therefore to particle sizes or visco-elastic…

Optics · Physics 2022-09-22 Guillaume Graciani , John T. King , Francois Amblard

We propose DOPS, a fast single-stage 3D object detection method for LIDAR data. Previous methods often make domain-specific design decisions, for example projecting points into a bird-eye view image in autonomous driving scenarios. In…

Computer Vision and Pattern Recognition · Computer Science 2020-04-08 Mahyar Najibi , Guangda Lai , Abhijit Kundu , Zhichao Lu , Vivek Rathod , Thomas Funkhouser , Caroline Pantofaru , David Ross , Larry S. Davis , Alireza Fathi

Score-based diffusion models are a recently developed framework for posterior sampling in Bayesian inverse problems with a state-of-the-art performance for severely ill-posed problems by leveraging a powerful prior distribution learned from…

Density correlations unambiguously reveal the quantum nature of matter. Here, we study correlations between measurements of density in cold-atom clouds at different times at one position, and also at two separated positions. We take into…

Quantum Gases · Physics 2015-03-16 M. Kohnen , R. A. Nyman

Spectral diffusion is a result of random spectral jumps of a narrow line as a result of a fluctuating environment. It is an important issue in spectroscopy, because the observed spectral broadening prevents access to the intrinsic line…

Photoacoustic Remote Sensing (PARS) microscopy is an emerging label-free optical absorption imaging modality. PARS operates by capturing nanosecond-scale optical perturbations generated by photoacoustic pressures. These time-domain (TD)…

Medical Physics · Physics 2022-08-17 Nicholas Pellegrino , Benjamin R. Ecclestone , Paul Fieguth , Parsin Haji Reza

We describe a new method for the rapid determination of the mass of particles confined in a free-space optical dipole-force trap. The technique relies on direct imaging of drop-and-restore experiments without the need for a vacuum…

In absence of a lens to form an image, incoherent or partially coherent light scattering off an obstructive or reflective object forms a broad intensity distribution in the far field with only feeble spatial features. We show here that…