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We design an optical feedback network making use of machine learning techniques and demonstrate via simulations its ability to correct for the effects of turbulent propagation on optical modes. This artificial neural network scheme only…

Signal Processing · Electrical Eng. & Systems 2018-06-22 Sanjaya Lohani , Ryan T. Glasser

Studying transition to a highly disordered state of turbulence from a linearly stable coherent laminar state is conceptually and technically challenging and immensely important, e.g. all pipe and channel flows are of that type. In optics,…

Studying the coherence of an optical field is typically compartmentalized with respect to its different optical degrees of freedom (DoFs) -- spatial, temporal, and polarization. Although this traditional approach succeeds when the DoFs are…

Proposed, justified and tested measuring of beam spatial coherence, based on the detection of an interference visibility of the equal to intensity of beam replicas emerging under reflection from the rotated plane-parallel plate. The method…

Optics · Physics 2015-10-20 E. A. Tikhonov , A. K. Lyamets

Airy beams are known for displaying shape invariance and self-acceleration along the transverse direction while they propagate forwards. Although these properties could be associated with the beam coherence, it has been revealed that they…

Quantum Physics · Physics 2022-11-17 R. Martínez-Herrero , A. S. Sanz

When a resonant laser sent on an optically thick cold atomic cloud is abruptly switched off, a coherent flash of light is emitted in the forward direction. This transient phenomenon is observed due to the highly resonant character of the…

Atomic Physics · Physics 2015-05-27 Maryvonne Chalony , Romain Pierrat , Dominique Delande , David Wilkowski

We have experimentally confirmed the presence of long-memory correlations in the wandering of a thin Gaussian laser beam over a screen after propagating through a turbulent medium. A laboratory-controlled experiment was conducted in which…

Optics · Physics 2015-07-07 Luciano Zunino , Damián Gulich , Gustavo Funes , Darío G. Pérez

We have constructed an automated learning apparatus to control quantum systems. By directing intense shaped ultrafast laser pulses into a variety of samples and using a measurement of the system as a feedback signal, we are able to reshape…

Quantum Physics · Physics 2009-11-06 B. J. Pearson , J. L. White , T. C. Weinacht , P. H. Bucksbaum

To effectively apply passive speckle reduction methods, it is essential to use an illumination system that maximally exploits the non-ideal temporal coherence and angular diversity (spatial coherence reduction) of laser light. This study…

Optics · Physics 2025-04-28 A. Lapchuk , O. Prygun , D. Manko , I. Gorbov , Y. Morozov

Many adaptive optics systems operate by measuring the distortion of the wavefront in one wavelength range and performing the scientific observations in a second, different wavelength range. One common technique is to measure wavefront…

Astrophysics · Physics 2009-11-07 Henry G. Roe

We demonstrate experimentally and numerically that the application of a partially coherent beam (PCB) in combination with time averaging leads to a significant reduction in the scintillation index. We use a simplified experimental approach…

We investigate the nonlinear Compton photon source for upcoming laser-particle experiments in the collision scenario of high-energy electron beams and relativistic laser pulses. The stronger laser field could not only improve the scattering…

High Energy Physics - Phenomenology · Physics 2025-05-23 Yu Xin , Zu-dong Zhao , Suo Tang

We present the experimental realization of a laser system for ground to satellite optical Doppler ranging at the atmospheric turbulence limit. Such a system needs to display good frequency stability (a few parts in 10^{-14}) whilst allowing…

Optics · Physics 2013-11-12 Nicola Chiodo , Khelifa Djerroud , Ouali Acef , Andre Clairon , Peter Wolf

Although coherent light is usually required for the self-organization of regular spatial patterns from optical beams, we show that peculiar light matter interaction can break this evidence. In the traditional method to record laser-induced…

Using a master-equation approach for the description of coherent and incoherent dynamics in `artificial atoms and molecules', we present a theoretical analysis of situations where intense laser fields lead to pronounced renormalizations of…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Ulrich Hohenester , Filippo Troiani , Elisa Molinari

A laser diffraction experiment was conducted to study light propagation in air. The experiment is easy to reproduce and it is based on simple optical principles. Two optical sensors (segmented photo-diodes) are used for measuring the…

Astrophysics · Physics 2007-05-23 C. E. Navia , C. R. A. Augusto , D. F. Franceschini , M. B. Robba , K. H. Tsui

We demonstrate a strong coherent backward wave oscillation using forward propagating fields only. This is achieved by applying laser fields to an ultra-dispersive medium with proper chosen detunings to excite a molecular vibrational…

Quantum Physics · Physics 2009-11-13 Yuri V. Rostovtsev , Zoe-Elizabeth Sariyanni , Marlan O. Scully

Coherent backscattering is a coherence effect in the propagation of waves through disordered media involving two or more scattering events. Here, we report on the observation of coherent backscattering from individual atoms and their mirror…

A method for active control of the spatial profile of a laser beam using adaptive thermal lensing is described. A segmented electrical heater was used to generate thermal gradients across a transmissive optical element, resulting in a…

A theory is presented (and supported by numerical simulations) for phase-coherent reflection of light by a disordered medium which either absorbs or amplifies radiation. The distribution of reflection eigenvalues is shown to be the Laguerre…

Condensed Matter · Physics 2007-05-23 C. W. J. Beenakker , J. C. J. Paasschens , P. W. Brouwer