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We propose a novel scheme for asymmetric light diffraction of a weak probe field into a one-dimensional (1D) and two-dimensional (2D) lattice occupied with cold atoms. The atoms are driven into the double lambda-type configuration by a…

Quantum Physics · Physics 2020-10-12 Ali Akbar Naeimi , Elham Darabi , Ali Mortezapour , Ghasem Naeimi

The liquid, plastic crystalline and ordered crystalline phases of CBr$_4$ were studied using neutron powder diffraction. The measured total scattering differential cross-sections were modelled by Reverse Monte Carlo simulation techniques…

Chemical Physics · Physics 2010-04-06 László Temleitner , László Pusztai

Interfering liquid surface waves are generated by electrically driven vertical oscillations of two or more equispaced pins immersed in a liquid (water). The corresponding intensity distribution, resulting from diffraction of monochromatic…

Optics · Physics 2009-11-10 Tarun Kr. Barik , Anushree Roy , Sayan Kar

The human tear film (TF) is thin multilayer fluid film that is critical for clear vision and ocular surface health. Its dynamics are strongly affected by a floating lipid layer and, in health, that layer slows evaporation and helps create a…

Fluid Dynamics · Physics 2024-04-23 M. J. Taranchuk , R. J. Braun

We describe propagation of light in a gas with periodic density modulation, demonstrating photonic-crystal-like refraction with negative refraction angles. We address the role of poorly defined boundaries and damping, and derive an optical…

Optics · Physics 2015-03-11 Marina Litinskaya , Evgeny A. Shapiro

Geometrically decorated two-dimensional (2D) discrete surfaces can be more effective than conventional smooth reflectors in managing wave radiation. Constructive non-specular wave scattering permits the scattering angle to be other than…

For the first time the electrohydrodynamic convection (EHC) of nematic liquid crystals is studied via fully nonlinear simulation. As a system of rich pattern-formation the EHC is mostly studied with negative nematic liquid crystals…

Soft Condensed Matter · Physics 2016-12-28 Kuang-Wu Lee , Thorsten Pöschel

We study spatial optical solitons in a one-dimensional nonlinear photonic crystal created by an array of thin-film nonlinear waveguides, the so-called Dirac-comb nonlinear lattice. We analyze modulational instability of the extended…

Pattern Formation and Solitons · Physics 2007-05-23 Andrey A. Sukhorukov , Yuri S. Kivshar

This paper proposes a non-computational method of counteracting the effect of image degradation introduced by the diffraction phenomenon in lensless microscopy. All the optical images (whether focused by lenses or not) are diffraction…

Optics · Physics 2021-04-08 Sanjeev Kumar , Manjunatha Mahadevappa , Pranab Kumar Dutta

Coherent nonlinear optical micro-spectroscopy is a frequently used tool in modern material science, as it is sensitive to many different local observables, which comprise, among others, crystal symmetry and vibrational properties. The…

Optics · Physics 2023-04-12 Kai J. Spychala , Zeeshan H. Amber , Lukas M. Eng , Michael Rüsing

We report a general description of quasi-phase-matched parametric process in nonlinear photonic crystals (NLPC) by extending the conventional X-ray diffraction theory in solids. Under the virtual wave approximation, phase-matching resonance…

Optics · Physics 2015-05-13 H. C. Guo , Y. Q. Qin , G. J. You , W. M. Liu , S. H. Tang

Optical diffraction tomography is an indispensable tool for studying objects in three-dimensions due to its ability to accurately reconstruct scattering objects. Until now this technique has been limited to coherent light because spatial…

The properties of liquid crystals can be modelled using an order parameter which describes the variability of the local orientation of rod-like molecules. Defects in the director field can arise due to external factors such as applied…

Numerical Analysis · Mathematics 2019-10-08 Craig S. MacDonald , John A. Mackenzie , Alison Ramage

We demonstrate first- and second-order spatial differentiation of an optical beam transverse profile using thin suspended subwavelength gratings. Highly reflective one-dimensional gratings are patterned on suspended 200 nm-thick silicon…

We study stability and distortions of liquid crystal nematic order in a cell with a random heterogeneous substrate. Modeling this system as a bulk xy model with quenched disorder confined to a surface, we find that nematic order is…

Soft Condensed Matter · Physics 2010-05-05 Quan Zhang , Leo Radzihovsky

Light traveling through a liquid crystal with disclinations perceives a geometrical background which causes lensing effects similar to the ones predicted for cosmic objects like global monopoles and cosmic strings. In this article we…

Soft Condensed Matter · Physics 2009-11-11 Caio Satiro , Fernando Moraes

Slow-light enhanced optical detection in liquid-infiltrated photonic crystals is theoretically studied. Using a scattering-matrix approach and the Wigner-Smith delay time concept, we show that optical absorbance benefits both from…

Optics · Physics 2008-02-02 M. E. V. Pedersen , L. S. Rishoj , H. Steffensen , S. Xiao , N. A. Mortensen

The optical polarimetry technique is used to explore molecular ordering of nematic liquid crystals 5FPFFPP3 embedded in parallel cylindrical channels of alumina membranes with pore walls covered by a SE-1211 polymer film enhancing normal…

Soft Condensed Matter · Physics 2018-06-19 A. V. Kityk , P. Huber , K. Sentker , A. Andrushchak , P. Kula , W. Piecek , R. Wielgosz , O. Kityk , P. Goering , M. Lelonek

We study the effect of spatial dispersion of crystal modes on optical properties such as the reflectivity $R$. As an example for isotropic media, we investigate the simplest model for phonons in ionic crystals and compare with previous…

Optics · Physics 2009-11-10 I. Kaelin , Ch. Helm , G. Blatter

We show theoretically that thermomechanical effects in dye-doped nematic liquid crystals when illuminated by laser beams, can become important and lead to molecular reorientation at intensities substantially lower than that needed for…

Fluid Dynamics · Physics 2007-06-13 Dmitry O. Krimer , Stefania Residori