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Soltaninezhad M, Bavali A, Nazifinia Z, Soleimani V. Optical anisotropy measurement in normal and cancerous tissues: backscattering technique. BIOMEDICAL OPTICS EXPRESS 2020; 11:2996-3008. [PMID: 32637237 PMCID: PMC7316004 DOI: 10.1364/boe.393079] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 04/23/2020] [Accepted: 05/04/2020] [Indexed: 05/30/2023]
Abstract
Investigating the deformation of tissue architecture is one of the most important clinical methods for cancer diagnosis. Optical methods are now widely developed for rapid, precise, and real-time assessment of these alterations at the microscopic scale. One of the proposed methods is enhanced backscattering (EBS) technique that allows in-vivo measurement of the optical scattering characteristics. Here, EBS technique is employed to evaluate the optical anisotropy of human epithelial tissues as a measure to distinguish between normal and cancerous one. Orientation dependence of the mean scattering length is assessed in healthy and cancerous tissues of five different human organs i. e. uterus, bladder, colon, kidney, and liver. Helicity preserving channel and rotating ground glass diffuser are utilized to eliminate the polarization induced anisotropy and the background speckle noises respectively. Analysis of the backscattering cones recorded by a high-resolution CCD camera reveals the modification of the strength and degree of optical anisotropy in different tissues during cancer progression. Pathology data affirm the correlation between the experimental results and the morphological alteration of the epithelial cells in each carcinoma type. In general, tissues with fibrous constructional cells are subject to a decrease in anisotropy due to cancer, whereas those with cuboidal cells experience an increase in anisotropy. This complementary information enhances the potency of the EBS technique as a fast, non-destructive, and easily accessible tool for real-time tissue diagnosis.
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Affiliation(s)
- Mohammad Soltaninezhad
- Department of Energy Engineering and Physics, Amirkabir University of Technology (Tehran Polytechnic), Iran
| | - Ali Bavali
- Department of Energy Engineering and Physics, Amirkabir University of Technology (Tehran Polytechnic), Iran
| | - Ziba Nazifinia
- Department of Energy Engineering and Physics, Amirkabir University of Technology (Tehran Polytechnic), Iran
| | - Vahid Soleimani
- Department of Cancer Institute, Imam Khomeini Medical Centre, Tehran, Iran
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2
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Li J, Chen F, Chang L. Correlation between intensity fluctuations of electromagnetic waves scattered from a spatially quasi-homogeneous, anisotropic medium. OPTICS EXPRESS 2016; 24:24274-24286. [PMID: 27828159 DOI: 10.1364/oe.24.024274] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Within the validity of the first-order Born approximation, expressions are derived for the correlation between intensity fluctuations (CIF) of an electromagnetic plane wave scattered from a spatially quasi-homogeneous (QH), anisotropic medium. Upon establishing the correlation matrix of the scattering potential of the medium, we show that the CIF is the summation of Fourier transforms of the strengths and normalized correlation coefficients (NCCs) of the scattering potential matrix. Numerical results reveal that the CIF is susceptible to the effective width and correlation length of the medium, and degree of polarization of the incident electromagnetic wave. Our study not only extends the current knowledge of the CIF of a scattered field but also provides an important reference to the study of high-order intensity correlations of light scattered from a spatially anisotropic medium.
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3
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Alerstam E. Anisotropic diffusive transport: connecting microscopic scattering and macroscopic transport properties. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:063202. [PMID: 25019904 DOI: 10.1103/physreve.89.063202] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Indexed: 06/03/2023]
Abstract
This work concerns the modeling of radiative transfer in anisotropic turbid media using diffusion theory. A theory for the relationship between microscopic scattering properties (i.e., an arbitrary differential scattering cross-section) and the macroscopic diffusion tensor, in the limit of independent scatterers, is presented. The theory is accompanied by a numerical method capable of performing the calculations. In addition, a boundary condition appropriate for modeling systems with anisotropic radiance is derived. It is shown that anisotropic diffusion theory, when based on these developments, indeed can describe radiative transfer in anisotropic turbid media. More specifically, it is reported that solutions to the anisotropic diffusion equation are in excellent agreement with Monte Carlo simulations, both in steady-state and time-domain. This stands in contrast to previous work on the topic, where inadequate boundary conditions and/or incorrect relations between microscopic scattering properties and the diffusion tensor have caused disagreement between simulations and diffusion theory. The present work thus falsify previous claims that anisotropic diffusion theory cannot describe anisotropic radiative transfer, and instead open for accurate quantitative diffusion-based modeling of anisotropic turbid materials.
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Affiliation(s)
- Erik Alerstam
- Division of Atomic Physics, Department of Physics, Lund University, P.O. Box 118, 221 00 Lund, Sweden
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4
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Simon E, Krauter P, Kienle A. Time-resolved measurements of the optical properties of fibrous media using the anisotropic diffusion equation. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:075006. [PMID: 25055055 DOI: 10.1117/1.jbo.19.7.075006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 06/25/2014] [Indexed: 06/03/2023]
Abstract
Transmittance and reflectance from spruce wood and bovine ligamentum nuchae as two different fibrous media are examined by time-of-flight spectroscopy for varying source detector separations and several orientations of the fibers in the sample. The anisotropic diffusion theory is used to obtain the absorption coefficient and the diffusion coefficients parallel and perpendicular to the fibers. The results are compared to those obtained with the isotropic diffusion theory. It is shown that for increasing source detector separations, the retrieved optical properties change as expected from Monte Carlo simulations performed in a previous study. This confirms that the anisotropic diffusion theory yields useful results for certain experimental conditions.
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5
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Kienle A, Foschum F, Hohmann A. Light propagation in structural anisotropic media in the steady-state and time domains. Phys Med Biol 2013; 58:6205-23. [DOI: 10.1088/0031-9155/58/17/6205] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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6
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Sadjadi Z, Miri M. Diffusive transport of light in two-dimensional granular materials. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 84:051305. [PMID: 22181409 DOI: 10.1103/physreve.84.051305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Indexed: 05/31/2023]
Abstract
We study photon diffusion in a two-dimensional random packing of monodisperse disks as a simple model of granular material. We apply ray optics approximation to set up a persistent random walk for the photons. We employ Fresnel's intensity reflectance with its rich dependence on the incidence angle and polarization state of the light. We present an analytic expression for the transport-mean-free path l* in terms of the refractive indices of grains and host medium, grain radius, and packing fraction. We perform numerical simulations to examine our analytical result.
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Affiliation(s)
- Zeinab Sadjadi
- Theoretische Physik, Universität des Saarlandes, Saarbrücken, Germany
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7
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Shuaib A, Yao G. Equi-intensity distribution of optical reflectance in a fibrous turbid medium. APPLIED OPTICS 2010; 49:838-844. [PMID: 20154751 DOI: 10.1364/ao.49.000838] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Light propagation in a fibrous anisotropic scattering medium is quite different from that in an isotropic medium. Both the anisotropic diffuse equation (ADE) and the continuous time random walk (CTRW) theory predict that the equi-intensity profiles of the surface reflectance have an elliptical shape in a fibrous turbid medium. In this study, we simulated the spatially resolved surface reflectance in a fibrous sample using a Monte Carlo model. A parametric equation was used to quantitatively characterize the geometric profiles of the reflectance patterns. The results indicated that the equi-intensity profiles of surface reflectance had elliptical shapes only when evaluated at distances far away from the incident point. The length ratio of the two orthogonal axes of the ellipse was not affected by the sample optical properties when the ratio of reduced scattering coefficients along the two axes is the same. But the relationship between the aforementioned two ratios was different from the predication of ADE theory. Only for fibers of small sizes did the fitted axes ratios approach the values predicted from the ADE theory.
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Affiliation(s)
- Ali Shuaib
- Department of Biological Engineering, University of Missouri, Columbia, Missouri 65211, USA
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8
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Johnson PM, Lagendijk A. Optical anisotropic diffusion: new model systems and theoretical modeling. JOURNAL OF BIOMEDICAL OPTICS 2009; 14:054036. [PMID: 19895137 DOI: 10.1117/1.3253332] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We have developed several new experimental model systems that demonstrate anisotropic diffusion of light. These systems, consisting of aligned fibers, stretched plastic foam, and stretched plastic frit, have relatively simple microstructures and are easily sliced, making them ideal for testing theoretical models of diffusion. We demonstrate that the solution to the diffusion equation for arbitrary orientation of the diffusion tensor is consistent with experimental measurements. We also show that simple models of microstructure, based on cylindrical and planar scatterers, are consistent with the experimental results. These models provide simple analytical expressions for predicting the degree of alignment of the scatterers from diffuse transmission measurements. The combination of experimental results and theoretical support demonstrates both the power and the limitations of the diffusion model for providing information about microstructure via simple experiments and modeling.
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Affiliation(s)
- Patrick M Johnson
- FOM Institute for Atomic and Molecular Physics (AMOLF), Science Park 113, Amsterdam 1098 XG, The Netherlands.
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Ferjani S, De Luca A, Barna V, Versace C, Strangi G. Thermo-recurrent nematic random laser. OPTICS EXPRESS 2009; 17:2042-2047. [PMID: 19189035 DOI: 10.1364/oe.17.002042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
This experimental work is aimed to investigate the thermal behavior of random laser action in dye doped nematic liquid crystals. The study evidenced an important temperature dependence of the random lasing characteristics in the nematic phase and in close proximity of the nematicisotropic (N-I) phase transition. A lowering of the laser emission intensity as the temperature increases is strictly related to the shift of the lasing threshold as function of the temperature even though the pump energy is kept fixed. The optical losses increasing owing to the thermal fluctuation enhanced scattering drive the input-output smoother behavior until the system stops to lase, because below threshold. The unexpected reoccurrence of random lasing at higher temperature, in proximity of N-I transition is found to be related to a different scattering mechanism, the micro-droplets nucleation and critical opalescence.
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Affiliation(s)
- S Ferjani
- LICRYL CNR-INFM and Center of Excellence CEMIF.CAL, Department of Physics, University of Calabria, Rende (CS), Italy
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10
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Sadjadi Z, Miri M, Shaebani MR, Nakhaee S. Diffusive transport of light in a two-dimensional disordered packing of disks: analytical approach to transport mean free path. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 78:031121. [PMID: 18851007 DOI: 10.1103/physreve.78.031121] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Revised: 08/28/2008] [Indexed: 05/26/2023]
Abstract
We study photon diffusion in a two-dimensional random packing of monodisperse disks as a simple model of granular media and wet foams. We assume that the intensity reflectance of disks is a constant r . We present an analytic expression for the transport mean free path l;{*} in terms of the velocity of light in the disks and host medium, radius R and packing fraction of the disks, and the intensity reflectance. For glass beads immersed in air or water, we estimate transport mean free paths about half the experimental ones. For air bubbles immersed in water, l;{*}R is a linear function of 1epsilon , where epsilon is the liquid volume fraction of the model wet foam. This throws light on the empirical law of Vera [Appl. Opt. 40, 4210 (2001)] and promotes more realistic models.
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Affiliation(s)
- Zeinab Sadjadi
- Institute for Advanced Studies in Basic Sciences (IASBS), P.O. Box 45195-1159, Zanjan 45195, Iran
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11
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Johnson PM, Faez S, Lagendijk A. Full characterization of anisotropic diffuse light. OPTICS EXPRESS 2008; 16:7435-7446. [PMID: 18545448 DOI: 10.1364/oe.16.007435] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We demonstrate a method for fully characterizing diffuse transport of light in a statistically anisotropic opaque material. Our technique provides a simple means of determining all parameters governing anisotropic diffusion. Anisotropy in the diffusion constant, the mean free path, and the extrapolation length are, for the first time, determined independently. These results show that the anisotropic diffusion model is effective for modeling transport in anisotropic samples, providing that the light is allowed to travel several times the transport mean free path from the source.
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Affiliation(s)
- P M Johnson
- FOM Institute for Atomic and Molecular Physics AMOLF, Kruislaan 407 Amsterdam, The Netherlands.
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12
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Sadjadi Z, Miri M, Stark H. Diffusive transport of light in three-dimensional disordered Voronoi structures. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 77:051109. [PMID: 18643028 DOI: 10.1103/physreve.77.051109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Indexed: 05/26/2023]
Abstract
The origin of diffusive transport of light in dry foams is still under debate. In this paper, we consider the random walks of photons as they are reflected or transmitted by liquid films according to the rules of ray optics. The foams are approximately modeled by three-dimensional Voronoi tessellations with varying degree of disorder. We study two cases: A constant intensity reflectance and the reflectance of thin films. Especially in the second case, we find that in the experimentally important regime for the film thicknesses, the transport-mean-free path l;{ *} does not significantly depend on the topological and geometrical disorder of the Voronoi foams including the periodic Kelvin foam. This may indicate that the detailed structure of foams is not crucial for understanding the diffusive transport of light. Furthermore, our theoretical values for l;{ *} fall in the same range as the experimental values observed in dry foams. One can therefore argue that liquid films contribute substantially to the diffusive transport of light in dry foams.
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Affiliation(s)
- Zeinab Sadjadi
- Institute for Advanced Studies in Basic Sciences (IASBS), P. O. Box 45195-1159, Zanjan 45195, Iran
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13
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Kienle A. Anisotropic light diffusion: an oxymoron? PHYSICAL REVIEW LETTERS 2007; 98:218104. [PMID: 17677814 DOI: 10.1103/physrevlett.98.218104] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2007] [Indexed: 05/16/2023]
Abstract
Light propagation in anisotropic random media is studied in the steady-state and time domains. Solutions of the anisotropic diffusion equation are compared to results obtained by the Monte Carlo method. Contrary to what has been reported so far, we find that even in the "diffusive regime" the anisotropic diffusion equation does not describe correctly the light propagation in anisotropic random media.
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Affiliation(s)
- Alwin Kienle
- Institut für Lasertechnologien in der Medizin und Messtechnik, Helmholtzstrasse 12, D-89081 Ulm, Germany.
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14
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Mertelj A, Copic M. Anisotropic diffusion of light in polymer dispersed liquid crystals. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 75:011705. [PMID: 17358171 DOI: 10.1103/physreve.75.011705] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Indexed: 05/14/2023]
Abstract
Anisotropic diffusion of light was experimentally first observed in bulk nematic liquid crystals. The origin of anisotropy in such a system is due to the optical anisotropy of nematic liquid crystal and to anisotropic scattering of light from nematic orientational fluctuations. In polymer dispersed liquid crystals (PDLCs) anisotropic scatterers-i.e., nematic droplets-are embedded in an optically isotropic polymer. The anisotropy of diffusion of light in this system therefore depends only on the anisotropic scattering from a single nematic droplet and on the average orientation of the droplets in PDLCs. In the absence of an external field droplets in PDLCs are randomly oriented and diffusion of light is isotropic. In an external field the droplets are on average oriented in the direction of the external field and the diffusion of light becomes anisotropic. We calculated the diffusion tensor and expected anisotropy of the diffusion of light as a function of an external field, kR , and volume fraction using the theory developed for bulk nematic liquid crystals. Our calculations show that the anisotropy of diffusion tensor can have both the signs and that the magnitude of diffusion constants increase with increasing external field.
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Affiliation(s)
- Alenka Mertelj
- J. Stefan Institute, Jamova 39, SI-1001 Ljubljana, Slovenia
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15
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van Tiggelen BA, Heiderich A, Maynard R. Light Diffusion in Oriented Nematic Liquid Crystals. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/10587259708042773] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Bart A. van Tiggelen
- a CNRS/Laboratoire de Physique et Modélisation des Systèmes Condensés , Université Joseph Fourier, Maison des Magistères , B.P. 166, 38042, Grenoble , Cedex , 9 , France
| | - Anne Heiderich
- a CNRS/Laboratoire de Physique et Modélisation des Systèmes Condensés , Université Joseph Fourier, Maison des Magistères , B.P. 166, 38042, Grenoble , Cedex , 9 , France
| | - Roger Maynard
- a CNRS/Laboratoire de Physique et Modélisation des Systèmes Condensés , Université Joseph Fourier, Maison des Magistères , B.P. 166, 38042, Grenoble , Cedex , 9 , France
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16
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Affiliation(s)
- Bart A. van Tiggelen
- a CNRS/Physique et Modélisation des Systèmes Condensés Maison des Magistères/UJF , B.P. 166 , 38042 , Grenoble Cedex 9 , France
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17
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Stark H. Radiative Transfer Theory and Diffusion of Light in Nematic Liquid Crystals. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/10587259808025106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Holger Stark
- a Institut für Theoretische und Angewandte Physik, Universität Stuttgart , Pfaffenwaldring 57, 70550 , Stuttgart , Germany
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18
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Miri M, Madadi E, Stark H. Diffusive transport of light in a Kelvin foam. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2005; 72:031111. [PMID: 16241415 DOI: 10.1103/physreve.72.031111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2005] [Indexed: 05/05/2023]
Abstract
Although diffusing-wave spectroscopy has already been successfully applied to study dynamic properties of foams, we still lack a clear understanding of the diffusive transport of photons in foams. In this paper, we present a thorough study of photon diffusion in the Kelvin structure as an example for a three-dimensional model foam. We consider the photons' random walk as they are reflected or transmitted by the liquid films according to the rules of ray optics. For constant reflectance and special one- and two-dimensional photon paths, we are able to calculate diffusion constants analytically. Extensive numerical simulations reveal a remarkable similarity with our previous two-dimensional investigations. To implement a more realistic model, we use thin-film reflectances. The simulated diffusion constants exhibit oscillations for varying film thickness d which vanish when disorder is introduced in d. Absolute values and the behavior at small d agree with measurements in very dry foams providing a strong argument for the importance of liquid films in the diffusive photon transport. An analytical theory with a minimum of input parameters reproduces the numerical results.
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Affiliation(s)
- MirFaez Miri
- Institute for Advanced Studies in Basic Sciences, Zanjan, 45195-1159, Iran
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19
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Wiersma DS, Sapienza R, Mujumdar S, Colocci M, Ghulinyan M, Pavesi L. Optics of nanostructured dielectrics. ACTA ACUST UNITED AC 2005. [DOI: 10.1088/1464-4258/7/2/025] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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20
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Gottardo S, Cavalieri S, Yaroshchuk O, Wiersma DS. Quasi-two-dimensional diffusive random laser action. PHYSICAL REVIEW LETTERS 2004; 93:263901. [PMID: 15697980 DOI: 10.1103/physrevlett.93.263901] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2004] [Indexed: 05/24/2023]
Abstract
We report on random lasing in a disordered system in which the multiple scattering feedback mechanism can be switched from a three-dimensional random walk to a quasi-two-dimensional type of transport. The emission from this system is anisotropic, extraordinary polarized, and is controlled via an external electric field. The phenomenon is observed in dye-doped polymer dispersed liquid crystals and makes use of the strong scattering anisotropies in these materials.
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Affiliation(s)
- Stefano Gottardo
- European Laboratory for Nonlinear Spectroscopy and INFM, 50019 Sesto Fiorentino (Florence), Italy.
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21
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Sapienza R, Mujumdar S, Cheung C, Yodh AG, Wiersma D. Anisotropic weak localization of light. PHYSICAL REVIEW LETTERS 2004; 92:033903. [PMID: 14753877 DOI: 10.1103/physrevlett.92.033903] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2003] [Indexed: 05/20/2023]
Abstract
We have observed angular anisotropy in weak localization of light from highly scattering, orientationally ordered, nematic liquid crystals. This demonstration of angular anisotropy in a multiple-scattering interference phenomenon was facilitated by a light scattering instrument with extraordinary angular resolution. The measured anisotropies were consistent with a simple model of coherent backscattering generalized for propagation-direction dependent mean free paths.
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Affiliation(s)
- Riccardo Sapienza
- European Laboratory for Nonlinear Spectroscopy and INFM, 50019 Sesto Fiorentino, Florence, Italy
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22
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Liu Z, Lin Z, Chui ST. Electromagnetic scattering by spherical negative-refractive-index particles: Low-frequency resonance and localization parameters. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2004; 69:016619. [PMID: 14995748 DOI: 10.1103/physreve.69.016619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2003] [Indexed: 05/24/2023]
Abstract
The Mie scattering of electromagnetic waves of wave vector k by spherical negative-refractive-index particles of radius a exhibits an unusual resonance at ka-->0. The scattering enhancement from the ka-->0 resonance is insensitive to the size of scatterers, distinct from the Mie scattering resonances from positive-refractive-index particles. For media consisting of a collection of the negative-refractive-index particles, the unusual resonance results in a significant reduction of the localization parameter, providing a possibility to reach the light localization transition by reducing the wave vector k, in analogy to electronic systems.
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Affiliation(s)
- Zheng Liu
- Surface Physics Laboratory and Research Center of Theoretical Physics, Fudan University, Shanghai 200433, China
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23
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Graca M, Wieczorek SA, Hołyst R. Growth of Polystyrene Domains in Isotropic, Nematic and Smectic Phase of 8CB Liquid Crystal. Macromolecules 2003. [DOI: 10.1021/ma034135b] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M. Graca
- Institute of Physical Chemistry PAS, Department III, Kasprzaka 44/52, 01-224 Warsaw, Poland, and WMP-SNS, Cardinal Stefan Wyszyṅski University, Dewajtis 5, Warsaw, Poland
| | - S. A. Wieczorek
- Institute of Physical Chemistry PAS, Department III, Kasprzaka 44/52, 01-224 Warsaw, Poland, and WMP-SNS, Cardinal Stefan Wyszyṅski University, Dewajtis 5, Warsaw, Poland
| | - R. Hołyst
- Institute of Physical Chemistry PAS, Department III, Kasprzaka 44/52, 01-224 Warsaw, Poland, and WMP-SNS, Cardinal Stefan Wyszyṅski University, Dewajtis 5, Warsaw, Poland
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24
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Graca M, Wieczorek SA, Hołyst R. Polymer domain growth in ordered liquid crystalline matrices. PHYSICAL REVIEW LETTERS 2003; 90:115504. [PMID: 12688941 DOI: 10.1103/physrevlett.90.115504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2002] [Indexed: 05/24/2023]
Abstract
The growth of polymer domains in the isotropic, nematic, and smectic matrices is studied by the light scattering. In the smectic and isotropic matrices the growth is diffusive, and in the nematic matrix it is influenced by the elastic forces. The scaling is obeyed. A crossover to the wetting fast-mode hydrodynamic regime is also observed at long times. In order to perform these measurements we had to eliminate the multiple scattering of light.
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Affiliation(s)
- M Graca
- Institute of Physical Chemistry, Polish Academy of Science, Department III, Kasprzaka 44/52, 01224 Warsaw, Poland
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25
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Pinheiro FA, van Tiggelen BA. Light transport in chiral and magnetochiral random media. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2003; 20:99-105. [PMID: 12542323 DOI: 10.1364/josaa.20.000099] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We present a microscopic approach to study electromagnetic wave propagation in media with broken mirror symmetry. We introduce and calculate the transport mean free path l*C associated with the residual polarization of diffuse light in chiral systems. In chiral media subject to an external magnetic field B, all symmetry requirements exist to create a macroscopic "super" light current in the direction of B that persists even in the absence of a spatial photon density gradient. However, we show that such a current is identically zero in our model. We finally show the existence of a linear magnetotransmission in magnetochiral media.
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Affiliation(s)
- Felipe A Pinheiro
- Laboratoire de Physique et Modélisation des Milieux Condensés, Centre National de la Recherche Scientifique/Université Joseph Fourier, B.P. 166, 38042 Grenoble Cedex 09, France.
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Johnson PM, Bret BPJ, Rivas JG, Kelly JJ, Lagendijk A. Anisotropic diffusion of light in a strongly scattering material. PHYSICAL REVIEW LETTERS 2002; 89:243901. [PMID: 12484943 DOI: 10.1103/physrevlett.89.243901] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2002] [Indexed: 05/24/2023]
Abstract
Light transport in a strongly scattering, strongly anisotropic material is studied experimentally using both static and time-resolved techniques. Both the static and the dynamic results are well characterized by a diffusion equation with an anisotropic diffusion tensor and a scalar absorption term. Light diffuses 4.0 times faster along the uniaxial axis of the material compared with diffusion in the orthogonal directions.
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Affiliation(s)
- Patrick M Johnson
- Van der Waals-Zeeman Instituut, Universiteit van Amsterdam, The Netherlands.
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27
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Skipetrov SE. Temporal fluctuations of waves in weakly nonlinear disordered media. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2001; 63:056614. [PMID: 11415038 DOI: 10.1103/physreve.63.056614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2000] [Indexed: 05/23/2023]
Abstract
We consider the multiple scattering of a scalar wave in a disordered medium with a weak nonlinearity of Kerr type. The perturbation theory, developed to calculate the temporal autocorrelation function of scattered wave, fails at short correlation times. A self-consistent calculation shows that for nonlinearities exceeding a certain threshold value, the multiple-scattering speckle pattern becomes unstable and exhibits spontaneous fluctuations even in the absence of scatterer motion. The instability is due to a distributed feedback in the system "coherent wave + nonlinear disordered medium." The feedback is provided by the multiple scattering. The development of instability is independent of the sign of nonlinearity.
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Affiliation(s)
- S E Skipetrov
- Laboratoire de Physique et Modélisation des Milieux Condensés, Université Joseph Fourier, Maison des Magistères-CNRS, Bôite Postale 166, 38042 Grenoble 9, France
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Hennino R, Trégourès N, Shapiro NM, Margerin L, Campillo M, van Tiggelen BA, Weaver RL. Observation of equipartition of seismic waves. PHYSICAL REVIEW LETTERS 2001; 86:3447-3450. [PMID: 11327992 DOI: 10.1103/physrevlett.86.3447] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2000] [Indexed: 05/23/2023]
Abstract
Equipartition is a first principle in wave transport, based on the tendency of multiple scattering to homogenize phase space. We report observations of this principle for seismic waves created by earthquakes in Mexico. We find qualitative agreement with an equipartition model that accounts for mode conversions at the Earth's surface.
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Affiliation(s)
- R Hennino
- Laboratoire de Géophysique Interne et Tectonophysique, Observatoire de Grenoble, Université Joseph Fourier, B.P. 53, 38041 Grenoble Cedex, France
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Pinheiro FA, Martinez AS, Sampaio LC. Vanishing of energy transport velocity and diffusion constant of electromagnetic waves in disordered magnetic media. PHYSICAL REVIEW LETTERS 2000; 85:5563-5566. [PMID: 11136047 DOI: 10.1103/physrevlett.85.5563] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2000] [Indexed: 05/23/2023]
Abstract
The energy transport velocity v(E) and the diffusion constant D of electromagnetic waves in the presence of randomly distributed ferromagnetic scatterers are studied. v(E) presents a strong dependence on the relative magnetic permeability mu and, unlike the nonmagnetic case, exhibits sharp drops in the small-particle limit and never coincides with the phase velocity v(p). Both v(E) and D exhibit an oscillatory dependence on mu and vanish for certain values of mu. Since mu of ferromagnetic scatterers strongly depends on the temperature and applied magnetic field, we suggest that these facts can be explored in technological applications.
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Affiliation(s)
- F A Pinheiro
- Centro Brasileiro de Pesquisas Física/CNPq, Rua Dr. Xavier Sigaud, 150, Urca, CEP 22290-180, Rio de Janeiro, RJ, Brazil.
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Wiersma DS, Muzzi A, Colocci M, Righini R. Time-resolved experiments on light diffusion in anisotropic random media. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 2000; 62:6681-6687. [PMID: 11102019 DOI: 10.1103/physreve.62.6681] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2000] [Indexed: 05/23/2023]
Abstract
Multiple light scattering in isotropic and anisotropic media is studied experimentally with an optical gating technique, as commonly used in fluorescence spectroscopy. The experimental setup permits an accurate analysis of the propagation of a short light pulse through disordered or partially ordered media. The diffusion constant of some isotropic systems is reported, and the anisotropy in the diffusion constant for light diffusion through liquid crystals is observed. For the time-resolved data, good agreement with diffusion theory is found in all cases, including the liquid crystal in the nematic phase.
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Affiliation(s)
- DS Wiersma
- European Laboratory for Non-Linear Spectroscopy and Instituto Nazionale per la Fisica della Materia, Largo Enrico Fermi 2 (Arcetri), 50125 Florence, Italy
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Ponomarenko SA, Shchegrov AV. Spectral changes of light produced by scattering from disordered anisotropic media. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1999; 60:3310-3. [PMID: 11970145 DOI: 10.1103/physreve.60.3310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/1999] [Indexed: 04/18/2023]
Abstract
We investigate theoretically changes in the spectrum of polychromatic light scattered by a disordered, birefringent medium. We derive an expression for the spectrum of scattered light for ordinary and extraordinary incident waves within the accuracy of the first Born approximation. Using this result, we analyze the changes in the spectrum of light due to the combined action of disorder and anisotropy in the scattering process.
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Affiliation(s)
- S A Ponomarenko
- Department of Physics and Astronomy and Rochester Theory Center for Optical Science and Engineering, University of Rochester, Rochester, New York 14627, USA
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Shen Y, Chen SH, Hsu CH, Lai Y. Interference patterns of scattering light induced by orientational fluctuations in an electric-field-biased nematic liquid-crystal film. OPTICS LETTERS 1998; 23:891-893. [PMID: 18087374 DOI: 10.1364/ol.23.000891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A new light-scattering phenomenon from a planar aligned nematic liquid-crystal film is observed and studied. This new phenomenon exhibits ring patterns in the orthogonal polarization. A simple model based on optical interference has been developed, and its predictions agree well with experimental observation.
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Kao MH, Jester KA, Yodh AG, Collings PJ. Observation of Light Diffusion and Correlation Transport in Nematic Liquid Crystals. PHYSICAL REVIEW LETTERS 1996; 77:2233-2236. [PMID: 10061892 DOI: 10.1103/physrevlett.77.2233] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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