scispace - formally typeset
Search or ask a question

Showing papers on "Light scattering published in 1985"


BookDOI
01 Jan 1985

4,777 citations


Journal ArticleDOI
TL;DR: Retrodiffusion de la lumiere augmentee dependant ofert de la polarisation dans une suspension concentree de particules de polystyrene dans l'eau.
Abstract: We report the observation of weak localization of light in a random medium. In a sample consisting of a highly concentrated suspension of polystyrene particles in water, polarization-dependent enhanced backscattering of laser light was found within a cone of approximately 0.2\ifmmode^\circ\else\textdegree\fi{} (half angle) for the highest concentration.

887 citations


Journal ArticleDOI
TL;DR: In this article, it was shown that "impulsive" stimulated Raman scattering (ISRS) should occur, with no laser intensity threshold, when a sufficiently short laser pulse passes through many types of matter.
Abstract: It is shown that ‘‘impulsive’’ stimulated Raman scattering (ISRS) should occur, with no laser intensity threshold, when a sufficiently short laser pulse passes through many types of matter. ISRS excitation of coherent optic phonons, molecular vibrations, and other excitations (including rotational, electronic, and spin) may play important roles in femtosecond pulse interactions with molecules, crystals, glasses (including optical fibers), semiconductors, and metals. Spectroscopic applications of ISRS, including time‐resolved spectroscopy of vibrationally distorted molecules and crystals, are discussed.

498 citations


Journal ArticleDOI
TL;DR: La diffusion directe de la lumiere par les modes acoustiques guides thermiquement excites d'une fibre optique constitue une source de bruit thermique.
Abstract: Forward light scattering by the thermally excited guided acoustic modes of an optical fiber produce numerous narrow lines not predicted by the usual theory of Brillouin scattering. Optical heterodyne detection has been used to resolve the scattering spectrum which begins at about 20 MHz and extends to the detection limit. A simple theory quantitatively accounts for the frequencies, polarizations, and intensities of the components. The light scattering from these modes constitutes a thermal-noise source in optical fibers that may prove significant in other experiments.

474 citations


Journal ArticleDOI
TL;DR: In this paper, the complete characterization of scattered light is described in the context of Stokes vectors and Mueller matrices which highly motivates the measuring procedures, and the most general form of the scattering matrix coupled with polarizers and quarter wave plates elegantly demonstrates the physical relationship among the matrix elements and polarization measurements.
Abstract: The complete characterization of scattered light is described in the context of Stokes vectors and Mueller matrices which highly motivates the measuring procedures. The most general form of the scattering matrix coupled with polarizers and quarter wave plates elegantly demonstrates the physical relationship among the matrix elements and polarization measurements.

383 citations


Journal ArticleDOI
TL;DR: In this article, the authors apply radiative transfer theory to seismic wave propagation and formulate in the frequency domain the energy density distribution in space for a point source, considering the cases of isotropic scattering and strong forward scattering.
Abstract: Summary. In order to separate the scattering effect from the intrinsic attenuation, we need a multiple scattering model for seismic wave propagation in random heterogeneous media. In this paper, we apply radiative transfer theory to seismic wave propagation and formulate in the frequency domain the energy density distribution in space for a point source. We consider the cases of isotropic scattering and strong forward scattering. Some numerical examples are shown. It is seen that the energy density-distance curves have quite different shapes depending on the values of medium seismic albedo Bo = qs/(qs t q,), where vs is the scattering coefficient and va is the absorption coefficient of the medium. For a high albedo (B> 0.5) medium, the energy-distance curve is of arch shape and the position of the peak is a function of the extinction coefficient of the medium ve = qs + qa. Therefore it is possible to separate the scattering effect and the absorption based on the measured energy density distribution curves.

346 citations


Book
31 Oct 1985
TL;DR: In this article, Collision-Induced Dipole moments are calculated for the effect of collision-induced dipole moments in a multipole model on the Spectral Spectral Spectrum of Compressed Gases.
Abstract: Section 1: Compressed Gases and the Effect of Density.- A. Far Infrared and Infrared Absorption.- Classical Multipole Models: Comparison with Ab Initio and Experimental Results.- Ab Initio Calculations of Collision Induced Dipole Moments.- A Comparative Study of the Dielectric, Refractive and Kerr Virial Coefficients.- The Infrared and Raman Line Shapes of Pairs of Interacting Molecules.- Collision-Induced Absorption in the Microwave Region.- Collision-Induced Absorption in N2 at Various Temperatures.- Far Infrared Absorption Spectra in Gaseous Methane from 138 to 296 K.- Induced Vibrational Absorption in the Hydrogens.- Simultaneous Transitions in Compressed Gas Mixtures.- Molecular Motions in Dense Fluids from Induced Rotational Spectra.- Intercollisional Interference - Theory and Experiment.- Workshop Report: Infrared Absorption in Compressed Gases.- B. Light Scattering.- Ab Initio and Approximate Calcuations of Collision-Induced Polarizabilities.- Depolarization Ratio of Light Scattered by a Gas of Isotropic Molecules.- Depolarized Interaction Induced Light Scattering Experiments in Argon, Krypton, Xenon.- Interaction Induced Rotational Light Scattering in Molecular Gases.- Workshop Report: Light Scattering in Compressed Gases.- Section 2: Liquids and Liquid State Interactions.- A. Atomic Systems.- Theory of Collision-Induced Light Scattering and Absorption in Dense Rare Gas Fluids.- Calculation of Spectral Moments for Induced Absorption in Liquids.- B. Molecular Systems.- Interaction-Induced Vibrational Spectra in Liquids.- Far Infrared Induced Absorption in Highly Compressed Atomic and Molecular Systems.- Theoretical Interpretation of the Far Infrared Absorption Spectrum in Molecular Liquids: Nitrogen.- Molecular Dynamics Studies of Interaction Induced Absorption and Light Scattering in Diatomic Systems.- Interaction Induced Light Scattering from Tetrahedral Molecules.- Local Fields in Liquids.- Pressure - An Essential Experimental Variable in Spectroscopic Studies of Liquids.- Workshop Report: Liquids and Liquid State Interactions.- Section 3: Solid State, Amorphous, and Ionic Systems.- Study of the Collective Excitations in H2 as Observed in Far Infrared Absorption.- Induced Light Scattering in Disordered Solids.- Infrared Induced Absorption of Nitrogen and Methane Adsorbed in NaA Synthetic Zeolite.- Charge Induced Effects in Solid Tritium and Deuterium.- Workshop Reports: Some Considerations on Spectra Induced by Intermolecular Interactions in Molecular Solids and Amorphous Systems.- Section 4: Induced Transitions in Allowed Spectra.- Collision-Induced Effects in Allowed Infrared and Raman Spectra of Molecular Fluids.- Raman Scattering from Linear Molecules.- The Interference of Molecular and Interaction-Induced Effects in Liquids.- Interaction Induced Spectra of "Large" Molecules in Liquids.- The Infrared Spectrum of HD.- Workshop Report: The Interference of Induced and Allowed Molecular Moments in Liquids.- Section 5: Related Subjects.- Contribution of Bound Dimers, (N2)2, to the Interaction Induced Infrared Spectrum of Nitrogen.- Vibrational Spectral Lineshapes of Charge Transfer Complexes.- Collision-Induced Effects in Planetary Atmospheres.- Time-Domain Separation of Collision Induced and Allowed Raman Spectra.- Collision-Induced Radiative Transitions at Optical Frequencies.- Comments on Hyper-Rayleigh Scattering.- Comments on the Spectra of the Halogens and Halogen Complexes in Solution.- Author index.- Chemical index.

343 citations


Journal ArticleDOI
TL;DR: Stimulated Raman scattering from an individual liquid droplet has been observed and the occurrence of a series of spectrally narrow peaks that are regularly spaced in wavelength is consistent with morphology-dependent resonances of the droplet, which acts as an optical resonator.
Abstract: Stimulated Raman scattering (SRS) from an individual liquid droplet (~30-microm radius) has been observed for H(2)O, D(2)O, and ethanol. The occurrence of a series of spectrally narrow peaks that are regularly spaced in wavelength is consistent with morphology-dependent resonances of the droplet, which acts as an optical resonator. The input intensity required to achieve the SRS threshold for the droplet is considerably less than that for the liquid in an optical cell.

317 citations


Journal ArticleDOI
TL;DR: From computations the smallest particles that can be photographed in various fluid measurement situations, including air and water, have been determined in terms of system parameters such as laser power, light sheet geometry, f/No.
Abstract: Mie scattering computations have been performed for light scattered by small particles from a pulsed sheet of laser illumination and collected and imaged by a camera lens. From these computations the smallest particles that can be photographed in various fluid measurement situations, including air and water, have been determined in terms of system parameters such as laser power, light sheet geometry, f/No., and photographic film properties. The particle scattering requirements of the individual particle image mode and the speckle mode are compared.

300 citations


Journal ArticleDOI
TL;DR: The remarkable optical properties of metallic silver give rise not only to the brilliant colors exhibited by colloidal silver but also to a variety of other phenomena such as absorption and scattering effects, luminescence, photophoresis, and surface-enhanced Raman scattering as discussed by the authors.

295 citations


Journal ArticleDOI
TL;DR: In this article, a transient three-pulse scattering technique for measuring ultrafast dephasing times in condensed matter is analyzed using a perturbative solution of the density matrix equation.
Abstract: A novel transient three-pulse scattering technique for measuring ultrafast dephasing times in condensed matter is analyzed using a perturbative solution of the density matrix equation. The advantages of this technique include subpulsewidth resolution, a clear distinction between homogeneous and inhomogeneous broadening, and sensitivity to spectral cross-relaxation. Its application to the case of a multilevel resonance is also considered. We report results of femtosecond dephasing experiments with dye molecules in liquids and in a polymer host. The dephasing time is determined to be less than 20 fsec for dyes in solution at room temperature. At low temperatures in polymers, a transition from homogeneous to inhomogeneous broadening has been observed and studied as a function of temperature.

Journal ArticleDOI
TL;DR: A light scattering technique for simultaneously determining the volume (V) and hemoglobin concentration (HC) of individual sphered red blood cells (RBCs) is described and results are compared with those obtained from hematological reference measurements.
Abstract: A light scattering technique for simultaneously determining the volume (V) and hemoglobin concentration (HC) of individual sphered red blood cells (RBCs) is described. Light scattered into two angular intervals yields measurements S1 and S2, respectively. Since a sphered RBC is essentially a homogeneous dielectric sphere having a complex refractive index that is linear in HC, with a proper choice of detector acceptance angles, tables relating V and HC to S1 and S2 can be computed via Mie theory. Absolute calibration is possible using droplets of water-immisible oils of accurately known refractive index. Results of experimental tests of the method are compared with those obtained from hematological reference measurements.

Journal ArticleDOI
TL;DR: It is shown that the dependence of absorbance on mitochondrial concentration can be linearized, resulting in an intrinsic light scattering parameter which is independent of the concentration and source of mitochondria, and the absorbance osmotic curve is segmentally linear.

Journal ArticleDOI
TL;DR: In this paper, the authors calculate the total electromagnetic field from a surface of finitely sized metal or dielectric particles by superposition: Scalar potentials characterizing a single particle are convoluted with a distribution function describing the particle positions.
Abstract: Amplified electromagnetic fields generated by a surface of finitely sized metal or dielectric particles are calculated. Regular arrays of particles produced by lithographic techniques and stochastic particle distributions that occur, e.g., in island films, are discussed. Retarded dipolar interactions between the particles are explicitly taken into account. Particles of finite size are considered for which dynamic depolarization and radiation damping effects are important. Limits of validity of the present approach are indicated. The total electromagnetic field from the surface is calculated by superposition: Scalar potentials characterizing a single particle are convoluted with a distribution function describing the particle positions. The surface Hertz vector is obtained from the single-particle Hertz vector by convolution with a two-dimensional Shah function representing the array or with the autocorrelation function of the stochastic surface. A plane-wave description of the dipolar fields is used, whereby the convolution is transformed into a simple multiplication in Fourier space. Cylindrical, general spheroidal, and spherical shapes are considered for the individual particle. Particle dipole moments are obtained by a self-consistent procedure. Dipolar interactions result in shifts and broadening of the particle plasmon resonances, which are responsible for the local intensity enhancement. A set of universal curves is given from which shift and broadening can be calculated for particles of all sizes and shapes. Extrema in the dipolar interactions arise when grating orders change from radiative to evanescent character. The strong variation of the Raman enhancement with angle and wavelength in the vicinity of these extrema is clearly predicted from the Hertz-vector calculation. The formalism described permits one to calculate electromagnetic properties of the surface and enhancement factors for any electromagnetic process occurring at or near the surface. As examples, the calculation of reflectivities for s-and p-polarized excitation and surface-enhanced Raman-scattering cross sections are discussed.

Journal ArticleDOI
TL;DR: In this article, the mean square amplitudes of the scattered field for P-P, P-S, S-P and S-S scattering by an elastic random medium characterized by perturbations of elastic constants and density were derived.
Abstract: In this paper we use Born approximations to derive the mean square amplitudes of the scattered field for P-P, P-S, S-P, and S-S scattering by an elastic random medium characterized by perturbations of elastic constants and density. We also obtain the total scattered power or the scattering coefficient for the case of an incident P wave. We find that, in both the spatial scattering pattern and the frequency dependence of the scattering coefficient, there are some significant differences between scalar wave scattering and elastic wave scattering. These differences are most striking when the wavelength is comparable to the size of inhomogeneities, which is often encountered in the study of short-period seismic body waves. Under certain conditions, the perturbations of the medium parameters can be decomposed into an impedance term and a velocity term. In the forward direction, scattered waves are primarily controlled by the velocity perturbations. For backscattering, scattered waves are generated mainly by impedance perturbations. We derive low- and high-frequency asymptotic forms of the directional and total scattering coefficients. In the low-frequency range, Rayleigh scattering with fourth-power frequency dependence occurs. For the high-frequency range the scattered power for common-mode scattering has a second-power frequency dependence, which is attributed to velocity perturbations. The scattered power of converted waves reaches a maximum, for the case of an exponential correlation function, in the high-frequency range. We find that the scalar wave theory can be only approximately used for the forward scattering problem in the high-frequency range, such as the phase and amplitude fluctuations in large seismic arrays. The case of coda wave excitation by local earthquakes, which is a backscattering or a large-angle-scattering problem, must be handled by the full elastic wave theory. A preliminary analysis of past observations using our theory suggests that the lithosphere may have multiple-scale inhomogeneities. Besides the 10–20 km scale velocity inhomogeneities revealed by the forward scattering observations at LASA and NORSAR, the lithosphere in tectonically active regions may be rich in small-scale (less than 1 km) inhomogeneities.

Journal ArticleDOI
TL;DR: In this paper, the authors consider the role of cavity sites in surface-enhanced optical processes in terms of the incident beam direction, polarization and frequency, geometry and optical properties of the substrate and its environment and of the optical properties, location and orientation (relative to the substrate) of the adsorbed molecule.

Journal ArticleDOI
01 Jul 1985-Langmuir
TL;DR: In this paper, a l'etude de suspensions de particules mono- or polydispersees, subissant le mouvement brownien, is described.
Abstract: Donnees relatives a l'etude de suspensions de particules mono- ou poly-dispersees, subissant le mouvement brownien

Journal ArticleDOI
TL;DR: In this paper, a Bernoulli solution for determining the relative distribution of aerosol backscattering in the UV region is presented, and scattering ratio boundary values for these solutions are discussed.
Abstract: The differential absorption lidar (DIAL) technique generally assumes that atmospheric optical scattering is the same at the two laser wavelengths used in the DIAL measurement of a gas concentration profile. Errors can arise in this approach when the wavelengths are significantly separated, and there is a range dependence in the aerosol scattering distribution. This paper discusses the errors introduced by large DIAL wavelength separations and spatial inhomogeneity of aerosols in the atmosphere. A Bernoulli solution for determining the relative distribution of aerosol backscattering in the UV region is presented, and scattering ratio boundary values for these solutions are discussed. The results of this approach are used to derive a backscatter correction to the standard DIAL analysis method. It is shown that for the worst cases of severe range dependence in aerosol backscattering, the residual errors in the corrected DIAL O3 measurements were <10 ppbv for DIAL wavelengths at 286 and 300 nm.

Journal ArticleDOI
TL;DR: In this article, the effect of the scattering wave vector on both the intensity of scattered light and collective translational diffusion coefficient was investigated up to high concentrations, in the semidilute range, by means of elastic and quasielastic light scattering.

Journal ArticleDOI
TL;DR: Systeme polystyrene-cyclohexane dans un grand domaine de masse moleculaire et de concentration as discussed by the authors is a system that combines poly styrene and cyclohexanes.
Abstract: Systeme polystyrene-cyclohexane dans un grand domaine de masse moleculaire et de concentration

Journal ArticleDOI
TL;DR: In this article, a theory of the resonant nonspecular scattering of light from a randomly rough metal surface is fitted to experimental data in a way that permits the extraction of the two-dimensional Fourier transform g(k∥) of the correlation function of the surface profile function from the experimental results.
Abstract: Two problems involving the interaction of a volume electromagnetic wave with a randomly rough metal surface are studied. In the first part a recently constructed theory of the resonant nonspecular scattering of light from a randomly rough metal surface is fitted to experimental data in a way that permits the extraction of the two-dimensional Fourier transform g(k∥) of the two-point correlation function of the surface profile function from the experimental results. It is found that the resulting correlation function can have its first maximum away from k∥ = 0 and decays to zero with increasing k∥ in a nonmonotonic fashion. This form for g(k∥) has been obtained in recent, independent, experimental determinations of this function. In the second part the scattering of p-polarized light from a randomly rough grating is studied in a case in which the plane of incidence is normal to the grooves of the grating. A diagrammatic method that self-consistently takes into account the diagrams responsible for localization phenomena in other contexts is used in this analysis. It is shown that the contribution from these diagrams gives rise to an enhanced scattered intensity in the antispecular direction. As a by-product of this calculation, the localization of surface polaritons by surface roughness is demonstrated and their localization length is determined.

Journal ArticleDOI
TL;DR: The light scattering technique is shown to be capable of providing quantitative answers to important questions about solute transport across the inner membrane and erythritol permeability is found to be constant over the entire volume range.

Patent
11 Sep 1985
TL;DR: In this article, the concentration of multiple polyatomic gases are determined almost simultaneously by Raman scattering, where the gas sample is placed in a sampling cell located in the resonance cavity of a laser and a polarized laser beam having sufficient intensity to produce detectable signals of Raman scattered light is passed through the cell by means of a reflection mirror located parallel to the axis of the laser beam adjacent to and outside the cell.
Abstract: The concentration of multiple polyatomic gases are determined almost simultaneously by Raman scattering The gas sample is placed in a sampling cell located in the resonance cavity of a laser and a polarized laser beam having sufficient intensity to produce detectable signals of Raman scattered light is passed through the cell The scattered light is captured and redirected by means of a reflection mirror located parallel to the axis of the laser beam adjacent to and outside of the cell Signals of both inelastic Raman scattered light and elastic laser scattered light are collected by a collection lens means opposite the reflection mirror and outside the gas cell The collection lens is also parallel to the axis of the laser beam The collected scattered signals are directed onto a laser line rejection filter where the scattered elastic laser signals are filtered out and the inelastic Raman scattered signals are transmitted to come in contact with a rotating filter wheel containing a series of interference filters with each filter being specific to the transmission of one Raman line The Raman lines passing through the rotating filters are sensed sequentially by a single detector means and amplified and converted into digital electrical pulses which are processed and converted into visual readouts indicative of the concentration of each of the polyatomic molecules in the gas being determined

Journal ArticleDOI
TL;DR: A rod-to-coil conformational transition has been demonstrated for polydiacetylene, 4-butoxy-carbonyl-methylurethane (4BCMU) in solution as mentioned in this paper.
Abstract: A rod‐to‐coil conformational transition has been demonstrated for polydiacetylene, 4‐butoxy‐carbonyl‐methylurethane (4BCMU) in solution. The transition can be induced by changing either the temperature or the quality of the solvent. The light scattering and spectroscopic data as a function of polymer concentration have shown that the transition is a single chain (intramolecular) phenomenon. However, because of the large end‐to‐end length (L≂1.2 μm) of the fully extended polymer, the dilute limit is not reached until concentrations below 10−5 g/cm3. At higher concentrations evidence of cluster growth and aggregation are observed prior to gelation which occurs above a critical concentration c0≂5×10−4 g/cm3. This cluster growth occurs as a result of the rod‐like conformation of the individual molecules, but it is not the cause of the transition. The large increase in scattering intensity (at fixed polymer concentration) on going from coil to rod follows directly from the change in dielectric constant due to ...

Journal ArticleDOI
TL;DR: In this paper, the authors report the introduction of a new dynamic light scattering technique, diffusion wave spectroscopy, which holds great promise for determining particle size measurements in concentrated or optically opaque systems.
Abstract: Methodologies based on light scattering measurements continue to dominate particle size instrumentation. With this review, we report the introduction of a new dynamic light scattering technique ― diffusion wave spectroscopy ― which holds great promise for determining particle size measurements in concentrated or optically opaque systems (see Photon Correlation Spectroscopy). The use of acoustic spectroscopy also appears to be a promising approach, although relatively few reports have appeared thus far (see Other Techniques)

Journal ArticleDOI
TL;DR: Overall, it was considered that the IRS systems and ellipsometric approaches offered the most promise for the design of a specific immunosensor device.

Journal ArticleDOI
TL;DR: Electron micrographs demonstrated that native vWF molecules are flexible, linear polymers, and the data presented provide the first evidence for a well-defined, repeating protomeric subunit, suggesting that the overall shape of polymers does not change with increasing size.

Journal ArticleDOI
TL;DR: In this article, a capacitively coupled, rf glow discharge of silane in argon was studied to determine the spatial dependence of particle light scattering, which is compatible with concepts of particle growth in sharp spatial zones near the plasma sheaths.
Abstract: A capacitively coupled, rf glow discharge of silane in argon was studied to determine the spatial dependence of particle light scattering. Light scattering from a pulsed laser at 500 nm shows sharp spatial peaks of scattered intensity near the electrodes. These scattering peaks are correlated with the plasma sheath edges because they exhibit spatial changes with discharge pressure characterized by a constant product of pressure and distance from the electrode. Light scattering at various silane mole fractions and gas flow rates is compatible with concepts of particle growth in sharp spatial zones near the plasma sheaths.

Journal ArticleDOI
TL;DR: In this article, the experimental and theoretical light flux-vs-time curves are compared by means of the Mie theory to determine particle size and number concentration in colloidal systems.

Journal ArticleDOI
TL;DR: On montre que des modes acoustiques guides excites thermiquement provoquent une modulation de phase and une depolarisation de the lumiere guidee par une fibre optique monomode.
Abstract: Forward light scattering by the thermally excited acoustic eigenmodes of an optical fiber produce numerous narrow lines not predicted by the bulk-interaction theory of Brillouin scattering. Optical heterodyne detection has been used to resolve the scattering spectrum which begins at about 20 MHz and extends to the detection limit.