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Analogy with Young apertures or Perot–Fabry cavities is used to propose a physical interpretation of light scattering by a bisphere. Dielectric or perfectly conductive particles are considered. The study is carried out in the far field, in the Fraunhofer approximation, in the electrodynamic regime (size parameter of spheres around 2) by means of the T-matrix algorithm. Single and multiple scattering phenomena are analysed in terms of interference, diffraction or scattering. It is shown in particular that the transition between single and multiple scattering mainly changes the ratio of the light that is scattered. In the multiple scattering regime, the shadow effect for perfectly conductive spheres and the cavity effect for dielectric spheres are discussed.

We discuss the problem of the calculation of light scattering properties from composite grains with large aspect ratio.

The paper is devoted to a theoretical investigation of the cross-polarization ratio of scattered light for randomly oriented particles of various shapes. The cases of spheroids, cylinders and fractal particles are considered in detail. The particles are assumed to be much larger than the wavelength of the incident light. Calculations are performed using the Monte Carlo ray-tracing code. Absorption of light by the particles is neglected. It was found that highly irregular fractal particles give the maximum ratio of the cross-polarization. Particles with a larger degree of symmetry (e.g. circular cylinders and spheroids) give smaller values. The highest values of the cross-polarization ratio lay in the backward hemisphere. They were smaller than 0.8 for all the cases considered.

A theory is developed to describe light scattering by clouds of statistically irregular particles using the Rayleigh-Gans-Debye approximation. The theory reproduces the expected behaviour due to irregularity, that is insensitivity to shape in forward scattering, smoothing of the polar diagram and an increase in backscattering. It also suggests that the particles can be represented by spheres with a size distribution equal to the probability distribution of the radius, provided that the scale height of the irregularity is not too large.

The authors present a method for the calculation of the scattering of light by a periodic two-dimensional array of spherical particles adsorbed on a uniform dielectric slab. Multiple scattering of light between the particles of the overlayer and between the overlayer and the substrate is taken fully into account. The method is applied to light scattering from a square lattice of gold particles on a sapphire substrate for which experimental data are available. The agreement between theory and experiment is reasonably good.

To effectively estimate the influence of multiple scattering caused by haze particles on the misestimating of CO2 concentrations, it is necessary to understand the scattering properties of haze particles in the shortwave infrared (SWIR) wavelength range (~1.6um) using satellite data. Due to the complexity of structures and components of haze particles, this paper investigates effects of particle size and chemical component on the scattering properties of both single non-spherical particles and aggregates for the 1.6um by using numerically effective medium theory and core-mantle theory. For the single non-spherical particles, the scattering parameters (e.g. scattering phase function, single scattering albedo, extinction coefficient and scattering coefficient) are calculated by combining the T-matrix method and the Maxwell-Garnett effective medium theory. For the aggregates, the particle-cluster aggregation algorithm is used to generate aggregates with different monomer numbers. And then, the Core-Mantle Generalized Multi-particle Mie (CMGMM) method is used to compute the scattering parameters. The results indicate that the scattering characteristics are significantly different for both single non-spherical particles and aggregates.

Improved formulae for the Mie scattering of three-layered spheres are presented. By means of comparisons between the scattering cross-sections of three-layered spheres and two-layered spheres, the influence of Mie resonances on the curves of the scattering cross-sections when varying the radius of the core layer is investigated. The transport properties of random media composed of two-layered spheres are investigated as well.

The application of the Sh-matrices technique developed within the T-matrix formalism allows for the derivation of analytic solutions to the light scattering from non-spherical particles. In this paper we derive such solutions for isolated prolate and oblate spheroids. Examples of calculations of spheroid scattering properties including the case of particles with high eccentricity are presented. Our results are compared with corresponding calculations using the discrete dipole approximation (DDA) method and analytical methods based on the separation of variables for the vector wave equations in the spheroidal coordinate system.

It is known that the efficiency of scattering of light by a particle is related to its size, geometry and optical constants of the material, since the theory of scattering by small particles developed by Mie in the beginning of the 20th century. However, the Mie scattering theory is valid just for a few special cases like a homogeneous sphere embedded on a medium of homogenous refraction index. More recently, some theoretical simulations on planar nano- particles have shown that the optical resonances are dependent on the shape of the particle. Simultaneously, local field enhancements take place on the particles when excited by an incident wave. A comprehensive knowledge of the optical behaviour of planar particles is of great importance for the development of optical devices at the nanoscale, as well as for the fast developing field of photonic crystals and the emerging field of diffractive optics. In this paper, we present optical investigations on arrays of triangular nanoparticles with sizes comparable with the wavelength. Particles were produced using the method developed by Fischer and the optical measurements have been made using a scanning confocal microscope and a total-internal- reflection system. The scattering of light by particles of some materials when excited by an evanescent field show a strong dependence on their relative orientation in the direction of incidence. The measured scattering patterns change with the polarization of light.

A multiple scattering method is described for calculating extinction, absorption and scattering cross-sections for dielectric particles of arbitrary shape, whose dimensions are comparable to the wavelength of the incident radiation. Numerical application to spheres agrees well with the Mie theory. An extension for a collection of arbitrarily shaped particles with application to zodiacal light is also given.

When light is scattered by a cloud of particles of a wide range of sizes, the intensity scattered in any direction is built up from the contributions of particles of all dimensions. For forwards scattering the relative values of these contributions have been calculated as a function of diameter, by two different approximate formulae for the angular distribution of the light scattered by spheres. The approximations used are: (1) that of Rayleigh and Gans, and (2) Kirchhoff diffraction by opaque circular disks. For the latter, the scattering by a cloud of disks whose diameters are log-normally distributed with a standard geometric deviation of 2.03 has also been computed. It is concluded that the predominance of the light scattered by larger particles limits the usefulness of light scattering as a means of obtaining a mean particle size to suspensions containing a comparatively narrow range of particle sizes.

An examination is made of the intensity of light scattered nearly backwards by spherical dielectric particles illuminated by natural light. It is shown that, for particles larger than the wavelength, the intensity varies with direction in a characteristic way, agreeing well with an approximate theory at small angles.

The spectrum of light scattered by particles suspended in a turbulent fluid is investigated theoretically.

The diffraction approximation and exact Mie theory, for treating light scattering by particles, are briefly compared for different sizes. Attention is drawn to the simplification of the screening function which occurs if the particles are opaque. Methods of measuring small particles in the presence of large ones are discussed and reference is made to new techniques for measuring particle concentration.