Scattering Light by а Cylindrical Capsule with Arbitrary End Caps in the Rayleigh-Gans-Debye Approximation

• Main Author: K. A. Shapovalov
• Format: Article
• Language: Russian
• Published: MGTU im. N.È. Baumana 2015-01-01
• Series: Nauka i Obrazovanie
• Subjects: light scattering; phase function; optically “soft” particles
• Online Access: http://technomag.edu.ru/jour/article/view/300

<p>The paper concerns the light scattering problem of biological objects of complicated structure.</p><p>It considers optically “soft” (having a refractive index close to that of a surrounding medium) homogeneous cylindrical capsules, composed of three parts: central one that is cylindrical and two symmetrical rounding end caps. Such capsules can model more broad class of biological objects than the ordinary shapes of a spheroid or sphere. But, unfortunately, if a particle has other than a regular geometrical shape, then it is very difficult or impossible to solve the scattering problem analytically in its most general form that oblige us to use numerical and approximate analytical methods. The one of such approximate analytical method is the Rayleigh-Gans-Debye approximation (or the first Born approximation).</p><p>So, the Rayleigh-Gans-Debye approximation is valid for different objects having size from nanometer to millimeter and depending on wave length and refractive index of an object under small phase shift of central ray.</p><p>The formulas for light scattering amplitude of cylindrical capsule with arbitrary end caps in the Rayleigh-Gans-Debye approximation in scalar form are obtained. Then the light scattering phase function [or element of scattering matrix f11] for natural incident light (unpolarized or arbitrary polarized light) is calculated.</p><p>Numerical results for light scattering phase functions of cylindrical capsule with conical, spheroidal, paraboloidal ends in the Rayleigh-Gans-Debye approximation are compared. Also numerical results for light scattering phase function of cylindrical capsule with conical ends in the Rayleigh-Gans-Debye approximation and in the method of Purcell-Pennypacker (or Discrete Dipole method) are compared. The good agreement within an application range of the RayleighGans-Debye approximation is obtained.</p><p>Further continuation of the work, perhaps, is a consideration of multilayer cylindrical capsule in the Rayleigh-Gans-Debye approximation.</p><p>The results of given paper may be used for the analysis not only light scattering, but also for the calculation of neutron diffraction and small-angle scattering of X-rays.</p>