Mie-scattering formalism for spherical particles embedded in an absorbing medium

Abstract

Most of the Mie-scattering calculations have been done for a particle embedded in a nonabsorbing host medium. Generalization to an absorbing host medium can be achieved (a) by modifying the calculation of the spherical Bessel functions to account for a complex argument and (b) by accounting properly for the net rate of incident, scattered, and absorbed energy. We present an extended formalism of Mie scattering for the case of an absorbing host medium. Numerical calculations show that for a large spherical particle embedded in an absorbing host medium the extinction efficiency approaches 1 compared with 2 for a nonabsorbing host medium. We conjecture that this difference is due to the suppression of diffraction when the radius of the sphere is large.

Parametric Analysis of Energy Absorption in Micro-particle Photophoresis in Absorbing Gaseous Media

“…The present calculation of HSF distribution within a particle in absorbing media has been successfully verified as comparing with the previous results 14 .…”

“…For an absorbing medium, the incident electric field amplitude, 0 exp( ), a E = -a k used in a number of previous studies 13,14,23 is adopted. The present calculation of HSF distribution within a particle in absorbing media has been successfully verified as comparing with the previous results 14 .…”

“…As to the absorption coefficient of air, k a , values up to 0.5 were used in previous studies 12,14 . Here, the values of k a from 0 to 0.2 are considered.…”

“…For an absorbing medium, the Mie theory is no longer valid and the Mie equations have to be modified. A few studies have been carried out to develop the theoretical models and the properties of light scattering by spherical [13][14][15][16][17] and non-spherical [18][19][20][21] particles suspended in the absorbing medium. From the above review of previous studies of microparticle photophoresis, it is found that the effects of optical properties of particle and gaseous medium on the radiants absorption were not investigated in details, especially in the case of absorbing medium.…”

Modeling radiation characteristics of semitransparent media containing bubbles or particles

“…Two approaches are usually proposed: the Far Field Approximation (FFA) [11][12][13] and the Near Field Approximation (NFA). [14][15][16][17][18][19] The FFA was initially developed by Mundy et al 11 and Chylek 12 by extending the classical Mie theory (CMT), 7 i.e., particle in non-absorbing environment to particle in an absorbing environment.…”