Enhanced absorption of light by charged nanoparticles

Abstract

We found that various charged nanoparticles (NPs) can raise the attenuation of electromagnetic (EM) radiation over 30 times more efficiently during resonance in comparison to equivalent noncharged particles for a given set of parameters. A condition that indicates a state of resonance between the incident EM radiation and the NP surface excitations is mathematically derived. Our results shed light on the mechanism responsible for the strong absorption of light by such charged NPs. The outcome of this research could help to design a new generation of communication devices as well as a new technique for biological cell imaging.

Scattering of electromagnetic waves by charged spheres: near-field external intensity distribution

“…The differences found between the resonance behaviors of charged and electrically neutral particles have a mathematical foundation in the formula for scattering coefficient a n . As noticed in [8], a resonance occurs when the denominator of a n approaches zero, independent of whether it deals with near or far fields:…”

“…The far-field approximation was taken into account. Several applications of this approach also appeared in other fields of science [7][8][9][10].…”

Optical signatures of electrically charged particles: Fundamental problems and solutions

“…In a later case, we will demonstrate that one of the expansion coefficients a n can exceed all others including that for Rayleigh mode n ¼1. This is because σ s is a parameter that scales the above expansion coefficients and predetermines a mode of vibration that occurs when the denominator of the scattering coefficient is sufficiently small [12].…”

“…At present, the optical effects due to excess charges on a small particle or on a collection of small particles are largely unknown; however, they are of high importance for new technologies [8][9][10], for correct understanding of many physical processes [11], and for the revelation of new physical phenomena [12,13]. Specifically, the interstellar extinction features that are notoriously associated with material composition also may be affected by electric charge that acts as a modulator of the optical properties of small particles.…”

On the Scattering of Electromagnetic Waves by a Charged Sphere

“…(9) reduces to Eq. (26) given in [3] for the special case µ 1 = µ 0 (used also by Rosenkrantz and Arnon [9]). The conventional formulae for the Mie theory for electrically neutral particles follows from Eq.…”