分野別セミナー

A detailed inspection of light scattering by a particle with high refractive index m+iκ and small dissipative constant κ is presented. It is shown that there is a dramatic difference in the behavior of the electromagnetic field within the particle (inner problem) and the scattered field outside it (outer problem). With an increase in m at fix values of the other problem parameters the field within the particle asymptotically converges to a periodic function of m. The electric and magnetic type Mie resonances of different orders overlap substantially. It may lead to a giant concentration of the electromagnetic energy within the particle. At the same time, it is demonstrated that identical transformations of the solution to the outer problem allow to present each partial scattered wave as a sum of two partitions. One of them corresponds to the m-independent wave, scattered by the perfectly reflecting particle, while the other is associated with the excitation of a sharply-m-dependent resonant Mie mode. The interference of the partitions brings about a typical asymmetric Fano profile. At an increase in m, in contrast to the inner problem, the resonant modes of the outer problem die out, and the scattered field converges to the universal, m-independent profile. The behavior of the resonances at a fixed m and varying particle size parameter (x) is also examined in detail. The similarities and differences of the two cases (fixed x – varying m and fixed m - varying x) are disclosed. The relevant experiments are discussed.

リンク:セミナーHP