Phase diagram to design passive scatterers
Jeng Yi Lee1*, Ray-Kuang Lee1
1光電工程研究所, 國立清華大學, 新竹, Taiwan
* presenting author:Jeng Yi Lee,
We study phase and amplitude of scattering coefficients for single passive scatterers. The scattering coefficient is not only related to characteristic cross sections but also connects extrinsic state of scattered field. Owing to physical law of power conservation, it results in the existence bounds on phase and amplitude for this coefficient, showing its non-trivial physical connotation and further clearly displaying competition among scattered and absorbed powers. Exotic scattering and absorption phenomena, from resonant scattering, invisible cloaking, coherent perfect absorbers, and subwavelength superscattering can be illustrated in this phase diagram. We take an electrically small core shell composite structure as an example, illustrating the use of this phase diagram. Furthermore, using arbitrary allowed locus, or related geometry and material dispersive relation through impinging frequency, the diagram can give complete information, further highlighting the controllable scattering and absorption of light-matter interaction. This phase map may provide a simple tool to design optical devices and may promote the fundamental understanding of Mie's scattering theory.

Keywords: Mie theory, phase diagram, invisible cloaking, resonant scattering, coherent perfect absorber