Transient effects at resonant light scattering by particles: Anapole as a storage for "frozen light"?

TL;DR

This paper investigates the transient behavior of anapole modes in high-Q resonant scattering, revealing that they cannot serve as stable storage for frozen light due to rapid decay after excitation ceases.

Contribution

It provides analytical and numerical analysis of anapole modes, showing their nonequilibrium nature and transient existence only under continuous illumination.

Findings

Anapole modes are steady only under continuous wave excitation.

Once the incident wave stops, the anapole quickly radiates away its energy.

Anapole modes cannot be used as stable light storage due to rapid decay.

Abstract

Transient effects at excitation of high-Q resonant modes at a leading front of a laser pulse and their decomposition at its trailing edge during the pulse scattering by a particle are discussed. The main attention is paid to the nonradiating (anapole) mode excited in a high-index cylinder. The problem is studied both analytically and numerically. It is shown that the anapole is a steady but essentially nonequilibrium mode, which can exist if and only if the host particle is irradiated by a continuous incident wave. As soon as the incident wave is switched off the anapole becomes a radiating mode and collapses very fast owing to extensive radiative losses. It ruins the hopes to employ the anapole-like excitations as storages for the "frozen light."