# Nonradiative to Superscattering Switch with Phase-Change Materials

## TL;DR

This paper demonstrates a hybrid nanoantenna system using phase-change materials to achieve a large, reversible switch in scattering properties, enabling advanced active photonics with minimal energy input.

## Contribution

It introduces a novel hybrid metal-semiconductor nanoantenna design that leverages phase-change materials for significant and reversible scattering modulation.

## Key findings

- Achieves ~15x variation in total scattering
- Realizes ~100x change in forward scattering
- Predicts switching between Kerker and antiKerker scattering regimes

## Abstract

Phase-change materials (PCMs) can switch between different crystalline states as a function of an external bias, offering a pronounced change of their dielectric function. In order to take full advantage of these features for active photonics and information storage, stand-alone PCMs are not sufficient, since the phase transition requires strong pump fields. Here, we explore hybrid metal-semiconductor core-shell nanoantennas loaded with PCMs, enabling a drastic switch in scattering features as the load changes its phase. Large scattering, beyond the limits of small resonant particles, is achieved by spectrally matching different Mie resonances, while scattering cancellation and cloaking is achieved with out-of-phase electric dipole oscillations in the PCM shell and Ag core. We show that tuning the PCM crystallinity we can largely vary total (~15 times) and forward (~100 times) scattering. Remarkably, a substantial reconfiguration of the scattering pattern from Kerker (zero backward) to antiKerker (almost zero forward) regimes with little change (~5%) in crystallinity is predicted, which makes this structure promising low-intensity nonlinear photonics.

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Source: https://tomesphere.com/paper/1904.11442