Wavepacket Self-imaging and Giant Recombinations via Stable Bloch-Zener Oscillations in Photonic Lattices with Local ${\cal PT}$-Symmetry

TL;DR

This paper introduces a family of local PT-symmetric photonic lattices with a transverse index gradient, demonstrating stable Bloch-Zener oscillations, wavepacket self-imaging, and giant recombinations controlled by non-Hermiticity and impurities.

Contribution

It presents a novel class of local PT-symmetric photonic lattices that enable controlled stable Bloch-Zener oscillations and wavepacket recombination, enhanced by local impurities.

Findings

Stable Bloch-Zener oscillations occur under specific conditions between gradient and non-Hermiticity.

Wavepacket self-imaging and giant recombinations are achieved at various propagation distances.

Local impurities further enhance wavepacket recombination.

Abstract

We propose a family of {\it local} $\cal{PT}$-symmetric photonic lattices with transverse index gradient $\omega$, where the emergence of {\it stable} Bloch-Zener oscillations are controlled by the degree of non-Hermiticity $\gamma$ of the lattice. In the exact $\cal{PT}$-symmetric phase we identify a condition between $\omega$ and $\gamma$ for which a wavepacket self -imaging together with a cascade of splittings and giant recombinations occurs at various propagation distances. The giant wavepacket recombination is further enhanced by introducing local impurities.