Multiple quantum wells for PT-symmetric phononic crystals

TL;DR

This paper demonstrates the realization of PT-symmetry in phononic crystals using laser-pumped quantum wells, leading to highly selective acoustic amplification and predicted phonon lasing.

Contribution

It introduces a novel approach to achieve PT-symmetry in sound waves via quantum-well structures, enabling new phononic device functionalities.

Findings

PT-symmetry is realized in laser-pumped quantum wells.

Breaking PT-symmetry results in selective acoustic wave amplification.

Single-mode phonon lasing is predicted with realistic parameters.

Abstract

We demonstrate that the parity-time symmetry for sound is realized in the laser-pumped multiple-quantum-well structure. Breaking of the parity-time symmetry for the phonons with wave vectors corresponding to the Bragg condition makes the structure a highly-selective acoustic wave amplifier. Single-mode distributed feedback phonon lasing is predicted for structures with realistic parameters.