Synthetic topological device for advancing elastic energy harvesting

TL;DR

This paper introduces a synthetic higher-order topological insulator in elastic metamaterials that enables highly localized hinge states, significantly improving elastic energy harvesting and energy conversion efficiency for advanced ultrasonic devices.

Contribution

It presents a novel synthetic-dimensional topological insulator with localized hinge states, enhancing elastic-to-electric energy conversion in elastic metamaterials.

Findings

Demonstrated robust localized hinge modes through simulations and experiments.

Achieved efficient elastic-to-electric energy conversion activating LEDs.

Opened new pathways for ultrasonic device applications and self-powered sensors.

Abstract

High-efficiency energy harvesting of ultrasonic elastic waves are crucial for powering electric gadgets in many emerging technologies such as wearable devices, wireless sensing, and biomedical implants. Although topological phononic metamaterials have recently been demonstrated as a promising paradigm for confining and guiding elastic waves through robust bound states, achieving ultrahigh-Q topological resonance with enhanced energy conversion efficiency remains a challenge. In this work, we propose a synthetic-dimensional higher-order topological insulator by engineering the flexural bands of elastic metamaterials, featuring highly localized topological hinge states in the bulk bands. This topological hinge mode stems from the nonzero combination of the bulk polarization and the Chern number in the synthetic-dimensional band structure, thus giving rise to a strong elastic-to-electric energy conversion at the corner of the phononic plate. Through numerical simulations and experimental validations, straightforward evidence of the localized modes with robust protection and consequent abilities in activating the light-emitting diodes (LEDs) array have been demonstrated. Our findings open a new avenue for topological-physics-enabled ultrasonic devices and present promising prospects for applications in weak-signal detection and self-powered sensors.