The cochlea seen as an active metamaterial

Image

Fabrice Lemoult 

Le 24 janvier 2023 de 11h00 à 12h00 / Amphithéâtre François Canac, LMA

Abstract : The human ear is a fascinating sensor, capable of detecting a range of sounds covering ten octaves in frequency and twelve orders of magnitude in amplitude. These exceptional properties are the result of non-linear phenomena that occur within the cochlea, the organ of the inner ear responsible for the conversion of sound stimuli into nerve impulses. The understanding of such mechanisms is both a fundamental challenge and an opportunity to improve the performance of microphones.

In this presentation, we transpose results obtained in the field of acoustic metamaterials to the context of hearing. With the help of a device consisting of a succession of resonant tubes of increasing heights, we experimentally reproduce an analogue of the cochlear response. But, what is fascinating in the biology of the cochlea is precisely its living character. To mimic this property, we have in a way animated metamaterial, by adding in each resonator a feedback loop. The results show that our artificial cochlea qualitatively reproduces the behavior of a biological one.

Fabrice Lemoult / ESPCI