# Morphogenesis of sound creates acoustic rainbows

## TL;DR

This paper shows how to design energy-efficient structures that split sound into its components, inspired by natural sound manipulation.

## Contribution

The novel use of computational morphogenesis to create an efficient acoustic rainbow structure and wavelength splitter.

## Key findings

- Acoustic rainbow structures with 'above unity' efficiency were designed using computational morphogenesis.
- A wavelength-sized, single-material sound splitter was developed for spatio-spectral decomposition.
- The approach enables passive sound manipulation without active transduction.

## Abstract

Sound is a crucial sensing element for many organisms in nature, with various species evolving organic structures that produce complex acoustic scattering and dispersion phenomena to emit and perceive sound clearly. To date, designing artificial scattering structures that match the performance of these organic structures has proven challenging. Typically, sound manipulation relies on active transduction in fluid media rather than passive scattering principles, as often observed in nature. In this work, we use computational morphogenesis to create complex, energy-efficient, wavelength-sized single-material scattering structures that passively decompose radiated sound into its spatio-spectral components. Specifically, we design an acoustic rainbow structure with “above unity” efficiency and an acoustic wavelength splitter. Our work demonstrates what is possible when using computational morphogenesis to tailor the emission and reception of sound fields, with relevance to disciplines concerned with the sensing and emission of wave fields.

An acoustic rainbow is realized using computational morphogenesis, enabling energy-efficient spatio-spectral decomposition sound.