Virtual acoustics in inhomogeneous media with single-sided access

TL;DR

This paper presents a method using complex focusing functions to create virtual acoustic sources and receivers inside inhomogeneous media with access from only one side, enabling accurate wave response predictions for imaging and monitoring.

Contribution

It introduces an experimental design for virtual acoustics in inhomogeneous media with single-sided access, overcoming limitations of traditional time-reversal methods.

Findings

Successfully created virtual sources and receivers inside media

Predicted complex wave responses without detailed medium models

Potential applications in medical imaging and earthquake monitoring

Abstract

A virtual acoustic source inside a medium can be created by emitting a time-reversed point-source response from the enclosing boundary into the medium. However, in many practical situations the medium can be accessed from one side only. In those cases the time-reversal approach is not exact. Here, we demonstrate the experimental design and use of complex focusing functions to create virtual acoustic sources and virtual receivers inside an inhomogeneous medium with single-sided access. The retrieved virtual acoustic responses between those sources and receivers mimic the complex propagation and multiple scattering paths of waves that would be ignited by physical sources and recorded by physical receivers inside the medium. The possibility to predict complex virtual acoustic responses between any two points inside an inhomogeneous medium, without needing a detailed model of the medium, has large potential for holographic imaging and monitoring of objects with single-sided access, ranging from photoacoustic medical imaging to the monitoring of induced-earthquake waves all the way from the source to the earth's surface.