Controlling light in scattering media noninvasively using the photo-acoustic transmission-matrix

TL;DR

This paper presents a novel non-invasive method to control and focus light inside scattering media by combining optical transmission-matrix measurement with photo-acoustic imaging, enabling deep-tissue applications.

Contribution

It introduces a new approach to measure the optical transmission-matrix non-invasively using the photo-acoustic effect, allowing simultaneous targeting and localization inside scattering media.

Findings

First non-invasive measurement of optical transmission-matrix in scattering media.

Ability to focus light on multiple targets simultaneously.

Potential for deep-tissue imaging and light delivery using endogenous contrast.

Abstract

Optical wavefront-shaping has emerged as a powerful tool to manipulate light in strongly scattering media. It enables diffraction-limited focusing and imaging at depths where conventional microscopy techniques fail. However, while most wavefront-shaping works to-date exploited direct access to the target or implanted probes, the challenge is to apply it non-invasively inside complex samples. Ultrasonic-tagging techniques have been recently demonstrated but these require a sequential point-by- point acquisition, a major drawback for imaging applications. Here, we introduce a novel approach to non-invasively measure the optical transmission-matrix inside a scattering medium, exploiting the photo-acoustic effect. Our approach allows for the first time to simultaneously discriminate, localize, and selectively focus light on multiple targets inside a scattering sample, as well as to recover and exploit the scattering medium properties. Combining the powerful approach of the transmission-matrix with the advantages of photoacoustic imaging opens the path towards deep-tissue imaging and light-delivery utilizing endogenous optical contrast.