Optical-resolution photoacoustic microscopy by use of a multimode fiber

TL;DR

This paper introduces a method for optical-resolution photoacoustic microscopy using a multimode fiber and digital phase conjugation, enabling high-resolution imaging through a miniature fiber-based system.

Contribution

It demonstrates a novel approach combining multimode fibers and digital phase conjugation for high-resolution photoacoustic imaging.

Findings

Achieved sub-1.5μm resolution in photoacoustic imaging.

Successfully scanned a 201μm by 201μm field of view.

Showed potential for miniature endoscopic imaging systems.

Abstract

We demonstrate Optical-Resolution Photoacoustic Microscopy (OR-PAM), where the optical field is focused and scanned using Digital Phase Conjugation (DPC) through a multimode fiber. The focus is scanned across the field of view using digital means, and the acoustic signal induced is collected by a transducer. Optical-resolution photoacoustic images of a knot made by two absorptive wires are obtained and we report on resolution smaller than 1.5{\mu}m across a 201{\mu}m by 201{\mu}m field of view. The use of a multimode optical fiber for the optical excitation part can pave the way for miniature endoscopes that can provide optical-resolution photoacoustic images at large optical depth.