# Dual-channel high-speed functional photoacoustic microscopy with ultra-wide field of view

## TL;DR

A new dual-channel photoacoustic microscope captures large areas quickly and clearly, enabling detailed studies of whole organs or bodies in live animals.

## Contribution

DC-PAM introduces a dual-channel design that achieves ultra-wide field of view without sacrificing speed or resolution.

## Key findings

- DC-PAM achieves an ultra-wide FOV of 22.5 × 24 mm² with ~15 s functional imaging time.
- Proof-of-concept experiments show DC-PAM's utility in tracking physiological processes in zebrafish, mice, and glassfrogs.
- The system supports whole-organ and whole-body imaging in freely moving or active animals.

## Abstract

Photoacoustic microscopy (PAM) systems often face challenges in simultaneously achieving high speed, high resolution, high sensitivity, and a large field of view (FOV). To address this challenge, we have developed dual-channel PAM (DC-PAM) that can expand the FOV without compromising the imaging speed, detection sensitivity, or spatial resolution. DC-PAM has two identical, independent channels of laser excitation and acoustic detection. It exploits two facets of a single hexagon scanner to concurrently steer the dual excitation laser beams and the resultant acoustic waves. DC-PAM achieves an ultra-wide FOV of 22.5 × 24 mm² with a total functional imaging time of ~15 s. Proof-of-concept experiments were conducted using DC-PAM on freely-swimming zebrafish, hypoxia-challenged mice, and sleeping glassfrogs, all of which benefit from the large FOV and high imaging speed to track the dynamic and physiological processes at the whole-organ or whole-body level. These applications demonstrate the potential of DC-PAM for a wide range of biological studies.

Dual-channel photoacoustic microscopy (DC-PAM) enables ultra-wide-field, high-speed, and high-resolution imaging, advancing whole-organ and whole-body studies in freely moving or physiologically active animals.