Combined optical- and acoustic-resolution photoacoustic microscopy based on an optical fiber bundle

Abstract

Photoacoustic microscopy (PAM), whose spatial resolution and penetration depth are both scalable, has made great progress in recent years. According to their different lateral resolutions, PAM systems can be categorized into either optical-resolution (OR) PAM, with optical-diffraction-limited lateral resolution, or acoustic-resolution (AR) PAM, with acoustically limited resolution and a deeper maximum imaging depth. In this report, we present a combined OR and AR PAM system with resolutions of 2.2 μm and 40 μm, respectively. Sharing most components between the OR and AR implementations, the system achieves separated illumination for OR and AR imaging by an optical fiber bundle through different channels, and two discrete lasers are used to provide either high-power energy for AR imaging or highrepetition- rate pulses for OR imaging. The design enables automatically co-registered OR and AR photoacoustic imaging in one single system, which extends the usability of current photoacoustic systems and simplifies the imaging procedure.