Reflection-mode optical-resolution photoacoustic microscopy with high detection sensitivity by using a perforated acoustic mirror

Abstract

Detection sensitivity is one key factor determining the performance of an optical-resolution photoacoustic microscopy (OR-PAM) system. High detection sensitivity means a higher signal-to-noise ratio, cleaner images, and better biological safety. We demonstrate a reflection mode OR-PAM with high detection sensitivity by using a flat perforated acoustic mirror and a commercial focused ultrasound transducer. The proposed optical-acoustic combiner can provide optical-acoustic confocal alignment on the same side of the sample, low acoustic insert loss, and an undistorted optical path. Experimental measurements demonstrated its detection sensitivity and imaging quality. Finally, the real practical performance of this system was preliminarily examined by in vivo imaging of the capillaries in the ear of nude mice and the nevus on a volunteer's hand. Therefore, benefitting from the proposed design and the fine balance between sensitivity, resolution, reflection mode, and ease of implementation, the proposed system might have valuable biomedical applications.