Optical-resolution confocal photoacoustic microscopy

A confocal photoacoustic microscope with improved lateral resolution has been developed by employing stronglyfocused bright field optical illumination and spherically focused 75-MHz ultrasonic detection. The lateral resolution was experimentally measured to be 5 μm and the axial resolution was estimated to be 15 μm. The maximum imaging depth was demonstrated to be greater than 0.7 mm. In in vivo experiments, microvessels with a diameter of ~ 5 μm are imaged in small animals.