Combined confocal and photoacoustic microscopy based on probe beam deflection technique

摘要

A device for acquiring co-registered reflectance confocal microscopy (RCM) and optical-resolution photoacousticmicroscopy (OR-PAM) images is presented. It uses a pulsed laser for photoacoustic excitation and a continuous laser forthe confocal mode, co-aligned, focused and scanned over planes within the object. The photoacoustic part uses a probebeam deflection method, where a continuous laser beam is bent in the refractive index gradient generated by the pressurewave. First images on a carbon microfiber phantom demonstrate the capability of generating co-registered images, wherethe RCM mode displays back-scattering contrast, while the OR-PAM mode creates images with optical absorptioncontrast. In the temporal signals of both methods, typical signatures of transient cavitation were visible in the carbonfiber experiment. A lateral resolution of the setup of about 1.6 μm and a noise equivalent pressure amplitude of 90 Pa forthe probe beam deflection method were measured.