We developed an all-optical 3D photoacoustic imaging probe consisting of an optical fiber probe for ultrasound detection and a bundle of hollow optical fibers for excitation of photoacoustic waves. The fiber probe for ultrasound is based on a single-mode optical fiber with a thin polymer film attached to the output end surface that works as a Fabry Perot etalon. The input end of the hollow fiber bundle is aligned so that each fiber in the bundle is sequentially excited. A thin and flexible probe can be obtained because the probe system does not have a scanning mechanism at the distal end.
An optical fiber ultrasound probe for all-optical photoacoustic endoscopy imaging is developed. The probe has a Fabry Perot interferometer consisting of a polymer film attached at the end surface of a single-mode optical fiber. The interferometer detects acoustically-induced pressure change in the optical thickness and transforms the change into output optical power. Experimental results show that the probe functions well as a photoacoustic probe and the SNR is comparable to that of a PVDF hydrophone. Results for B-mode imaging of blood vessel phantom taken by using the fiber probe are also shown.