title: Fiber-optic annular detector array for large depth of field photoacoustic macroscopy.
abstract: We report on a novel imaging system for large depth of field photoacoustic scanning macroscopy. Instead of commonly used piezoelectric transducers, fiber-optic based ultrasound detection is applied. The optical fibers are shaped into rings and mainly receive ultrasonic signals stemming from the ring symmetry axes. Four concentric fiber-optic rings with varying diameters are used in order to increase the image quality. Imaging artifacts, originating from the off-axis sensitivity of the rings, are reduced by coherence weighting. We discuss the working principle of the system and present experimental results on tissue mimicking phantoms. The lateral resolution is estimated to be below 200 μm at a depth of 1.5 cm and below 230 μm at a depth of 4.5 cm. The minimum detectable pressure is in the order of 3 Pa. The introduced method has the potential to provide larger imaging depths than acoustic resolution photoacoustic microscopy and an imaging resolution similar to that of photoacoustic computed tomography.
authors.affiliation: Research Center for Non-Destructive Testing GmbH (RECENDT), Altenberger Straße 69, 4040 Linz, Austria.
authors.forename: Johannes
authors.initials: J
authors.lastname: Bauer-Marschallinger
authors.affiliation: Research Center for Non-Destructive Testing GmbH (RECENDT), Altenberger Straße 69, 4040 Linz, Austria.
authors.forename: Astrid
authors.initials: A
authors.lastname: Höllinger
authors.affiliation: Institute for Microelectronics and Microsensors, Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Jakoby
authors.affiliation: Research Center for Non-Destructive Testing GmbH (RECENDT), Altenberger Straße 69, 4040 Linz, Austria.
authors.forename: Peter
authors.initials: P
authors.lastname: Burgholzer
authors.affiliation: Research Center for Non-Destructive Testing GmbH (RECENDT), Altenberger Straße 69, 4040 Linz, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Berer
keywords: Fiber-optics imaging; Interferometry; Optical ultrasound detection; Photoacoustic imaging; Photoacoustic macroscopy