Photoacoustic spectrum analysis for microstructure characterization using ultra-broad bandwidth optical ultrasonic detector

Photoacoustic spectrum analysis (PASA) has been found to have the ability to characterize microstructures in phantoms. The ability of PASA technique which is subjected to the ultrasound detector has been reported in identify tissue with hundreds of microns in size. This paper demonstrated the feasibility of micro-ring, an ultrasonic detector with ultra-broad bandwidth, in characterizing microspheres’ sizes ranging from few microns to 100 microns using PASA technique and the results were compared with a commercial hydrophone. In order to further verify the capability of micro-ring, spectrum of single micro-spheres with sizes of tens of microns were measured and compared to simulation result. Our work proves that micro-ring based PASA technique has the ability of differentiating the particles with different size in phantoms.