Histogram analysis of photoacoustic effect changes on different liquid samples

The photoacoustic imaging is based on the effect of the acoustic response of laser light absorption to avoid the effects of light scattering. The photoacoustic imaging shows the outperformance to compare with traditional ultrasound imaging. However, it is unknown if the photoacoustic effect changes when the laser misalignment on the reticulated piezoelectric ceramic. Our system is mainly composed of hardware and software, including a piezoelectric ceramic, motors, a class III laser diode, relays, and a data acquisition card combined with LabView program. The piezoelectric sensor is a 21.9mm by 15.9mm rectangular ceramic with four strip holes in the center. The laser hits several different spots on strip holes of piezoelectric. The total of 6 points are tested to observe if these signals keep consistence. The results demonstrated the laser mis-alignment effect of photoacoustic imaging can be controlled. Finally, the research tested different samples and analyzed by histogram method to obtain the response signals with different features. This research may help to generate photoacoustic features faster and to improve image quality in the future.