Development of an Omnidirectional Optical System Based Photoacoustic Instrumentation

Abstract

We propose an omnidirectional optical system supported photoacoustic instrumentation in order to produce uniform intensity distributions in the panoramic field of view and low optical aberrations that covers 360 degrees in the horizontal plane. Because the photoacoustic instrumentation has commonly used the optical systems with limited field of view, additional mechanical movement systems with light sources had to be utilized to collect the target information. In order to verify the detection capability of the echo signal of the sample to cover the entire 360 degrees view in the horizontal plane, a typical pulse-echo photoacoustic instrumentation integrated with our developed omnidirectional optical system using blue light was tested. The maximum variances of the detectable echo signal amplitudes and their spectrum center frequencies were 2.33 mV and 1.59 MHz, which are acceptable variances for 10 MHz ultrasonic transducers. Therefore, the omnidirectional optical system supported photoacoustic instrumentation has a potential to produce the panoramic field of view and low optical aberrations, thus detecting echo signals in the entire +/-180 degrees range in the target without the mechanical movement systems.