Abstract

Acoustic line detectors have been shown to be capable of providing accurate signals for three-dimensional photoacoustic tomography. Free and guided beam optical Mach-Zehnder interferometers (MZI) have been used as well as a waveguide Fabry-Perot interferometer (FPI). The ultimate sensitivity is expected from a FPI where the optical field in the resonator propagates in the acoustic coupling medium (water) surrounding the imaged object. Such a free-beam FPI is completely optically and acoustically transparent, while providing a higher sensitivity compared to the MZI due to the multiple beam interference. In this work the performance of a FPI for measurement of ultrasound waves is compared to a MZI. It is shown that an at least 4.5-fold higher signal to noise ratio is achieved compared to a MZI. The resolution of the FPI is simulated and measured, showing a constant diameter of the interferometer beam. Verification of the stability of the free beam FPI over longer time periods is demonstrated by acquiring a two-dimensional tomography image of a phantom. The sensitivity and stability of the setup makes it suitable for tomographic imaging.

© 2013 SPIE