Thermoacoustic tomography using fiber based Fabry-Perot interferometer as an integrating line detector

Thermoacoustic tomography is based on the generation of acoustic waves by a bulk illumination of a sample with a short electromagnetic pulse. The thermal expansion of the sample generates acoustic waves. The absorption density inside the sample is reconstructed from the acoustic pressure signals measured outside of the sample. So far signals have been collected with small detectors that approximate point-detectors. In the present study we report on a novel measurement setup applying integrating detectors. With these detectors the pressure is integrated along one or two dimensions. This enables the use of numerically efficient algorithms, such as the inverse Radon transformation, for thermoacoustic tomography. To reconstruct a three-dimensional image, either a two-dimensional integrating detector has to be moved tangentially around a sphere enclosing the object or an array of line-detectors has to be rotated around a single axis. Implementations of line-detectors are demonstrated that are adaptations of a Fabry-Perot interferometer. As a novel approach for the implementation a Fabry-Perot interferometer consisting of a single mode fiber is demonstrated.