Non-contact Photoacoustic Tomography using holographic full field detection

An innovative very fast non-contact imaging technique for Photoacoustic Tomography is introduced. It is based on holographic optical speckle detection of a transiently altering surface topography for the reconstruction of absorbing targets. The surface movement is obtained by parallel recording of speckle phase changes known as Electronic Speckle Pattern Interferometry. Due to parallelized 2-D camera detection and repetitive excitation with variable delay with respect to the image acquisition, data recording of whole volumes for Photoacoustic Imaging can be completed in times far below one second. The size of the detected area is scalable by optical magnification. As a proof of concept, an interferometric setup is realized, capable of surface displacement detection with an axial resolution of less than 3 nm. The potential of the proposed method for in vivo Photoacoustic Imaging is discussed.