Three-dimensional acousto-optic mapping using planar scanning with ultrasound bursts

We have investigated the application of AO sensing for quantitative three-dimensional mapping of tissue-mimicking phantoms. An Intralipid phantom, which contains a turbid absorber, confined in a silicone tube, was used. Multiply scattered pulsed laser light was modulated by ultrasonic bursts focused in a predefined volume in the medium. By varying the delay time between ultrasound burst initiation and light pulse firing we could perform a scan in the ultrasound-propagation plane. By moving the ultrasound transducer, we could build up a volumetric map of modulation depth values. We have experimentally determined the acousto-optical modulation depth as a function of the absorption coefficient in phantom voxels of a few millimeters in size.