Holographic Ultrasound Laser Optical Tomography – HULOT

Optical imaging of small objects (inferior to mm) in a highly scattering environment becomes increasingly challenging with imaging depth (cm to meter range). It would lead to disruptive innovations for in-situ characterization, e.g. non-destructive control, turbid media (pollutant detection, …), or medical imaging. Acousto-Optic Imaging (AOI) is a multimodal technique based on the interaction between light and ultrasound (US) at a given depth. AOI faces limited flux collection and sub-ms instabilities speckle in a dynamic environment, thereby imposing short acquisition times. In HULOT, we propose a new instrumentation chain which addresses both of these bottlenecks including key innovations, with a fully programable ultrasound scanner and a new powerful laser source working in a quasi continuous regime (ideally 100W during 100 microseconds). The latter will be tunable in wavelength in the deep red, its temporal width will enable to dispose of a high power during the correlation time of instabilities. We will add a spatio-temporal shaping of the US and light in order to increase the volume of light tagged by the US, detected by CMOS camera-based sensors. An improvement of two orders of magnitude in detection efficiency is expected and will open new perspectives for imaging and characterization of these complex media.