  From the earth's crust to the human brain, remitted waves are used for
sensing and imaging in a diverse range of diffusive media. Separating the
source and detector increases the penetration depth of remitted light, yet
rapidly decreases the signal strength, leading to a poor signal-to-noise ratio.
Here, we experimentally and numerically show that wavefront shaping a laser
beam incident on a diffusive sample enables an order of magnitude remission
enhancement, with a penetration depth of up to 10 transport mean free paths. We
develop a theoretical model which predicts the maximal-remission enhancement.
Our analysis reveals a significant improvement in the sensitivity of remitted
waves, to local changes of absorption deep inside diffusive media. This work
illustrates the potential of coherent wavefront control for non-invasive
diffuse-wave imaging applications, such as diffuse optical tomography and
functional near-infrared spectroscopy.
