Center for Relativistic Laser Science

2019 Light in Complex Materials WORKSHOP

For non-invasive optical imaging, sensing, and stimulation of target objects embedded deep within a scattering medium, it is essential to deliver light waves to target objects efficiently. However, multiple light scattering induces random wave diffusion and drastically limits the light waves reaching the target object. Here, we present a method to focus multiple-scattered waves at the deeply embedded target. We experimentally identified and injected light to the time-gated reflection eigenchannel which preferably enhances the reflection of multiple-scattered waves that have interacted with the target object. For targets not resolved by optical imaging, we achieved more that 10-fold enhancement in light energy delivery compared to uncontrolled inputs. Furthermore, we derived an analytic expression describing the way the eigenchannel coupling of the total reflection preferably enhances the target interacted reflection. This work provides a foundation for enhancing the working depth of optical methodologies and a new analytic framework for understanding the effect of wavefront shaping in the control of wave propagation in disordered media.