Abstract

We present an approach to optimally move a specific scatterer in a multiple scattering medium, by pushing it using engineered wavefronts to guide it along a pre-defined trajectory. This is particularly challenging when the object to be moved modifies significantly the speckle field as it moves, or in other words, when it does not scatter much more than the other particles in the medium. Our method is based on real-time far-field measurements that allow us to determine the optimal wavefront to push the object in a given direction. A proof-of-concept experiment using audible sound will be presented, demonstrating the use of the method to push or rotate a floating object in a parallel plate acoustic waveguide. A conclusion will be given about the possible extension of the concept to ultrasonic frequencies and applications in biological tweezer for micromanipulation in scattering and even time-dependent media