Focusing on Nonlinear Targets Embedded in a Complex Environment

In the microwave regime, electronic devices typically couple nonlinearly with the electromagnetic field. It is then possible to design approaches to detect and/or focus on targets based on their nonlinear interaction with an incoming wave. Here, we build up on a recent technique based on the measurement of a monochromatic scattering matrix at two different incident power. This noninvasive method has been used to focus waves on a single nonlinear target embedded in a chaotic microwave cavity. Here, we extend this work for the case of multiple targets located in a complex environment. We show that we are able to extract wavefronts that focus selectively on each of the targets. Additionally, we tune a disordered system through a reconfigurable metasurface to enhance the intensity received by a nonlinear target over a chosen wide range of frequency.