An Idea for Measuring Spatial Coherency Matrices by Multiplexing Across a Reconfigurable Complex System onto a Single-Port Intensity Detector

We propose a technique for measuring the spatial coherency matrix of a wavefront based on a single-port intensity detector. Our method relies on multiplexing the incident wavefront across a series of known realizations of a reconfigurable complex system onto the intensity detector. We consider a multi-port chaotic cavity with partially reconfigurable boundary conditions as an embodiment of the reconfigurable complex system. This matches recent experiments with 3D chaotic cavities whose walls are partially covered with a programmable metasurface. We formulate a system model that rigorously accounts for multiple scattering based on multi-port network theory. Then, we numerically validate the principle. The appeal of our technique lies in the low hardware complexity.