We propose and experimentally verify a method to program the effective transmission matrix of general multiport linear optical circuits in random multiple-scattering materials by phase modulation of incident wavefronts. We demonstrate the power of our method by programming linear optical circuits in white paint layers with 2 inputs and 2 outputs, and 2 inputs and 3 outputs. Using interferometric techniques we verify our ability to program any desired phase relation between the outputs. The method works in a deterministic manner and can be directly applied to existing wavefront-shaping setups without the need of measuring a transmission matrix or to rely on sensitive interference measurements.
Huisman, S. R., Huisman, T. J., Wolterink, T. A. W., Mosk, A. P., & Pinkse, P. W. H. (2015). Programmable multiport optical circuits in opaque scattering materials. Optics express, 23(3), 3102-3116. https://doi.org/10.1364/OE.23.003102