Optical computing using nonlinear optical diffraction

We present a single-layer optical inference system based on nonlinear optical diffraction. In this system, input optical data is superposed with control parameters and then focused into a nonlinear optical crystal leading to second harmonic generation which serves as the output of the system. We demonstrate image classification while utilizing a very low number of degrees of freedom. Importantly, the performance of the system can be tuned by controlling the level of spatial mode mixing in the nonlinear crystal.