Nonlinear optical patterns: applications to spatial soliton arrays, quantum aspects

In this article we discuss two aspects of nonlinear optical patterns. The first concerns the possibility of a future application to information processing, based on the realization of arrays of spatial soliton pixels in broad area semiconductor microcavities. We outline the concepts, the control and the perspectives. The second aspect concerns the quantum features of nonlinear optical patterns. We discuss the concept of quantum image in the framework of parametric down-conversion processes. Numerical simulations show the transition from a quantum image to a classical image across the threshold region of a degenerate optical parametric oscillator. An experiment with lithium triborate shows strikingly similar results in both the near and the far field, displaying qualitatively the classical features of quantum images.