Quasi-phase matched nonlinear media: Progress towards nonlinear optical engineering

Nonlinear optics has been enabled by the invention of the laser 50 years ago, and since then both technologies evolved together complementing and enabling each other. In this paper we attempt to briefly overview the historic development of second-order nonlinear materials and try to discern the trends which might dominate developments in the future. The advent of methods of quasi-phase matching and added degrees of freedom in managing three-wave mixing processes pushed the field of nonlinear optics into the realm of engineering. This trend, we believe will continue in the future. In this text we give a short description of design principles of one-dimensional and two-dimensional quasi-phase matched structures and emphasize the increased functionality afforded by such structures. We also overview the nonlinear media where engineering of nonlinear interactions has been demonstrated with the primary focus on ferroelectric and semiconductor nonlinear crystals.

► We overview the development of nonlinear crystals over last 50-years.
► We attempt to discern the directions of the future development.
► We conclude that engineered nonlinear materials might be dominant in the future.