ABSTRACT
The purpose of this chapter is to review recent developments in engineered optical materials, and in
particular nonlinear crystals. This definition can be taken to mean conventional materials that are
structurally altered to give new and enhanced optical properties. To distinguish such materials from
other structured materials such as doped semiconductors or countless other examples, we will also limit
the definition to mean only those that are noncentrosymmetric. Thus it includes periodically poled
ferroelectrics and polar crystals. The materials covered in this chapter are ones that were mostly
developed for their nonlinear optical properties, but are now seeing applications in other areas of optics
such as electro-optics. This review is written for the general laser scientist who wishes to learn more
about what can be achieved with these materials, and not for those specialists already working in quasi-
phase matched (QPM) materials.
