Semiconductor quantum wells and superlattices are nanostructured metamaterials with nonlinear optical properties that can differ from those of the bulk semiconductors of which they are composed. In addition, it is possible to alter these properties on a spatially local scale by planar microstructuring techniques, such as quantum-well intermixing. Here, an example of these technologies is considered, the generation of optical second harmonic in a guided-wave environment, in which the nonlinear function is provided by a semiconductor superlattice and the quasi-phase-matching grating is synthesized by spatially selective quantum-well intermixing.
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