Comprehensive Model for Randomly Phase-Matched Frequency Conversion in Zinc-Blende Polycrystals and Experimental Results for ZnSe

With their natural randomness, polycrystalline materials as gain elements have opened an avenue for the development of ultrafast laser sources. The authors' model, based on the rigorous orientation of crystalline domains, lays the foundation for ultrafast three-wave interactions in a material, in terms of randomized polarizations and intensities. This work clarifies the potential of random phase matching in ultrafast applications, as well as the standard for nonlinear gain in this process, by comparison to the well-developed technology of quasi-phase matching.