Degradation of the second order optical nonlinearity in cubic media by straight dislocations

The influence of straight dislocations on the second order nonlinear optical susceptibility chi((2)) of cubic noncentrosymmetric media has been modeled. The resulting degradation of chi((2)) has been evaluated for screw and edge dislocations in GaAs. It is found that single screw and edge dislocations reduce the chi((2)) of GaAs by a third and similar to 60%, respectively. This implies that second order nonlinear optical effects are very sensitive to misfit dislocation generation in epitaxially grown noncentrosymmetric media and that dislocation-free epilayers are required to realize the optimum chi((2)). (C) 1995 American Institute of Physics.