Second-harmonic generation from realistic film–substrate interfaces: The effects of strain

The optical second-harmonic generation from a thin crystalline film on a substrate is theoretically investigated for both s and p polarized incident light. The contributions of lattice misfit strain as well as of misfit dislocation strain to the second-order nonlinear optical susceptibility are described using a nonlinear photoelastic tensor and can be separated by a polarization analysis of the scattered light at the second harmonic frequency. For the s(v)→s(2v) and p(v)→s(2v) scattering geometries, the nonlinear optical signal will be determined by dislocation strain only, whereas for the s(v)→p(2v) and p(v)→p(2v) geometries both lattice misfit strain and misfit dislocation strain will contribute. © 2000 American Institute of Physics. @S0003-6951~00!01814-3#