Optical evolution of dislocation speckle imaging inside and outside of thin films

We have employed a fiber scanning probe microscopy to study light localization due to multi-scattering of light by dislocation defects in III-V films (in particular, GaAs-Si). By sputtering the film down to the semiconductor-substrate interface we observe how the nonlinear optical signature of the dislocation defects changes with the increasing density of a dislocation area. The same probe microscopy approach was used to track the evolution of the propagating optical fields from these dislocation speckles, outside the thin film. Such approach can be used as an extremely high resolution monitoring tool of propagating electromagnetic fields.