Structural studies of silver island films probed by hyper-Rayleigh scattering and atomic force microscopy

The effect of incoherent optical second-harmonic generation (hyper-Rayleigh scattering, HRS) in silver island films is studied in combination with the scanning atomic force microscopy (AFM) of these films. The interpretation of the obtained experimental results is based on comparison of two types of correlation functions: (i) the density–density correlation function derived from the AFM images of the film surface and (ii) the correlation functions of the surface polarization fluctuations calculated by the inverse Fourier transform of the HRS and Rayleigh (linear) scattering (RS) indicatrices. In-plane correlations in the polarization fluctuations responsible for HRS and RS are found to decay at larger distances than correlations in fluctuations of the surface concentration of the islands. This means that the shape of HRS and RS indicatrices is significantly affected by the long-range electromagnetic interaction between the islands.