Non-linear optical properties of the Ag nanoparticles on the ITO

The second-order optical properties of silver (Ag) nanoparticles (NP) on the ITO substrates of different resistance are investigated. The photoinduced effect at 1.32 μm demonstrates a marked dependence of the photoinduced optical SHG versus the Ag NP sizes. Particularly, it was shown that there exist a maximum of the SHG for the interparticle distance about 124 nm corresponding to about 35 nm.Comparison with the photoinduced effects in the Ag NP on the glass and with the ITO substrate indicates on a crucial role of the Ag NP/ITO interfaces in the observed dependences. The effect may be a consequence of the interface localized trapping levels creating a great number of effective centers, which stimulate an occurrence of the SHG signal. The maximally achieved second-order optical susceptibility at 1.32 μm wavelength corresponds to the value of about 6.37 pm/V.