Near-field optical diagnostics of nanoparticle structure buried within single dielectric layer

The near-field response of optically excited nanoparticle structure buried within thin dielectric layer is theoretically and numerically studied for the illumination and collection modes of a scanning near-field optical microscopy. As the probe we consider a single dipole-like particle that scans the surface of the sample. Nanostructure is modeled as a finite-size periodic array of dipole-like particles, the size of the structure is assumed to be much smaller than the wavelength of the external electromagnetic wave. The electromagnetic signal in a remote detector is proportional the time-average energy flux of the scattered probe field. For the determination of the field in the system the dyadic Green's function of the one layer system is used in the unretarded approximation. We have found that field distribution and the magnitude of the field intensity in the system strongly depend on the polarization of the exciting external waves and the inter-particle distances in the nanostructure. The near field distribution in the system under condition of local plasmon resonance, when the polarizability of every particle in the nanostructure was significantly increased, is also considered.