Nonlinear near-field optical effects of the AgOx-type super-resolution near-field structure

Super-resolution near-field structure (Super-RENS) was introduced by Tominaga et al. (1998) to perform the task of near-field recording in a more feasible way. Super-RENS has the advantages of simpler recording head design, less mechanic damage, and higher recording speed. Our previous research has shown that the collective effects of the localized surface plasmon and the heterogeneous material structure are responsible for the unusual optical property of the Super-RENS. To further explore the nonlinear near-field optical property of the Super-RENS, we studied direct near-field optical images and two-dimensional finite-difference time-domain (FDTD) simulations of the AgO_x super-RENS. Our results provide a direct connection between the surface plasmon effects of silver nanoparticles and nonlinear near-field optical property observed in experiments.