Super-resolution and frequency-dependent efficiency of near-field optical disks with silver nanoparticles

The super-resolution capability of the AgO_x-type super-resolution near-field structure disk with silver nanoparticles was studied using finite-difference time-domain method at different incident light frequencies. The near fields exhibited strongly local field enhancement around silver nanoparticles in the AgO_x layer due to localized surface plasmon. The subwavelength recording marks smaller than λ/10 were distinguishable since the metallic nanoparticles with high localized fields transferred evanescent waves to detectable signals in the far field. The far-field signals from random silver nanoparticles displayed similar behaviors as those from single nanoparticle and red-shifts of peak frequencies from particle-particle interaction.