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

The super-resolution capability of the AgOx-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 AgOx 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.