Super-resolution technologies for ultrahigh-density optical data storage are described. Applying optical nonlinear thin films, super-resolution readout is attained in less than the optical diffraction limit. In combination with near-field principle, it is further improved in less than 100 nm. In this paper, we discuss the basic principle of near-field optic and related surface and localized surface plasmon polaritons at first, and discribe several applications with metallic nanoparticles and wires to future optical disk technology.