Evanescent light enhancement in a nanometer aperture surrounded by corrugated metal thin film for a terabyte optical disk head

An ultrahigh density optical disk head which utilizes evanescent light (near-field light) had been designed to enhance the near-field optical wave for the throughput increment using the surface plasmon polariton resonance effect between the light inside the near-field optical head and nano-fabricated corrugated metal thin film. The theoretical analysis is discussed with the emphasis on the two- and three-dimensional simulation using finite difference time domain method. It is also experimentally shown that the near-field light enhancement in a waveguide of a clad covered with corrugated gold thin film was observed and that the near-field light enhancement in a waveguide without the film was not. If the corrugation pitch and the focused laser wavelength used with self-aligned microlens are designed properly, more than 20% throughput will be realized using nanometer fabricated metallic grating.