Near-Field Optical Storage Technology

Higher density optical disks with higher data rate and technological capability of super parallel optical heads using VCSEL (vertical cavity surface emitting laser) array are described. Optical heads using the VCSEL array and microlens array to get higher evanescent light from narrow apertures play a key role in supporting optical disks, which are coated with lubricant and protective film on their flat surfaces in order to keep the gap between the super parallel optical head and the disk surface within several 10 nano meter. Higher throughput efficiency in the near-field semiconductor optical probe array has been obtained in our optical head. However, the obtained evanescent light power is 10 μW from the 100 nm probe aperture, which is one tenth of the power needed to write a bit on the phase change optical disk surface. One solution to get ten times the power is to develop special nano fabricated optical probes of higher throughput efficiency. A metal fine grating fabrication method to get evanescent light wave resonant enhancement is planned after good 2D-FDTD simulation results.