In this paper, theoretical work on the transmitted-aperture (TA) type super-RENS was introduced. Firstly, the forming of transmitted-aperture in the mask layer was studied based on laser-induced thermal model with Gauss assumption. A numerical simulation was carried out by FEMLAB. The simulation results showed that transmitted aperture would not be formed until the exposure power exceeded a threshold within a certain pulse time and vice versa. Secondly, a calculation model of electromagnetic field of TA type super-RENS disk was presented based on the three-dimensional finite-difference time-domain method (3D-FDTD) together with a vector method of Gaussian beam. Lorenz dispersive model was employed for mask layer and reflective layer. The distributions of electric field for TA type super-RENS were theoretically analyzed. Lastly, the static writing experiment for TA type Super-RENS was carried out with different power and pulse time, as well as for conventional CD-R/W. The experiment results well satisfied the simulation.
Two stage positioning method which is composed of coarse positioning and fine positioning is a way to increase the precision of linear feeding in high density disk mastering. The control method of two stage positioning is proposed in this paper. Different control models are compared and the suitable one is chosen. The PID controllers for coarse and fine tables are designed. The numerical simulating results show that the two stage positioning system with PID controllers has good performance in linear feeding with steady error less than 10nm. The coarse positioning table compensates the major component of displacement in linear feeding while the fine positioning table compensates the minor one. The two stage positioning system can well satisfied the requirement of high density disk mastering in theoretical.
The non-linearity of the super-RENS mask can be used in optical data storage, which can greatly increase the disk’s density. Experiment is carried on the traditional mastering system with modification. We adopt the SiN/Sb/SiN multiplayer as the mask to insert the optical mask. For 413nm semiconductor laser and lens with NA=0.9, the diffraction limit is 200nm theoretically. Mark-120nm much smaller than that size is generated in the experiment. The thickness of Sb in the mask layers has much effect on the mastering signal intensity. For different power, we should control the thickness of Sb film. The experiments results show that the super-RENS mask can actually reduce the size of the mark obviously and realize the high density optical storage.