Study Of Key Issues In Super-resolution Near-field Structure Optical Storage

The traditional optical disc with limited storage density and low speed is faced with challenge due to the development of communication technology and huge demand from the market. The Super-RENS technology is able to break through the diffraction limitation and realize super high density storage, which is regarded as the closest practical approach for the next generation optical disc. So far, the researches are concentrated in mechanism studying, super-resolution mask material and disc structure optimization. For the purpose of consummating theoretical research and developing the related technologies on Super-RENS optical storage, the research in the thesis is mainly focused on improving its storage density, storage speed and the quality of readout signal.First of all, for further improving the density of Super-RENS disc, the imaging modle is established, and the distribution of electric field inside the Super-RENS disc is studied by vector imaging theory. By theoretical analysis and numerical simulation, the influence of incident laser, especially its polarized state, on the size of recording spot is investigated. The simulation results indicated that, the circularly polarized incident laser is the best choice. Moreover, the application of space filter and solid immersion lens(SIL) in Super-RENS disc system are studied. The further analyses reveal that, SIL and space filter are effective to reduce recording spot. When the numerical aperture(NA) of optical storage system or the aperture of amplitude filter is large enough, the radially polarized incident laser improves storage density remarkably.Secondly, in order to study the character of readout signal, the calculation model for the readout signal of Super-RENS disc is established, by using scalar diffraction theory and angular spectrum method, the differential readout optical method and the corresponding readout system scheme is proposed. According to theoretical analysis and numerical simulation, the influence of the incident laser and the super-resolution layer on traditional readout signal and differential readout signal are both discussed, the crosstalk are also compared for the two readout signals. Simulations results indicated that, super-resolution layer with large transmissivity parameters and differential readout method are beneficial to obtaining high quality readout signal, which is helpful for gaining higher density. The results are helpful for further improving the storage density of Super-RENS disc.In addition, the method of using parallel optical interconnection interface for data transfer, data exchange and operation is proposed, which can realize the multi-channels parallel read and write for Super-RENS disc, and resolve the difficulty of low storage speed for huge capacity optical storage system. Theoretic and experimental investigations are performed for two kinds of channel interface, which are based on 4-f structure and vector-matrix multiplication structure. The analysis results indicated that both structures are capable served as the core of multi-channels parallel interface. The analyses results of the first kind of interfaces indicate that, the misalignment of transmitter lens affects its performance much more remarkable than that of receiver lens. Moreover, the experimental studies of the second interface show that, functions such as random signal transfer, data exchange, data copy and signal reconstructable can be realized if using the interface in optical storage system. The research of new multi-channels parallel interfaces base on optical interconnection structures provides a useful approach of improving storage speed for optical mass storage system.The research is beneficial to promoting the application of Super-RENS technology and the development of mass information storage.