The Study Of Key Technologies In Optical Disc Data Storage With Ultrahigh Density

Optical data storage technologies are playing a more and more important role in. modern information society, but the traditional optical disc storage technology is facing the challenge not only from the rapid development of other data storage technology, but also from the demands of new optical disk storage products with higher storage density and capacity. For this reason, the ultrahigh density optical disk data storage technologies based on the solid immersion lens technology and the Sb film super resolution technology, which appear more promising to industrialize in the short term, have been studied in this paper. The aim of this paper is to develop the key technologies for next generation optical disc data storage system.First, an optical pick-up and recording head is built up by modifying the pick-up head of commercial DVD-ROM driver. Benefited from the special design, the new pick-up and recording head can use external laser source of short wavelength as well as the internal LD source of specifically wavelength to perform the write/read function on recording medium. The advantage of using external laser source is that the new pick-up and recording head can carry out the optical data storage experiment with short wavelength laser. Equipped with a specially designed digital control system, the new pick-up and recording head can perform the basic functions of optical data storage, and is used for further experiment with SIL and Sb super-RENS technology.With modified optical pick-up and recording head, a study is made on SIL data storage technology. A new remelting process is proposed to overcome the difficulty of manufacturing ball lens with the radius smaller than 0.5mm. A SIL flying head is designed to keep the distance between SIL and recording medium in near-field range. A SIL optical data storage system is built up when the recording head is combined with SIL flying head. Meanwhile, using astigmatic focusing error detection technology and twin optical pick-up heads, a novel nontouching nanometer measurement method is developed to measure the flying height of SIL, and provides us with a powerful tool to optimize the design of SIL fly head. The static recording by SIL system is performed on phase-change medium, and the recorded line width is thinner by the factor of 1.44 than the recording width without SIL system.The properties of Sb layer super resolution near-field structure is also studied.The SiN/Sb/SiN film structure is deposited on substrate of K9 glass by RF sputtering technology. By applying a pump-probe method, the variation of transmissivity of Sb layer super resolution structure is observed. The variation reveals that the Sb layer we sputtered does have the super resolution effect. The nonlinear optical properties of Sb layer are also investigated by Z-scan method. The third-order optical nonlinearity at 650 nm laser yields the value n2~10~9m2/W. The super resolution effect of Sb layer super resolution structure is also investigated with near-field scanning optical microscope.In addition, a rigorous three-dimensional (3D) optical electromagnetic finite-difference time-domain (FDTD) model for analysis of a SIL system is detailed. In order to accurately analyse SIL model, a new method of setting a focused Gaussian beam source in FDTD grids is presented. The field distribution and propagation properties in SIL system is analysed, and the relationship between the focusing spot size and the defocusing amount is also described. Moreover, a novel model is proposed on basis of the FDTD analysis that can make us increase the distance between SIL and recording medium without decreasing the recording density.