Near-field optical recording based on solid immersion lens (SIL) system has attracted much attention in the high-density storage in recent years. The recording spot size can be decreased using the SIL effectively. The SIL near-field optical storage has advantages of high density, mass storage capacity and compatibility with many technologies well developed. We have set up a SIL near-field static recording system. The experimental result with recording spot size 200 nm is presented. The influence factors in SIL near-field recording system are also discussed in the paper. Near-field optical virtual probe (NFOVP) is a kind of virtual probe by the evanescence wave interference and aperture diffraction based on SIL. It has a great potential in near-field optical data storage. In this paper, the most important characteristics of the NFOVP has been revealed through numerical simulation. The FWHM of central peak, the size of near-field virtual probe is constant whatever the distance increases in a certain range so that the critical nano-separation control in the SIL near-field data storage system can be relaxed. A realization model of NFOVP based on SIL system for data storage has been proposed and the simulation result based on this model is presented.
The aberrations are introduced by a hemisphere solid immersion lens (SIL) with a thickness error or a lateral eccentricity in the SIL optical data-storage system. Numerical computation about these aberrations is presented. We have investigated the influence of these aberrations on the focus spot size, signal intensity, and signal contrast. The simulation results show that a tolerance of the SIL is about ± 20μm in the thickness or in lateral eccentricity.
Near-field optical recording based on solid immersion lens (SIL) system has attracted great attention in the field of high-density data storage in recent years. The diffraction limited spot size in optical recording and lithography can be decreased by utilizing the SIL. The SIL near-field optical storage has advantages of high density, mass storage capacity and compatibility with many technologies well developed. We have set up a SIL near-field static recording system. The recording medium is placed on a 3-D scanning stage with the scanning range of 70×70×70μm and positioning accuracy of sub-nanometer, which will ensure the rigorous separation control in SIL system and the precision motion of the recording medium. The SIL is mounted on an inverted microscope. The focusing between long working distance objective and SIL can be monitored and observed by the CCD camera and eyes. Readout signal can be collected by a detector. Some experiments have been performed based on the SIL near-field recording system. The attempt of the near-field recording on photochromic medium has been made and the resolution improvement of the SIL has been presented. The influence factors in SIL near-field recording system are also discussed in the paper.
Near-field optical virtual probe (NFOVP) is a kind of immaterial tip based on evanescence wave interference and nano-aperture diffraction, which has great potential in near-field optical data storage, nano-lithography, near-field optical imaging and spectral detection, near-field optical manipulation and etc. . In this paper, the characteristics of NFOVP have been revealed through numerical simulation by the method of 3-D Finite-Difference Time-Domain (FDTD) and vector diffraction. The simulation results show that the transmission efficiency is higher than that of nanoaperture metal-coated fiber probe widely used in near-field optical systems. The FWHM of central peak, in other words, the size ofnear-field virtual probe is constant whatever the distance increases in a certain range so that the critical nanoseparation control in near-field optical system can be relaxed. A realization model of NFOVP in solid immersion lens system has been proposed. The influences of some factors of NFOVP, such as the shape and size of aperture, polarization and etc. have been analyzed. And the results also show that sidelobe suppression may depend on optimization ofaperture function and incident beams of NFOVP.
High density optical data storage based on near-field optical super resolution is a new t4echnique that attracts great attention in recent years. Super-resolution near-field structure, glass/SiN/Sb/SiN, a promising structure for near field ultrahigh-density optical storage, has been proposed and investigated since 1998. The recording mark size is a few tens of nanometers, far beyond the diffraction limit of the traditional optics. The mechanism of this Super-RENS including the working principle of the non-linear optical layers and the size reduction of the recording marks has not been clearly understood. In this paper, the electromagnetic propagation in Super-RENS is numerically simulated. The results show that the recording mark size is reduced and the peak intensity increased by the Super-RENS. The mechanisms of the phenomenon is discussed.
It is the chief difficulty of laser cladding metal-ceramics layer that cracks are liable to emerge. The processing technology and coating materials are studied to resolve the problem. Firstly, according to the calculating of temperature field distribution and analysis of thermal stress in the cladding procedure, it is considered that the scanning velocity of laser beam and initial temperature are the main technological factors of crack emergence. On the other hand, the gradient distribution of ceramic hard phase is carried out and transition layer is put in between cladding layer and substrate. The results of SEM and microhardness test show, the hardness changed smoothly from surface to substrate, coating layer is dense and free of cracks.