共查询到20条相似文献,搜索用时 31 毫秒
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We propose to use diffractive optical element in combination with high NA lens axicon to achieve a high depth of focus when illuminated by a circularly polarized beam. With this kind of system, the focal depth is increased to 12.816λ and the magnetic spot size is reduced to 0.3764λ. However, in the conventional lens with same NA, the FWHM of the magnetic spot is found to be 0.4308λ and its corresponding magnetization depth is only 0.888λ. The author expects that such a high focal depth strong longitudinal magnetic field with large magnetization depth can be widely used in high density magneto optic recording, laser machining, laser cutting and the scanning near-field magnetic microscope. 相似文献
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AgInSbTe薄膜的短波长记录性能分析 总被引:1,自引:0,他引:1
采用自制的装置研究了Ag5In5Sb47Te33薄膜的静态记录性能与记录激光的功率和脉冲宽度的关系,并对其记录畴形貌特点进行了直接观察。结果表明只有记录激光的功率和脉冲宽度在一定范围之内才能起到信息记录的作用,所得的记录畴形貌十分清晰,基本为非晶态Ag5In5Sb47Te33;小于该范围的激光能量不能使材料结构发生较大的变化,所得的记录畴形貌模糊,反射率对比度低于2%;大于该范围所得的记录畴由烧蚀区和其周围的非晶态Ag5In5Sb47Te33组成。另外,得到了记录激光功率为12mW、脉冲宽度为90ns的Ag5In5Sb47Te33薄膜的短波长最佳记录条件,其记录畴的反射率对比度为22%,直径为380nm-400nm。 相似文献
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LIU Huiyong JIANG Fusong MEN Liqiu FAN Zhengxiu GAN Fuxi 《Chinese Journal of Lasers》1998,7(2):158-163
HighReflectionGe0.45Te0.55RecordingFilmsLIUHuiyongJIANGFusongMENLiqiuFANZhengxiuGANFuxi(ShanghaiInstituteofOptics&FineMechani... 相似文献
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激光光束是一种振幅和等相位面都在变化的高斯球面光波,其最小光斑的位置和大小不易确定,本文在实践的基础上提出一种测量基模(TEM00)激光光斑尺寸的方法,解决了这一问题. 相似文献
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Ryuichi Katayama 《Optical Review》2014,21(5):687-693
The effect of offsets between the focused spot positions of two recording beams used in microholographic memory in the in-plane and vertical directions of the recording medium on the readout signal was investigated through a numerical simulation. The tolerance of recording beam offsets, which was defined as the offset when the normalized signal level decreased to 0.8, was determined to be 0.092 and 0.54 μm in the in-plane and vertical directions, respectively, when the wavelength of the laser was 405 nm and the numerical aperture of the objective lenses was 0.85. These values correspond to 16% of the focused spot size. Moreover, when the recording beam offsets were within the above values and the signal-to-noise ratio of 2 was allowed, the bit intervals of 0.15 and 0.75 μm in the in-plane and vertical directions, respectively, which correspond to the recording density of 59 bit/μm3, were shown to be feasible for confocal detection. 相似文献
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Akira Kikitsu 《Journal of magnetism and magnetic materials》2009,321(6):526-530
Prospects for bit patterned media (BPM) of more than 1 Tb/in2 are discussed. Improvement in the pattern drawing for small feature size and high precision is necessary for fabrication process. Deviation in the magnetic properties should be estimated and reduced. The etching damage seems not to be large. Design of the substructure of the magnetic dot is necessary for reducing the deviation. BPM is also a good template for technologies to increase the recording density. Combination of BPM with heat-assisted recording or exchange-coupled layers is advantageous for high-density recording. 相似文献
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Shun-ichi IWASAKI 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2009,85(2):37-54
The principle of conventional magnetic recording is that magnetic fields are applied parallel to the plane of the magnetic medium. As described in this paper, the invention and development of a new method of placing the magnetized information perpendicular to the plane of the magnetic recording medium is presented. The yield in the mass production of high-density hard disk drives (HDDs) for perpendicular recording is much higher than that of HDDs for conventional recording. Consequently, it is estimated that as many as 75% of the 500 million HDDs to be shipped this year will use this technology. 相似文献
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描述了一种热辅助磁盘存储技术,该技术可应用于未来的高密度磁盘存储.记录介质是一种CoNi/Pt多层膜,它可用作垂直模式的磁记录介质.使用扫描隧道显微镜(STM)产生的隧道电流作为热源对磁膜进行局部加热.隧道电流随着加在STM针尖与磁膜之间的脉冲电压幅值的增大而增大.实验结果显示了圆形记录点在磁膜上生成,记录点尺寸与电压值相关,阈值电压为4V左右.当电压高于阈值时,记录点尺寸随着电压的增大而增大,平均尺寸为170nm;当电压低于阈值时,未发现记录点.一个简单的模型解释了以上实验现象.
关键词:
扫描隧道显微镜
热辅助磁盘存储技术
高密度磁盘存储 相似文献
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Reversible,electical and optical switching on silver 3—phenyl—1—ureidonitrile complex thin films
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We report on the reversible, electrical and optical switching on silver 3-phenyl-1-ureidonitrile complex thin films. The films can switch from a high impedance state to a low impedance state with an applied electric field at the threshold of 3.5×107V/m. Furthermore, the films can be switched back to the original state by treating the samples at about 80℃. The optical recording is fulfilled using a semiconductor laser with a wavelength of 780 nm. Erasure can be accomplished by bulk heating or by the laser working with the power beneath the threshold. No loss of the organic was found in the experiments. This material may have a potential application in ultrahigh data density storage. 相似文献
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We have developed a near-field optical probe that uses a triangular metallic plate with a three-dimensionally tapered apex as a light source for thermally assisted magnetic recording. Numerical analysis using a finite-element method shows that the size of the optical spot generated at the apex is 15 nm x 20 nm, and the efficiency (defined as the ratio between the power of the optical near field at the surface of the recording medium and that of the incident light) is 15% when the incident light is focused by a lens with a numerical aperture of 0.8. The metallic plate was fabricated on the surface of a quartz slider and used for writing marks on a phase change recording medium. The marks were observed with a scanning electron microscope, and we confirmed that marks with a diameter of 40 nm were successfully written on the medium. 相似文献
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Toru Asahi Isao Koizumi Yuta Kikuchi Masahiro Yoshino Atsushi Sugiyama Jiro Hokkyo Tetsuya Osaka 《Journal of magnetism and magnetic materials》2008
An SmCo5 alloy is a promising candidate for ultra-high density magnetic recording media because of its strong uniaxial magnetocrystalline anisotropy, whose constant, Ku, is more than 1.1×108 erg/cm3. Recently, we successfully obtained high perpendicular magnetic anisotropy for a sputter-deposited SmCo5 thin film by introducing a Cu/Ti dual underlayer. However, it is necessary to improve magnetic properties and read/write (R/W) characteristics for applying SmCo5 thin films to perpendicular magnetic recording media. In this study, we focused on reduction of magnetic domain size and change of a magnetization reversal process of SmCo5 perpendicular magnetic thin films by introducing carbon (C) atoms into the constituent Cu underlayer. The magnetic domain size became small and the ratio of coercivity (Hc) against magnetic anisotropy (Hk) which is an index of the magnetization reversal process was increased by adding C atoms. We also evaluated the R/W characteristics of SmCo5 double-layered media including C atoms. The medium noise was decreased and signal-to-noise ratio increased by introducing the C. The addition of C into the Cu underlayer is effective for changing the magnetization reversal process, reducing medium noise and increasing SNR. 相似文献
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H.J. Richter 《Journal of magnetism and magnetic materials》2009,321(6):467-476
The fundamental limit of magnetic recording density on conventional media is set by the grain size. Once this grain size limit is reached, only a reduction of the grain size allows an increased SNR and thus an increased areal density. It is shown that, whilst maintaining thermal stability, scaling demands that the required anisotropy energy density K is proportional to the areal density, or the square of the areal density if the medium thickness reaches the critical thickness (A is the exchange stiffness of the material). Recording onto materials with such a high anisotropy requires some form of a write-assist. It is furthermore shown that the grain size limit cannot be obtained with intergranular exchange present, and six different requirements are listed that constitute ideal media. An alternative path for increasing areal density of magnetic recording is to use patterned media, where each bit contains only one grain. In this case, written-in errors dominate system performance and the maximum achievable areal density is estimated to be about 6 Tbit/in2. Patterned media need to exhibit narrow distributions of their physical and structural properties with standard deviations of the order of 5% or less. 相似文献
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Investigation of Near-Field Imaging Characteristics of Radial Polarization for Application to Optical Data Storage 总被引:4,自引:0,他引:4
Wan-Chin Kim No-Cheol Park Yong-Joong Yoon Hyun Choi Young-Pil Park 《Optical Review》2007,14(4):236-242
Radially polarized incident light can generate a more confined longitudinal electric field on a focal plane in near-field
(NF) optics than focusing circularly polarized light. Using this phenomenon, it is feasible to reduce beam spot size on storage
media to increase the areal density of optical data storage. A radially polarized beam generates a beam spot which is 20%
more confined on the 1st surface of medium than that of circularly polarized light. However, the peak intensity of total electric
field sharply decreases and its transverse component is much more dominant inside the media stack. This confirms that radially
polarized optics can be a candidate not for an NF recording system but for an NF read-only memory (ROM) system. Potentially,
the results could be useful to understand the effect of radial and circular polarizations inside and outside medium for various
applications of NF optics. 相似文献
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具有四方结构的L10-FePt合金因其具有高磁晶各向异性和良好的化学稳定性而成为超高密度薄膜磁记录介质的最佳选择.对实验制备得到的磁性能良好的垂直取向L10-FePt合金单层膜进行了微磁学分析.在传统微磁学模型的基础上,根据晶体的对称性,引入了四角磁晶各向异性能密度的唯象表达形式;又依据薄膜生长过程中晶格对称性的破坏,考虑了薄膜面内的应力,并引入了磁弹性能.以四角磁晶各向异性能和磁弹性能为重点,对L10-FePt合金单层膜的磁滞回线进行了详细的分析,并且用微磁学方法确定了薄膜面内应力的大小. 相似文献
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B.D. Terris 《Journal of magnetism and magnetic materials》2009,321(6):512-517
Lithographically patterned recording media are one of the approaches to achieving Tb/in2 and beyond recording densities. This will require fabrication of sub-10 nm discrete magnetic islands covering a full disk with tight spacing and size distributions and a narrow switching field distribution. To become an economically successful technology, this will need to be achieved with high throughput and low cost. The technology to fabricate such patterned media will need to be developed, and may require innovative solutions such as self-assembly and nanoimprinting, along with improved magnetic thin films for achieving high anisotropy and narrow switching field distributions. 相似文献
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运用矢量衍射理论的计算方法(耦合波方法,时域有限差分法),对两种多阶光存储方案(坑深调制,坑形调制)进行了原理性分析,并简略分析了利用相变材料的幅值调制实现多阶存储的原理.由此得出多阶光存储技术的实现是利用了光与物质之间的相互作用,使光对记录介质产生作用,同时介质也对光的某些特性进行调制,而这些特征的改变一般都不止两个状态0或1,用数字方式将这多个状态记录下来便实现了多阶数字存储.此外,还提出了多阶光盘前端信号处理系统的设计与开发.该系统是多阶光存储实验系统的重要组成部分,可输出RF,TE,FE等伺服与误差信号,并将信号反馈给多阶处理芯片;同时系统还可对光学头的激光读写功率及写入时间进行控制,并能使其实现自动调焦和道跟踪.
关键词:
多阶光存储
矢量衍射理论
时域有限差分法 相似文献