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题名	相变存储材料光学特性的超快多阶调制研究
作者	温帅
文献子类	硕士
导师	王阳
关键词	相变材料 phase-change material 皮秒激光 picosecond laser pulse 多阶编码 multi-level coding 并行调控 parallel modulation
其他题名	Ultrafast multi-level modulation of optical properties of phase-change memory materials
英文摘要	硫系相变材料由于其不同相态间明显的光学差异、良好的光热稳定性以及在激光作用下高速可逆相变的能力在可擦重写光存储中获得应用。近年来，超快激光脉冲诱导硫系相变材料的可控相变研究得到越来越多的关注，在全光存储器、可重构光子器件、灰度和彩色显示、智能运算等领域展现出广阔的应用前景。其超短的加热时间让精确控制相变薄膜的晶化程度变得可能，同时超短的操作时间极大提高了调控速率。 在本论文中，我们利用单脉冲皮秒激光在Ge2Sb2Te5薄膜上实现了多个具有不同晶化程度的中间态的建立、转换与编码操作。在具有合适能量密度的单脉冲皮秒激光调控下，5个不同的光学状态（非晶态和4个近非晶态）间可以实现相互转换，也可以在两个特定中间态间实现可逆循环。对各个过程的相变动力学作了详细的分析，结合各状态光学性质及微观结构的表征结果，对超快调控机制作了深入的讨论。 在本论文中，我们基于空间光调制器搭建了皮秒激光诱导的并行相变调控系统，通过改变输入期望图形的灰度与尺寸完成了对Ge2Sb2Te5薄膜上辐照区域晶化程度与晶化范围的调制，实现了无机械的扫描调控功能，演示了不同大小、灰度信息点的并行写入，并对选定信息点的晶化程度进行了独立的调控。 研究结果对深入理解硫系相变材料的多阶超快相变机理，设计并研发新型可重构超表面和光学器件以及构建无机械并行相变调控系统等具有重要的参考价值。; Chalcogenide phase change materials are successfully applied to rewritable optical disks because of their high optical contrasts between different phase states, sufficient photo-thermal stability and the laser-induced fast reversible phase transition ability. In recent years, controllable phase transition of chalcogenide phase change materials driven by ultrafast laser pulses are focused on for its potential applications in all-optical memory, reconfigurable photonic devices, gray-scale and colorful display, arithmetic computing and so on. The ultrashort heating time is helpful to the precise control of the crystallization degree of phase-change materials and the ultrashort operation time can enhance the adjusting speed obviously. In this thesis, the establishment, transformation and coding processes of 5 intermediate states with different crystallization degrees on Ge2Sb2Te5 thin film were accomplished by single-shot picosecond laser pulses. By applying single-shot picosecond laser pulses with suitable fluences, each of the established five states (an amorphous state and 4 near-amorphous states) can be transformed to any of the other four and the reversible switching between two specified intermediate states can also be fulfilled. The time-resolved phase transition dynamics of each process were analyzed in detail. The ultrafast adjusting mechanism was discussed with the characterization results of the optical and structural properties of the films at different states. In this thesis, an ultrafast parallel modulation system for selected-area phase transition was set up based on a picosecond laser and a spatial light modulator. The modulation of the crystallization degree and the size of the crystallized area were fulfilled by changing the gray scale and pixel number of the expected figure. The function of non-mechanical beam-scan writing was realized preliminarily. The parallel writing of spots (lines) with different sizes and gray scales was demonstrated. The crystallization degree of each spot (line) can be modulated independently. The research results will be helpful for the deep understanding of the mechanism of multi-level ultrafast phase modulation, designing and developing new reconfigurable metasurfaces and optical devices, and constructing a non-mechanical parallel modulation (direct writing) system.
学科主题	光学工程
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/31122]
专题	中国科学院上海光学精密机械研究所
作者单位	中国科学院上海光学精密机械研究所
推荐引用方式 GB/T 7714	温帅. 相变存储材料光学特性的超快多阶调制研究[D].

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