基于相位恢复和紧聚焦光场整形的衍射光学元件设计
文献类型：学位论文
| 作者 | 查一昆 |
| 学位类别 | 博士 |
| 答辩日期 | 2013 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 干福熹 院士 魏劲松 研究员 |
| 关键词 | 相位恢复，矢量衍射，超分辨相位板，无衍射光束 |
| 其他题名 | The DOE design based on phase retrieval algorithm and tight focusing beam reshaping |
| 中文摘要 | 随着信息技术的高速发展，在光存储、光刻、光学成像等领域都需要实现纳米尺度的光斑，并且在一定条件下要特定的光强分布才能满足应用要求。传统缩小入射光波长和增大数值孔径的方法会导致焦深急剧减小，这对高速光存储和光刻领域的伺服跟踪系统提出了更高的要求。另外，在大范围的重复图形光刻方面，逐点光刻不仅速度慢而且很难保证电机运动过程中的直线度和均匀性。针对光刻和光存储等领域遇到的困难，本文的研究内容包括以下几个方面： 1． 根据需要得到的图像实现了相应的图像相位恢复算法，该算法首先由并行误差减少算法PGS (Parallel Gerchberg-Saxton)得到一个初始的相位，然后代入并行模拟退火算法PSA (Parallel Simulated Annealing)进行退火计算，最终得到一个较好的全局优化相位。PGS算法和PSA算法相结合可以计算1024×1024的大像素图像，与串行算法相比缩短了计算时间。通过空间光调制器加载计算得到的相位可以得到期望的图形。 2． 运用矢量衍射理论设计得到了在入射光为径向偏振贝塞尔分布和圆偏振均匀分布时，通过五环结构的中心遮挡的三元光学元件，得到在高数值孔径聚焦下焦平面附近的超分辨长焦深光束。该优化过程分为两步。第一，该五环结构相位板的设计方法是以限制轴向光强的均匀度和横向光斑的半高宽Full Width at Half Maximum (FWHM)为搜索条件，这两种限制条件相结合使算法具有快速的搜索速度，比传统的以限制FWHM和Depth of Focus (DOF)相结合的全局搜索算法相比更快；第二，根据FWHM的大小按照由小到大排序，为了使轴向光强更加均匀，把归一化半径的小数点位数由2为扩展到4位，从而找到效果非常好的一组归一化半径值。这种搜索方法的最大特点是节约时间。 3． 将设计得到的超分辨衍射光学元件与非线性材料相结合，进一步提高超分辨相位板的性能和实现超分辨刻录点。首先，将三环结构相位板与非线性饱和吸收材料结合进一步压缩超分辨光斑的主瓣且降低旁瓣；其次，四环结构相位板和相变材料结合，利用相变材料的阈值效应进一步减小刻录点尺寸；最后，五环结构相位板与具有非线性反饱和吸收特性的无机光刻胶结合，利用材料的能量吸收斑效应减小刻录点尺寸。 本文的内容主要侧重于理论计算方面，要更加准确的判断理论计算的可靠性，需要实际制作出相位板结合材料进行实验，这是今后要做的工作。 |
| 英文摘要 | With the development of information technology, such as optical data storage, lithography, and optical imaging and so on, the optical spot size is required to be as small as nanoscale, or the spot needs to become specific shape. The traditional way to reduce the focal spot by reducing the wavelength and increasing the numerical aperture of lens causes the DOF (depth of focus) to reduce sharply. However, the long DOF is a requirement for the tracking servo system in high speed optical data storage and nanolithography. Besides, in the area of large scale pattern lithography, for the traditional direct laser writing, there are both low speed and difficulties in controlling the linearity and uniformity of motor motion. Therefore, in this dissertation the work is as follows: 1. Phase retrieval algorithms are used to retrieve the phase of an expected grayscale image. First, we use PGS (Parallel Gerchberg-Saxton) algorithm to get the phase of the expected image; second, we put the phase obtained by the PGS algorithm into the PSA (Parallel Simulated Annealing), and the phase is used as an initial phase to get the global optimum phase. The combination of PGS and PSA can compute large pixel image, such as 1024×1024, and reduce the time cost compared with the serial algorithm. Third, we load the phase to the liquid crystal spatial light modulator (LC-SLM) to get the expected image. 2. Vector diffraction theory is used to design the ternary optical element: five-ring phase plate. By using the ternary optical element and lens with high numerical aperture, we modulate the incident radially polarized Bessel-Gaussian beam and circularly polarized uniform beam into a sub-wavelength and long DOF beam in the region of focal plane. The optimization design process is divided into two steps. One is the combination of uniformity of the beam along the z-axis in the focal region and the FWHM size of the focal spot, which allows a fast searching speed. The algorithm is much faster than the traditional exhaustive searching algorithm based on FWHM and DOF searching criteria. The other is that the FWHM is sorted from small to large，in order to obtain an ultra-long and uniform sub wavelength light beam, the two decimal digits of the tolerance are extended to four decimal digits manually according to experience, and we finally find some optimum normalized radii. The feature of our optimization method is time-saving. 3. We combine the super-resolution phase plate with nonlinear material to further improve the performance of the phase plate and obtain super-resolution lithographic mark. Firstly, a three-zone annular binary phase plate is combined with saturable absorption material to further reduce the focal spot size and suppress the side-lobe effect. Secondly, a four-zone annular binary phase plate is combined with phase change material to reduce the recording mark size according to the threshold effect of the phase change material. Thirdly, we combine a five-zone annular binary phase plate with nonlinear reverse saturable absorption inorganic resists to reduce the recording mark according to the energy absorption and threshold effect. The dissertation mainly pay attention to theoretical calculation, in order to verify the reliability of the theoretical calculation, we need to manufacture the phase plate and combine with nonlinear material in experiment, this is the work need to be done in the future. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15729]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 查一昆. 基于相位恢复和紧聚焦光场整形的衍射光学元件设计[D]. 中国科学院上海光学精密机械研究所. 2013. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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