Author Affiliations
Abstract
1 Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education and Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, China
2 Shenzhen Lubon Technology Co., Ltd., Shenzhen 518000, China
More durable (with high impact force), lighter, and more compact flexible azo dye micropolarizers are attractive candidates for low-cost, simple polarization imaging systems. The liquid crystal polymer (LCP), as an emerging material developed by photo-alignment technology, is a potential material for organizing the long-range ordered structure of azo dyes. However, little research has been done on LCP aligned azo dyes. This paper points out and solves a key problem that restricts the fabrication of high-precision arrays in guest (azo dye)-host (LCP) systems: the doping of dyes leads to disorder of the LCP during curing. After solving the problem, the relationship between the thickness of the LCP and the extinction ratio of the polarizing film was investigated, which effectively improved the extinction ratio. Alignment of azo dye molecules in the range of 2 µm (0°–180°) and arrays of micropolarizers (0°, 45°, 90°, ) with 8 µm × 8 µm pixel pitch was achieved by laser direct writing technology. The bending cycle test demonstrates the mechanical stability of the ultrathin flexible polarizer. The flexible patterned polarizer with robust chemical and mechanical stabilities provides a flexible way to capture the polarization of the light and highly integrated advanced flexible optoelectronic devices.
micropolarizer polarimetric imaging polarimetry azo dye polarization-sensitive devices Chinese Optics Letters
2023, 21(3): 031301
Author Affiliations
Abstract
Department of Precision Mechanical Engineering, Shanghai University, Shanghai 200072, China
We propose a computational method for generating sequential kinoforms of real-existing full-color threedimensional (3D) objects and realizing high-quality 3D imaging. The depth map and color information are obtained using non-contact full-color 3D measurement system based on binocular vision. The obtained full-color 3D data are decomposed into multiple slices with RGB channels. Sequential kinoforms of each channel are calculated and reconstructed using a Fresnel-diffraction-based algorithm called the dynamicpseudorandom-phase tomographic computer holography (DPP-TCH). Color dispersion introduced by different wavelengths is well compensated by zero-padding operation in the red and green channels of object slices. Numerical reconstruction results show that the speckle noise and color-dispersion are well suppressed and that high-quality full-color holographic 3D imaging is feasible. The method is useful for improving the 3D image quality in holographic displays with pixelated phase-type spatial light modulators (SLMs).
计算全息 彩色全息 全息显示 序列相息图 色差矫正 090.1760 Computer holography 090.1705 Color holography 090.2870 Holographic display 100.6890 Three-dimensional image processing Chinese Optics Letters
2011, 9(4): 040901
对基于多重分数傅里叶变换(FrFT)的三维(3D)物场计算全息图进行光电再现实验研究。根据分数阶与衍射距离的关系，对不同物面分别设置不同的分数阶，分别计算得到各层物面在全息面的复振幅并进行叠加，对其进行编码分别得到分数傅里叶变换振幅型全息图和相息图。同时在计算3D物场的全息图时，在物波面加入不同的随机相位因子，得到3D物场的序列全息图，实现对再现影像中散斑噪声的抑制。构建了基于相位型液晶空间光调制器的全息光电再现系统，对单幅全息图和序列全息图的光电再现像的散斑指数、互相关系数进行分析。实验结果表明,通过计算3D物场的分数傅里叶变换序列相息图，可有效地抑制3D物场全息光电再现时的共轭像和散斑噪声，提高再现像的质量。
全息 分数傅里叶变换 计算全息图 三维成像 光电再现 激光与光电子学进展
2011, 48(2): 020901
提出了一种基于正交柱透镜光栅的计算全息三维成像方法。该方法采用CCD获取三维场景经过正交柱透镜光栅后所形成的基元图像阵列, 并采用正交投影方法对获取的基元图像阵列进行像素重组, 从而获取子图像阵列。根据透镜的傅里叶变换特性, 对每幅子图像乘以相应的倾斜因子进行积分运算得到全息面上对应点的复振幅。然后通过编码获得三维场景的傅里叶全息图。依据菲涅耳衍射理论, 在计算机中对获得的全息图进行模拟再现, 在不同再现距离上获得处于不同深度位置上的两个骰子的清晰再现, 表明该方法可实现对三维场景的计算全息成像。
计算全息 三维成像 正交柱透镜光栅 子图像阵列 基元图像阵列
提出了一种基于圆柱雾屏承载全息光电再现三维(3D)影像的方法。通过基于菲涅耳衍射原理的动态随机相位层析法(DPP-TCH)结合空间坐标变换技术计算获得3D物体360\O视角相息图，对每视角单幅相息图及每视角多幅相息图的数值再现结果进行对比分析。构建了基于液晶空间光调制器(LC-SLM)的实验系统进行全息光电再现，并采用圆柱雾屏对光电再现3D影像进行承载实验。实验结果表明，该系统可有效地实现3D物体的全息光电再现动态影像的空间承载，抑制3D再现像的散斑噪声。
计算全息 三维影像承载 圆柱雾屏 光电再现 激光与光电子学进展
2010, 47(10): 100901
Author Affiliations
Abstract
Department of Precision Mechanical Engineering, Shanghai University, Shanghai 200072, China
In order to realize holographic display of three-dimensional (3D) objects and suppress zero-order light, conjugate image, and speckle noise, a novel method is proposed based on multiple fractional Fourier transform (M-FrFT) for calculating holograms of 3D objects. A series of kinoforms are generated by adding pseudorandom phase factor (PPF) to object planes in calculating each kinoform, and generating the PPF randomly again in the next kinoform calculation. The reconstructed images from kinoform sequence are superposed together in order to suppress the speckle noise of reconstructed image and improve the contrast and detail resolution of the reconstructed images. The qualities of reconstructed images from single amplitude hologram, single kinoform, and kinoform sequence calculated by M-FrFT are compared. The effects of suppressing speckle noise are analyzed by calculating the speckle index of numerical reconstructed images. The analytical results illustrate that, with the proposed method for 3D holographic display, the zero-order light, conjugate image, and speckle noise can be suppressed, and the qualities of reconstructed images can be improved significantly.
计算全息 三维立体显示 多重分数傅里叶变换 相息图 090.1760 Computer holography 070.2575 Fractional Fourier transforms 100.6890 Three-dimensional image processing Chinese Optics Letters
2009, 7(12): 1151
