Author Affiliations
Abstract
1 Joint International Research Laboratory of Information Display and Visualization, School of Electronic Science and Engineering, Southeast University, Nanjing 210096, China
2 Key Laboratory for Opto-Electronic Technology of Jiangsu Province, Nanjing Normal University, Nanjing 210023, China
A method is proposed to realize accurate spatial complex modulation based on the spatial cross-modulation method (SCMM) via a phase-only spatial light modulator. The conventional SCMM cannot achieve high quality reconstruction, especially when the diffusion ratio is small. We propose an iterative algorithm in the calculation of a computer-generated hologram to implement accurate complex modulation. It enables us to generate a high quality reconstruction under a small diffusion ratio. The feasibility of the method is verified by both a numerical simulation and an optical experiment.
090.2870 Holographic display 090.1760 Computer holography 110.7348 Wavefront encoding Chinese Optics Letters
2017, 15(2): 020901
Author Affiliations
Abstract
1 National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China
2 Beijing Institute of Space Mechanics and Electricity, Beijing 100076, China
3 Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
Metasurface is a new kind of 2D metamaterial that is able to manage a variety of light beam modulations through steering the phase of the scattering waves. In this work, we utilize the metasurface to manipulate the light beam in the mid-infrared regime. By using the metallic rod and the plate structure, the metasurface presents a high polarization conversion efficiency and a wide working bandwidth. With specially rotated metallic rods, the metasurface can realize various light beam manipulations, such as negative reflection, beam collimation, and focusing. All of these results show that such a metasurface will have potential applications in future mid-infrared optics.
110.7348 Wavefront encoding 130.3060 Infrared 160.3918 Metamaterials Chinese Optics Letters
2016, 14(5): 051101
清华大学精密仪器系, 精密测试技术及仪器国家重点实验室, 北京 100084
全息三维显示具有呈现包含真实物体所有特征的三维场景的能力，这对信息的数据量和分辨率提出了极高的要求。体全息术可以为高分辨率三维显示提供大容量数据存储和基于三维布拉格光栅的实现方式。提出体全息三维显示方法，通过计算全息算法得到三维物体的全视差相息图，由相位型空间光调制器对物光波进行波前编码，利用体全息光栅的角度选择特性在光致聚合物的同一全息图基元中复用多幅全息图。在参考光照射下，可以重建出多角度的三维场景，扩充了三维显示的空间带宽积。
全息 全息显示 波前编码 计算全息 体光栅 光存储材料
Author Affiliations
Abstract
1 State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China
2 College of Science, Beijing University of Posts and Telecommunications, Beijing 100876, China
We study the decoding performance of low-density parity-check (LDPC) code based on Watermark scheme under different percentages of water-mark bits over 100 Gb/s differential quadrature phase shift keying (DQPSK) high-speed optical communication system. We also find the optimum percentage of water-mark bits according to the performance comparison. Simulation result shows an improvement of 0.5 dB net code gain by using the optimum Watermark scheme at a post-forward error correction bit error rate (BER) of 10-9, comparing with the traditional log-likelihood ratios belief propagation decoding algorithm. Also, for the same BER, there is a decrease in the number of iterations used in LDPC decoding.
060.4510 Optical communications 110.7348 Wavefront encoding 150.1135 Algorithms Chinese Optics Letters
2015, 13(s1): S10601
Author Affiliations
Abstract
The wavefront coding technique is used to enlarge the depth of field (DOF) of incoherent imaging systems.The key to wavefront coding lies in the design of suitable phase masks. To date, numerous kinds of phase masks are proposed. However, further understanding is needed regarding phase mask with its phase function being in a standard sinusoidal form. Therefore, the characteristics of such a phase mask are studied in this letter. Deriving the defocused optical transfer function (OTF) analytically proves that the standard sinusoidal phase mask is effective in extending the DOF, and actual experiments confirm the numerical results. At the same time, with the Fisher information as a criterion, the standard sinusoidal phase mask shows a higher tolerance to focus errors (especially severe focus errors) than the classical cubic phase mask.
110.7348 Wavefront encoding 110.1758 Computational imaging Chinese Optics Letters
2012, 10(3): 031101
