Author Affiliations
Abstract
State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China
A novel see-through virtual retina display (VRD) system is proposed in this Letter. An optical fiber projector is used as the thin-light-beam source, which is modified from a laser scan projector by separating the laser sources and the scan mechanical structure. A synthetic aperture method is proposed for simple, low-cost fabrication of a volume holographic lens with large numerical aperture. These two key performance-enhanced elements are integrated into a lightweight and ordinary-glasses-like optical see-through VRD system. The proposed VRD system achieves a weight of 30 g and a diagonal field of view of 60°.
090.2820 Heads-up displays 090.2890 Holographic optical elements 170.5755 Retina scanning 110.2350 Fiber optics imaging Chinese Optics Letters
2019, 17(9): 090901
Author Affiliations
Abstract
1 School of Electronic and Communication, Shenzhen Institute of Information Technology, Shenzhen 518172, China
2 State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications (BUPT), Beijing 100876, China
A computer generated holographic stereogram based on the wavefront recording plane (WRP) is presented. A WRP closed to the parallax image plane is introduced to record the complex amplitude in a small region for each point in the parallax image. By using three times of fast Fourier transform (FFT) to execute the Fresnel diffraction calculation between the WRP and the holographic stereogram plane, the object wave contributing to the hologram pattern can be achieved. The computation complexity of the proposed approach is dramatically reduced. The results show that the calculation time can be decreased by more than one order of magnitude.
090.1760 Computer holography Chinese Optics Letters
2017, 15(12): 120901
Author Affiliations
Abstract
1 State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China
2 School of Computer Science, National University of Defense Technology, Changsha 410073, China
Holographic head-mounted display (HHMD) is a specific application of holography. The previous conventional computer-generated hologram (CGH) generation method has a large redundancy and suffers from a heavy computing burden in the HHMD. A low redundancy and fast calculation method is presented for a CGH that is suitable for an HHMD with the effective diffraction area recording method. For the limited pupil size of an observing eye, the size of the area producing an effective wavefront is very small, and the calculated amount can be dramatically reduced. A numerical simulation and an augmented virtual reality experimental system are presented to verify the proposed method. 1.5% of the calculation consumption of the conventional CGH generation method is used, and good holographically reconstructed images can be observed.
090.0090 Holography 090.2820 Heads-up displays 090.1760 Computer holography Chinese Optics Letters
2016, 14(8): 080901
Author Affiliations
Abstract
Reconstruction the computer generated Fresnel hologram of complex 3D object based on compressive sensing (CS) is presented. The hologram is synthesized from a color image and the depth map of the 3D object. With the depth map, the intensity of the color image can be divided into multiple slices, which satisfy the condition of the sparsity of CS. Thus, the hologram can be reconstructed at different distances with corresponding scene focused using the CS method. The quality of the recovered images can be greatly improved compared with that from the back-propagation method. What’s more, with the sub-sampled hologram, the image can be ideally reconstructed by the CS method, which can reduce the data-rate for transmission or storage.
090.1760 Computer holography 090.2870 Holographic display Chinese Optics Letters
2014, 12(8): 080901
北京邮电大学信息光子学与光通信国家重点实验室, 北京 100876
提出了利用二维彩色图像和深度图生产计算菲涅耳全息图的方法。把二维彩色图像按深度图分为多层物面信息，并把每层物面深度值转换为菲涅耳衍射距离。根据层析法原理，采用单步菲涅耳衍射算法，即可得到三维场景的计算全息图。研究结果显示该方法可以正确地对复杂三维场景进行全息图的记录和再现。利用强度叠加法对再现像进行散斑去除，提高了再现三维图的质量。
全息 深度图 层析法 单步菲涅耳衍射算法 强度叠加法
华南理工大学理学院物理系， 广东 广州 510641
提出了一种双包层单模光纤传感器结构，根据波导理论推导出了光纤中导模变为泄漏模时，外包层折射率与双包层结构参量之间的关系，获得了这种光强调制型传感器可测量的折射率变化范围。利用已知热光系数的材料制作的温度传感器，从实验上证实了理论分析结果，并由理论与实验结果的分析得到了传感器的工作原理是：导模变为泄漏模后，输出光强与外包层一定范围的折射率变化有准线性关系。获得了在55~105 ℃的温度范围内的具有准线性响应的温度传感器，光强变化范围达到了39 dB；提出了利用一种围栏结构在光纤上涂覆敏感材料的简便方法，用琼脂糖制作出了插入损耗仅0.5 dB、相对湿度（RH）在30%~100%范围具有准线性响应、光强变化范围接近9 dB的光纤湿度传感器。
传感器 双包层单模光纤 波导理论 泄漏模 折射率测量范围 温度传感器 湿度传感器
