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Diffraction, Gratings, and Holography|37 Article(s)
High-quality hologram generation based on a complex-valued hierarchical multi-fusion neural network
Jiahui Fu, Wenqiang Wan, Yunrui Wang, and Yanfeng Su
In this paper, we propose a novel complex-valued hierarchical multi-fusion neural network (CHMFNet) for generating high-quality holograms. The proposed architecture builds upon a U-Net framework, incorporating a complex-valued multi-level perceptron (CMP) module that enhances complex feature representation through optimized convolutional operations and advanced activation functions, enabling effective extraction of intricate holographic patterns. The framework further integrates an innovative complex-valued hierarchical multi-fusion (CHMF) block, which implements multi-scale hierarchical processing and advanced feature fusion through its specialized design. This integration of complex-valued convolution and specialized CHMF design enables superior optical information representation, generating artifact-reduced high-fidelity holograms. The computational results demonstrate the superior performance of the proposed method, achieving an average peak signal-to-noise ratio (PSNR) of 34.11 dB and structural similarity index measure (SSIM) of 0.95, representing significant improvements over conventional approaches. Both numerical simulations and experimental validations confirm CHMFNet’s enhanced capability in hologram generation, particularly in terms of detail reproduction accuracy and overall image fidelity. In this paper, we propose a novel complex-valued hierarchical multi-fusion neural network (CHMFNet) for generating high-quality holograms. The proposed architecture builds upon a U-Net framework, incorporating a complex-valued multi-level perceptron (CMP) module that enhances complex feature representation through optimized convolutional operations and advanced activation functions, enabling effective extraction of intricate holographic patterns. The framework further integrates an innovative complex-valued hierarchical multi-fusion (CHMF) block, which implements multi-scale hierarchical processing and advanced feature fusion through its specialized design. This integration of complex-valued convolution and specialized CHMF design enables superior optical information representation, generating artifact-reduced high-fidelity holograms. The computational results demonstrate the superior performance of the proposed method, achieving an average peak signal-to-noise ratio (PSNR) of 34.11 dB and structural similarity index measure (SSIM) of 0.95, representing significant improvements over conventional approaches. Both numerical simulations and experimental validations confirm CHMFNet’s enhanced capability in hologram generation, particularly in terms of detail reproduction accuracy and overall image fidelity.
Chinese Optics Letters
- Publication Date: Aug. 21, 2025
- Vol. 23, Issue 9, 090501 (2025)
Complex amplitude and polarization modulated holographic data storage retrieved by orthogonally polarized light
Shujun Zheng, Shenghui Ke, Hongjie Liu, Xueyan Chen, Zhengyu Li, Yi Yang, Xiao Lin, and Xiaodi Tan
We propose a precise reconstruction, with crosstalk-free switching, of two holograms. Our approach utilizes orthogonal polarizations that illuminate the holograms to modulate both amplitude/phase and polarization, effectively mitigating crosstalk between the hologram data streams. Furthermore, the incorporation of a 90° interference angle facilitates the recording of multiple holograms. Experimental results have demonstrated the high-precision decoding of amplitude, phase, and polarization data for two reconstructed holograms. The integration of orthogonally polarized light with a 90° interference angle sets the stage for achieving multi-dimensional polarization modulation in systems with more than two channels. We propose a precise reconstruction, with crosstalk-free switching, of two holograms. Our approach utilizes orthogonal polarizations that illuminate the holograms to modulate both amplitude/phase and polarization, effectively mitigating crosstalk between the hologram data streams. Furthermore, the incorporation of a 90° interference angle facilitates the recording of multiple holograms. Experimental results have demonstrated the high-precision decoding of amplitude, phase, and polarization data for two reconstructed holograms. The integration of orthogonally polarized light with a 90° interference angle sets the stage for achieving multi-dimensional polarization modulation in systems with more than two channels.
Chinese Optics Letters
- Publication Date: Apr. 29, 2025
- Vol. 23, Issue 5, 050501 (2025)
Single-frame multiwavelength coherent diffraction imaging using extreme ultraviolet high-harmonic comb sources|Editors' Pick
Huixiang Lin, Jin Niu, Kui Li, Pengju Sheng, Angyi Lin, Jianfeng You, Jie Li, Xiaoshi Zhang, and Fucai Zhang
Coherent diffraction imaging (CDI) enables diffraction-limited high-resolution imaging without using high-quality lenses. It will be desirable to combine it with multiple spectral light sources to achieve chemically resolved imaging capability. Here, we demonstrate a single-frame multiwavelength CDI approach that can provide complex transmittance images of a sample at multiple wavelengths. The superior performance of our method in terms of rapid convergence and improved image quality over current methods has been validated through high-harmonic extreme ultraviolet experiments. The feasibility of our method for single-frame chemical imaging is also demonstrated by the simulation. This work can pave the way for implementing in situ chemical imaging with tabletop high-harmonic generation extreme ultraviolet sources. Coherent diffraction imaging (CDI) enables diffraction-limited high-resolution imaging without using high-quality lenses. It will be desirable to combine it with multiple spectral light sources to achieve chemically resolved imaging capability. Here, we demonstrate a single-frame multiwavelength CDI approach that can provide complex transmittance images of a sample at multiple wavelengths. The superior performance of our method in terms of rapid convergence and improved image quality over current methods has been validated through high-harmonic extreme ultraviolet experiments. The feasibility of our method for single-frame chemical imaging is also demonstrated by the simulation. This work can pave the way for implementing in situ chemical imaging with tabletop high-harmonic generation extreme ultraviolet sources.
Chinese Optics Letters
- Publication Date: Apr. 10, 2025
- Vol. 23, Issue 4, 040502 (2025)
Phong shading approximation of computer-generated holography based on fully analytical triangle meshes
Xi Zou, Qingyang Fu, Yan Liu, Min Yang, Pin Wang, Yaping Zhang, and Ting-Chung Poon
We propose a Phong shading approximation, which gives the amplitude of each point inside the triangle through linear interpolation within the framework of self-similarity segmentation and affine transformation in polygon-based computer-generated holography. Shading is important as it reflects the geometric properties of the objects. To accurately represent the geometric properties of objects in three-dimensional space, the method involves calculating the amplitude distribution on each triangle and maintaining a complete analytical framework, with the edges of the reconstructed polygons nearly unobservable. Numerical simulations and optical reconstructions demonstrate that the proposed method successfully addresses the issue of edge discontinuity on polygonal surfaces. We propose a Phong shading approximation, which gives the amplitude of each point inside the triangle through linear interpolation within the framework of self-similarity segmentation and affine transformation in polygon-based computer-generated holography. Shading is important as it reflects the geometric properties of the objects. To accurately represent the geometric properties of objects in three-dimensional space, the method involves calculating the amplitude distribution on each triangle and maintaining a complete analytical framework, with the edges of the reconstructed polygons nearly unobservable. Numerical simulations and optical reconstructions demonstrate that the proposed method successfully addresses the issue of edge discontinuity on polygonal surfaces.
Chinese Optics Letters
- Publication Date: Apr. 16, 2025
- Vol. 23, Issue 4, 040501 (2025)
Microsphere-assisted single-shot polarization holographic microscopy for quantitative birefringence imaging of dynamic samples
Qingyang Yue, Hao Ma, Yabo Han, Hongyi Huang, Xianlong Liu, Yang Yang, and Chengshan Guo
We propose a method for realizing single-shot high-resolved quantitative birefringence microscopy by extending microsphere-assisted microscopy into polarization holographic microscopy. Based on our proposed imaging system and reconstruction algorithm, we are capable of simultaneously realizing high-resolved polarization holographic imaging and quantitative measurement of 2D birefringence information of dynamic samples. We demonstrated our proposed method by quantitatively imaging a birefringence resolution target, whose resolution (0.71 µm) exceeds the resolution limit of a microscope objective with a numerical aperture of 0.25. Experimental results of rotating holographic diffraction grating with 500 lp/mm further demonstrated the feasibility of our method in birefringence imaging of dynamic samples. We propose a method for realizing single-shot high-resolved quantitative birefringence microscopy by extending microsphere-assisted microscopy into polarization holographic microscopy. Based on our proposed imaging system and reconstruction algorithm, we are capable of simultaneously realizing high-resolved polarization holographic imaging and quantitative measurement of 2D birefringence information of dynamic samples. We demonstrated our proposed method by quantitatively imaging a birefringence resolution target, whose resolution (0.71 µm) exceeds the resolution limit of a microscope objective with a numerical aperture of 0.25. Experimental results of rotating holographic diffraction grating with 500 lp/mm further demonstrated the feasibility of our method in birefringence imaging of dynamic samples.
Chinese Optics Letters
- Publication Date: Mar. 13, 2025
- Vol. 23, Issue 3, 030501 (2025)
Complex-valued dense atrous neural network for high-quality computer-generated holography
Yunrui Wang, Wenqiang Wan, Jiahui Fu, and Yanfeng Su
In this paper, we propose, to our knowledge, a new complex-valued dense atrous neural network (CDANN) for phase-only hologram (POH) generation. The network architecture integrates a complex-valued partial convolution (C-PConv) module into the down-sampling stages of dual U-Net structures, enhancing computational efficiency through selective channel-wise processing. To improve feature extraction, we introduce a novel complex-value dense atrous convolution (DAC) module, which employs four cascaded branches with multi-scale atrous convolutions to capture intricate features while maintaining spatial resolution. Additionally, we integrate a spatial pyramid pooling (SPP) module into the U-Net architecture to encode multi-scale contextual features derived from the DAC module. This hierarchical integration expands the U-Net’s receptive field while facilitating cross-layer feature fusion. The proposed method achieves an average peak signal-to-noise ratio (PSNR) of 32.19 dB and an average structural similarity index measure (SSIM) of 0.892 within a running time of 24 ms, outperforming conventional approaches. Experiments confirm significant improvements in both reconstruction quality and computational efficiency, making the CDANN suitable for real-time holographic displays. In this paper, we propose, to our knowledge, a new complex-valued dense atrous neural network (CDANN) for phase-only hologram (POH) generation. The network architecture integrates a complex-valued partial convolution (C-PConv) module into the down-sampling stages of dual U-Net structures, enhancing computational efficiency through selective channel-wise processing. To improve feature extraction, we introduce a novel complex-value dense atrous convolution (DAC) module, which employs four cascaded branches with multi-scale atrous convolutions to capture intricate features while maintaining spatial resolution. Additionally, we integrate a spatial pyramid pooling (SPP) module into the U-Net architecture to encode multi-scale contextual features derived from the DAC module. This hierarchical integration expands the U-Net’s receptive field while facilitating cross-layer feature fusion. The proposed method achieves an average peak signal-to-noise ratio (PSNR) of 32.19 dB and an average structural similarity index measure (SSIM) of 0.892 within a running time of 24 ms, outperforming conventional approaches. Experiments confirm significant improvements in both reconstruction quality and computational efficiency, making the CDANN suitable for real-time holographic displays.
Chinese Optics Letters
- Publication Date: Nov. 06, 2025
- Vol. 23, Issue 12, 120501 (2025)
Optimized binary computer holography via convolutional neural network-based differentiable binarization
Jiadi Shi, Shuqing Cao, Xian Ding, Bo Dai, Qi Wang, Songlin Zhuang, Dawei Zhang, and Chenliang Chang
Digital micromirror devices (DMDs) have emerged as essential spatial light modulators for holographic 3D near-eye displays due to their rapid refresh rates and precise wavefront modulation characteristics. However, since the modulation depth of DMDs is limited to binary levels, the quality of reproduced images from a binary computer-generated hologram (CGH) is often deficient. In this paper, we propose a stochastic gradient descent (SGD) based binary CGH optimization framework where a convolutional neural network (CNN) is employed to perform the differentiable hologram binarization operation. The CNN-based binary SGD optimization can significantly minimize the binary quantization noise in the generation of binary CGH, providing a superior and high-fidelity holographic display. Our proposed method is experimentally verified by displaying both high-quality 2D and true 3D images from optimized binary CGHs. Digital micromirror devices (DMDs) have emerged as essential spatial light modulators for holographic 3D near-eye displays due to their rapid refresh rates and precise wavefront modulation characteristics. However, since the modulation depth of DMDs is limited to binary levels, the quality of reproduced images from a binary computer-generated hologram (CGH) is often deficient. In this paper, we propose a stochastic gradient descent (SGD) based binary CGH optimization framework where a convolutional neural network (CNN) is employed to perform the differentiable hologram binarization operation. The CNN-based binary SGD optimization can significantly minimize the binary quantization noise in the generation of binary CGH, providing a superior and high-fidelity holographic display. Our proposed method is experimentally verified by displaying both high-quality 2D and true 3D images from optimized binary CGHs.
Chinese Optics Letters
- Publication Date: Sep. 16, 2025
- Vol. 23, Issue 10, 100501 (2025)
Angular-adaptive spin-locked retroreflectors based on reconfigurable origami two-dimensional metagrating
Zhibiao Zhu, Yongfeng Li, Zhe Qin, Lixin Jiang, Wenjie Wang, Hongya Chen, Jiafu Wang, Lin Zheng, and Shaobo Qu
The retroreflector based on a gradient metasurface can reflect electromagnetic (EM) waves to the source, and it is small in size and lightweight. However, even if the previous retroreflectors can be used for angle adaptation, the working efficiency declines sharply at large angles. In this paper, a retroreflector is designed based on a reconfigurable origami two-dimensional (2D) metagrating for efficient spin-locked retroreflection and for suppressing unwanted Floquet diffraction channels. After the retroreflection, the handedness of the wave remains consistent with the incident. By changing the folding state of the origami metagrating, the adaptive tangential momentum can be transferred to the incident wave, providing high-performance retroreflection over a continuous incidence angle range of 30°–45.8° (x-direction) and 30°–81° (y-direction). As proof of concept, an electric metagrating-based retroreflector is fabricated in the microwave frequency band, and the simulation and experimental results are consistent. This adaptive origami spin-locked metasurface has promising applications in spin-optics devices, communication systems, remote sensing, and radar cross-section (RCS) enhancement. The retroreflector based on a gradient metasurface can reflect electromagnetic (EM) waves to the source, and it is small in size and lightweight. However, even if the previous retroreflectors can be used for angle adaptation, the working efficiency declines sharply at large angles. In this paper, a retroreflector is designed based on a reconfigurable origami two-dimensional (2D) metagrating for efficient spin-locked retroreflection and for suppressing unwanted Floquet diffraction channels. After the retroreflection, the handedness of the wave remains consistent with the incident. By changing the folding state of the origami metagrating, the adaptive tangential momentum can be transferred to the incident wave, providing high-performance retroreflection over a continuous incidence angle range of 30°–45.8° (x-direction) and 30°–81° (y-direction). As proof of concept, an electric metagrating-based retroreflector is fabricated in the microwave frequency band, and the simulation and experimental results are consistent. This adaptive origami spin-locked metasurface has promising applications in spin-optics devices, communication systems, remote sensing, and radar cross-section (RCS) enhancement.
Chinese Optics Letters
- Publication Date: Feb. 14, 2025
- Vol. 23, Issue 1, 010501 (2025)
Optical secret sharing by multi-step liquid crystal planar doublet panning and coupling
Zhichang Mo, Yi Chen, Xiangyu Zhu, Zhouhao Zhang, Dawei Li, Jianda Shao, Yuanan Zhao, and Jianguo Wang
The hologram, which is formed by phases coupled through cascade devices for secret information sharing, still carries a cracking risk. We propose a liquid crystal planar doublet as the information carrier, and new holograms generated by the new coupled phases when the relative displacements of the different liquid crystal layers change. The designed geometrical phases are generated by an optimized iterative restoration algorithm, and each holographic image formed by these phases is readable. This scheme achieves an increase in the capacity of the stored secret information and provides more misdirection, which is expected to have potential value in optical steganography and storage. The hologram, which is formed by phases coupled through cascade devices for secret information sharing, still carries a cracking risk. We propose a liquid crystal planar doublet as the information carrier, and new holograms generated by the new coupled phases when the relative displacements of the different liquid crystal layers change. The designed geometrical phases are generated by an optimized iterative restoration algorithm, and each holographic image formed by these phases is readable. This scheme achieves an increase in the capacity of the stored secret information and provides more misdirection, which is expected to have potential value in optical steganography and storage.
Chinese Optics Letters
- Publication Date: Aug. 23, 2024
- Vol. 22, Issue 8, 080502 (2024)
Autofocus by Lissajous scanning in time reversal optical scanning holography
Jie Liu, Haiyan Ou, Hua Wang, Lin Peng, and Wei Shao
In this Letter, an autofocusing method in optical scanning holography (OSH) system is proposed. By introducing Lissajous scanning into multiple signal classification (MUSIC) method in time-reversal (TR) OSH, the axial locations of the targets can be retrieved with better resolution and the peak prominence increases from 0.21 to 0.34. The feasibility of this method is confirmed by simulation as well as experiment. In this Letter, an autofocusing method in optical scanning holography (OSH) system is proposed. By introducing Lissajous scanning into multiple signal classification (MUSIC) method in time-reversal (TR) OSH, the axial locations of the targets can be retrieved with better resolution and the peak prominence increases from 0.21 to 0.34. The feasibility of this method is confirmed by simulation as well as experiment.
Chinese Optics Letters
- Publication Date: Aug. 19, 2024
- Vol. 22, Issue 8, 080501 (2024)
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