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Diffraction, Gratings, and Holography|33 Article(s)
Single-frame multiwavelength coherent diffraction imaging using extreme ultraviolet high-harmonic comb sources
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)
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)
Bi-layered coded metasurface for multi-functional hologram with broadband transmission and efficient reflection
Lei Zhu, Xusheng Li, Liang Dong, Wenjing Xie, Guanyu Shang, Shah Nawaz Burokur, and Xumin Ding
A multi-functional full-space metasurface based on frequency and polarization multiplexing is proposed. The metasurface unit consists of metallic patterns printed on the two faces of a single-layered dielectric substrate. The unit cell can control electromagnetic wavefronts to achieve a broadband transmission with amplitudes greater than 0.4 from 4.4 to 10.4 GHz. Meanwhile, at 11.7 GHz and 15.4 GHz, four high-efficiency reflection channels with a reflection amplitude greater than 0.8 are also realized. When illuminated by linearly polarized waves, five different functions can be realized at five different frequencies, which are demonstrated by theoretical calculations, full-wave simulations, and experimental measurements. A multi-functional full-space metasurface based on frequency and polarization multiplexing is proposed. The metasurface unit consists of metallic patterns printed on the two faces of a single-layered dielectric substrate. The unit cell can control electromagnetic wavefronts to achieve a broadband transmission with amplitudes greater than 0.4 from 4.4 to 10.4 GHz. Meanwhile, at 11.7 GHz and 15.4 GHz, four high-efficiency reflection channels with a reflection amplitude greater than 0.8 are also realized. When illuminated by linearly polarized waves, five different functions can be realized at five different frequencies, which are demonstrated by theoretical calculations, full-wave simulations, and experimental measurements.
Chinese Optics Letters
- Publication Date: May. 17, 2024
- Vol. 22, Issue 5, 050502 (2024)
Linear mathematical model for the unique solution of 3D ptychographic iterative engine
Liqing Wu, Naijie Qi, Chengcheng Chang, Hua Tao, Xiaoliang He, Cheng Liu, and Jianqiang Zhu
Diffraction intensities of the 3D ptychographic iterative engine (3PIE) were written as a set of linear equations of the self-correlations of Fourier components of all sample slices, and an effective computing method was developed to solve these linear equations for the transmission functions of all sample slices analytically. With both theoretical analysis and numerical simulations, this study revealed the underlying physics and mathematics of 3PIE and demonstrated for the first time, to our knowledge, that 3PIE can generate mathematically unique reconstruction even with noisy data. Diffraction intensities of the 3D ptychographic iterative engine (3PIE) were written as a set of linear equations of the self-correlations of Fourier components of all sample slices, and an effective computing method was developed to solve these linear equations for the transmission functions of all sample slices analytically. With both theoretical analysis and numerical simulations, this study revealed the underlying physics and mathematics of 3PIE and demonstrated for the first time, to our knowledge, that 3PIE can generate mathematically unique reconstruction even with noisy data.
Chinese Optics Letters
- Publication Date: May. 17, 2024
- Vol. 22, Issue 5, 050501 (2024)
Experimental implementation of phase triplicator gratings in a spatial light modulator
Shang Gao, María del Mar Sánchez-López, and Ignacio Moreno
In this work, we compare different methods for implementing a triplicator, a phase grating that generates three equi-intense diffraction orders. The design with optimal efficiency features a continuous phase profile, which cannot be easily reproduced, and is typically affected by quantization. We compare its performance with binary and sinusoidal phase profiles. We also analyze the effect of quantizing the phase levels. Finally, a random approach is adopted to eliminate the additional harmonic orders. In all cases, a liquid-crystal-on-silicon spatial light modulator is employed to experimentally verify and compare the different approaches. In this work, we compare different methods for implementing a triplicator, a phase grating that generates three equi-intense diffraction orders. The design with optimal efficiency features a continuous phase profile, which cannot be easily reproduced, and is typically affected by quantization. We compare its performance with binary and sinusoidal phase profiles. We also analyze the effect of quantizing the phase levels. Finally, a random approach is adopted to eliminate the additional harmonic orders. In all cases, a liquid-crystal-on-silicon spatial light modulator is employed to experimentally verify and compare the different approaches.
Chinese Optics Letters
- Publication Date: Feb. 21, 2024
- Vol. 22, Issue 2, 020501 (2024)
Visualized quantum 3D orbital-angular-momentum holography
Yilin Hua, Yaodong Chen, Weijia Meng, Ke Cheng, Haitao Luan, Min Gu, and Xinyuan Fang
Currently, most quantum holography schemes adopt reconstructing images from the second-order correlation information or fiber scanning, which are both non-visualized, meanwhile making three-dimensional (3D) quantum holography a big challenge. Here, we implement the visualized quantum 3D orbital-angular-momentum (OAM) holography in the twin photon system, where the OAM-multiplexing hologram within two imaging planes and three OAM channels in the signal arm is selectively read out and directly displayed on an intensified CMOS camera by switching the OAM state in the idler arm. A thousands-of-times acceleration of the holographic reconstruction process is achieved with the maintenance of the OAM feature for each pixel compared to the scanning approach. The 3D imaging feature in a quantum holography system provides additional freedom for further improving the capacity of holographic information transmission and encryption. Currently, most quantum holography schemes adopt reconstructing images from the second-order correlation information or fiber scanning, which are both non-visualized, meanwhile making three-dimensional (3D) quantum holography a big challenge. Here, we implement the visualized quantum 3D orbital-angular-momentum (OAM) holography in the twin photon system, where the OAM-multiplexing hologram within two imaging planes and three OAM channels in the signal arm is selectively read out and directly displayed on an intensified CMOS camera by switching the OAM state in the idler arm. A thousands-of-times acceleration of the holographic reconstruction process is achieved with the maintenance of the OAM feature for each pixel compared to the scanning approach. The 3D imaging feature in a quantum holography system provides additional freedom for further improving the capacity of holographic information transmission and encryption.
Chinese Optics Letters
- Publication Date: Nov. 08, 2024
- Vol. 22, Issue 11, 110501 (2024)
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