In this paper,we present a Deep Neural Network(DNN)based framework that employs Radio Frequency(RF)hologram tensors to locate multiple Ultra-High Frequency(UHF)passive Radio-Frequency Identification(RFID)tags.The RF h...In this paper,we present a Deep Neural Network(DNN)based framework that employs Radio Frequency(RF)hologram tensors to locate multiple Ultra-High Frequency(UHF)passive Radio-Frequency Identification(RFID)tags.The RF hologram tensor exhibits a strong relationship between observation and spatial location,helping to improve the robustness to dynamic environments and equipment.Since RFID data is often marred by noise,we implement two types of deep neural network architectures to clean up the RF hologram tensor.Leveraging the spatial relationship between tags,the deep networks effectively mitigate fake peaks in the hologram tensors resulting from multipath propagation and phase wrapping.In contrast to fingerprinting-based localization systems that use deep networks as classifiers,our deep networks in the proposed framework treat the localization task as a regression problem preserving the ambiguity between fingerprints.We also present an intuitive peak finding algorithm to obtain estimated locations using the sanitized hologram tensors.The proposed framework is implemented using commodity RFID devices,and its superior performance is validated through extensive experiments.展开更多
Acoustic holograms can recover wavefront stored acoustic field information and produce high-fidelity complex acoustic fields. Benefiting from the huge spatial information that traditional acoustic elements cannot matc...Acoustic holograms can recover wavefront stored acoustic field information and produce high-fidelity complex acoustic fields. Benefiting from the huge spatial information that traditional acoustic elements cannot match, acoustic holograms pursue the realization of high-resolution complex acoustic fields and gradually tend to high-frequency ultrasound applications. However, conventional continuous phase holograms are limited by three-dimensional(3D) printing size, and the presence of unavoidable small printing errors makes it difficult to achieve acoustic field reconstruction at high frequency accuracy. Here, we present an optimized discrete multi-step phase hologram. It can ensure the reconstruction quality of image with high robustness, and properly lower the requirement for the 3D printing accuracy. Meanwhile, the concept of reconstruction similarity is proposed to refine a measure of acoustic field quality. In addition, the realized complex acoustic field at 20 MHz promotes the application of acoustic holograms at high frequencies and provides a new way to generate high-fidelity acoustic fields.展开更多
Computer-generated holography technology has been widely applied,and as research in this field deepens,the demand for memory and computational power in small AR and VR devices continues to increase.This paper presents...Computer-generated holography technology has been widely applied,and as research in this field deepens,the demand for memory and computational power in small AR and VR devices continues to increase.This paper presents a hologram generation method,i.e.,a symmetrically high-compressed look-up table method,which can reduce memory usage by50%.In offline computing,half of the basic horizontal and vertical modulation factors are stored,halving the memory requirements without affecting inline speed.Currently,its potential extends to various holographic applications,including the production of optical diffraction elements.展开更多
An advanced method for rapidly computing holograms of large three-dimensional(3D)objects combines backward ray tracing with adaptive resolution wavefront recording plane(WRP)and adaptive angular spectrum propagation.I...An advanced method for rapidly computing holograms of large three-dimensional(3D)objects combines backward ray tracing with adaptive resolution wavefront recording plane(WRP)and adaptive angular spectrum propagation.In the initial phase,a WRP with adjustable resolution and sampling interval based on the object’s size is defined to capture detailed information from large 3D objects.The second phase employs an adaptive angular spectrum method(ASM)to efficiently compute the propagation from the large-sized WRP to the small-sized computer-generated hologram(CGH).The computation process is accelerated using CUDA and OptiX.Optical experiments confirm that the algorithm can generate high-quality holograms with shadow and occlusion effects at a resolution of 1024×1024 in 29 ms.展开更多
<div style="text-align:justify;"> Metasurfaces have shown great potential in controlling the propagation of electromagnetic waves, making them suitable for holographic beam-shaping elements. Using the ...<div style="text-align:justify;"> Metasurfaces have shown great potential in controlling the propagation of electromagnetic waves, making them suitable for holographic beam-shaping elements. Using the principle of array synthesis, holograms have been realized in microwave frequency to manipulate electromagnetic waves to generate specific field patterns. However, current research is almost based on linear polarization and has little analysis on the circular polarization microwave hologram. Herein, we propose a circular polarization hologram realized by sub-wavelength units with self-adaptively phase profiles of electromagnetic waves. The full, continuous control of the phase is achieved by using a single structure unit based on the Pancharatnam-Berry phase. The inhomogeneity of wave-front is considered through amplitude and phase compensation which are essential to improve the quality of microwave hologram. The model achieves circular polarization hologram in microwave frequency and the clear field pattern is generated. The circular polarization hologram enriched the research field of microwave imaging, thus providing more inspirations for the development of various related techniques. </div>展开更多
The characteristics of optical fiber are quite important for improving the performance of optical fiber communication and sensor systems.Based on the Mach-Zehnder interferometer,a new measuring method is proposed and ...The characteristics of optical fiber are quite important for improving the performance of optical fiber communication and sensor systems.Based on the Mach-Zehnder interferometer,a new measuring method is proposed and the digital holograms between the single mode fibers(SMFs) and specialty double-cladding(DC) fibers are analyzed.The experimental results show that the fringe density can be changed under the conditions of coaxial and off-axial interferences.Therefore it can be used to analyze the optical fiber characteristics including refractive index distribution,fiber modes,phase difference,etc.展开更多
Real time digital recording and numerical reconstruction of a temporal digital hologram sequence have become feasible in recent years.They provide a new measurement method which enjoys the valuable advantages of being...Real time digital recording and numerical reconstruction of a temporal digital hologram sequence have become feasible in recent years.They provide a new measurement method which enjoys the valuable advantages of being full-field,noncontact and high precision.In this paper,a combined method of temporal digital hologram sequence and windowed Fourier transform is proposed to measure the kinematic parameters of random vibration.A series of holograms are recorded by CCD camera and the original phase can be reconstructed by Fresnel reconstruction algorithm.The three-dimensional windowed Fourier transform is used to filter noise in phase and extract the instantaneous kinematic parameters of the specimen,such as the displacement,velocity and acceleration.An experiment is conducted on a chloroprene rubber latex membrane.Results demonstrate that the proposed method determines the vibration parameters precisely and enjoys many merits.展开更多
To study the selective erasure and rewriting of the multiplexed holographic storage inphotorefractive crystals.According to the mechanism on forming of phase hologram in photore-fractive crystal,by incoherently additi...To study the selective erasure and rewriting of the multiplexed holographic storage inphotorefractive crystals.According to the mechanism on forming of phase hologram in photore-fractive crystal,by incoherently addition of the complementary hologram and the original holo-gram,the selective erasure and rewriting were accomplished.The complementary holography isan effective and convenient technique for selective erasure and rewriting of multiplexed holo-graphic storage in photorefractive crystals.展开更多
A phase-only computer-generated holography（CGH） calculation method for stereoscopic holography is proposed in this paper.The two-dimensional（2D） perspective projection views of the three-dimensional（3D） object a...A phase-only computer-generated holography（CGH） calculation method for stereoscopic holography is proposed in this paper.The two-dimensional（2D） perspective projection views of the three-dimensional（3D） object are generated by the computer graphics rendering techniques.Based on these views,a phase-only hologram is calculated by using the Gerchberg–Saxton（GS） iterative algorithm.Comparing with the non-iterative algorithm in the conventional stereoscopic holography,the proposed method improves the holographic image quality,especially for the phase-only hologram encoded from the complex distribution.Both simulation and optical experiment results demonstrate that our proposed method can give higher quality reconstruction comparing with the traditional method.展开更多
To reduce the computing time of composite computer-generated holograms （CGHs） gen- eration based upon the angular projection algorithm for holographic three-dimensional （3D） display, a grid-based holographic displ...To reduce the computing time of composite computer-generated holograms （CGHs） gen- eration based upon the angular projection algorithm for holographic three-dimensional （3D） display, a grid-based holographic display （ GHD ） scheme was designed. The grid computing technology was applied to numerically process the different angular projections of an object in distributed-parallel manner to create the corresponding CGHs. The whole treatment of a projection was regarded as a job executed on the grid node machine. The number of jobs which were submitted to grid nodes, therefore, was equal to that of the projections of the object. A Condor-based grid testbed was constructed to verify the feasibility of the GHD scheme, and a graphical user interface （GUI） program and several service modules were developed for it. A 3D terrain model as an example was processed on the testbed. The result showed that the scheme was feasible and able to improve the execution elficiency greatly.展开更多
Multimodal imaging,including augmented or mixed reality,transforms the physicians’interaction with clinical imaging,allowing more accurate data interpretation,better spatial resolution,and depth perception of the pat...Multimodal imaging,including augmented or mixed reality,transforms the physicians’interaction with clinical imaging,allowing more accurate data interpretation,better spatial resolution,and depth perception of the patient’s anatomy.We successfully overlay 3D holographic visualization to magnetic resonance imaging images for preoperative decision making of a complex case of cardiac tumour in a 7-year-old girl.展开更多
In order to improve femtosecond laser throughput,a parallel processing system consisting of liquid crystal on silicon(LCOS)device as spatial light modulator is put forward.A method is described for displaying Fourier ...In order to improve femtosecond laser throughput,a parallel processing system consisting of liquid crystal on silicon(LCOS)device as spatial light modulator is put forward.A method is described for displaying Fourier hologram on LCOS,and a high uniformity of several diffraction peaks in the computer reconstruction is achieved.Application of this method to the parallel femtosecond laser processing is also demonstrated,and two intersecting rings and three tangent rings are fabricated respectively by one time in the photoresist.展开更多
Holograms provide a characteristic manner to display and convey information, and have been improved to provide better user interactions Holographic interactions are important as they improve user interactions with vir...Holograms provide a characteristic manner to display and convey information, and have been improved to provide better user interactions Holographic interactions are important as they improve user interactions with virtual objects. Gesture interaction is a recent research topic, as it allows users to use their bare hands to directly interact with the hologram. However, it remains unclear whether real hand gestures are well suited for hologram applications. Therefore, we discuss the development process and implementation of three-dimensional object manipulation using natural hand gestures in a hologram. We describe the design and development process for hologram applications and its integration with real hand gesture interactions as initial findings. Experimental results from Nasa TLX form are discussed. Based on the findings, we actualize the user interactions in the hologram.展开更多
Holographic recording analysis was performed on the films that were sensitized with ammonium dichromate with albumin of hen and quail (Gallus gallus and Callipepla cali) as abiopolymeric photosensitive matrix. The sam...Holographic recording analysis was performed on the films that were sensitized with ammonium dichromate with albumin of hen and quail (Gallus gallus and Callipepla cali) as abiopolymeric photosensitive matrix. The samples were exposed to an He-Cd laser, λ = 442 nm, at various concentrations, and diffraction efficiencies were measured as a function to the energy, thickness, protein density, aging time, and spatial frequencies. The photosensitivity was measured as a function of storage time, and the gratings were recorded in real time. The photochemical processes involved in the formation of holographic image are described. The results indicate the behavior of colloidal systems based on albumin bird build holographic recording materials.展开更多
Diffractive optical elements have a large number of industrial applications, such as beam shaping and optical filtering. Traditionally, these elements modulate the phase of the incoming light or its amplitude, but not...Diffractive optical elements have a large number of industrial applications, such as beam shaping and optical filtering. Traditionally, these elements modulate the phase of the incoming light or its amplitude, but not both. To overcome this limitation, full complex-amplitude modulation diffractive optical elements were developed. Well-established integrated circuit fabrication steps were employed to fabricate the devices with high precision. Using this approach, the new element's optical performances are improved also for near field operations. With this device it is possible to obtain 100% efficient spatial filtering and low noise reconstructed images.展开更多
Ultracompact metasurfaces have gained a high reputation for manipulating light fields precisely within a subwavelength scale,bringing great development to the fields of nanophotonics,integrated optics,and quantum tech...Ultracompact metasurfaces have gained a high reputation for manipulating light fields precisely within a subwavelength scale,bringing great development to the fields of nanophotonics,integrated optics,and quantum technology.There is broad interest in expanding the working band of metasurfaces to expand functionalities and the scope of applications.However,increasing the number of working wavelengths multiplexed in a single holographic metasurface is always complicated by two vital issues,i.e.,spectral cross talk and the efficiency imbalance between different wavelength channels.Therefore,holographic metasurfaces with multiplexed working wavelengths over three are seldom reported.To address these two issues,we present a design strategy based on unevenly distributed pixels(UEDPs).As a proof of concept,a UEDP-based metasurface is designed to offer a camouflage method to hide four encrypted holographic images in a multicolor printed image.Our results not only demonstrate the idea of UEDP as an easy-to-implement and effective way for strengthening the wavelength multiplexing of metasurfaces but also give rise to a camouflage metasurface by integrating high-capacity and high-security encrypted holographic information with a single printed image.We believe that the generic UEDP-based metasurface design strategy can be readily extended to the realization of artificial functional structures in various disciplines,such as optics,thermology,and acoustics.展开更多
With the escalating laser peak power,modulating and detecting the intensity,duration,phase and polarization of ultraintense laser pulses progressively becomes increasingly arduous due to the limited damage thresholds ...With the escalating laser peak power,modulating and detecting the intensity,duration,phase and polarization of ultraintense laser pulses progressively becomes increasingly arduous due to the limited damage thresholds of conventional optical components.In particular,the generation and detection of ultra-intense vortex lasers pose great challenges for current laser technologies,which has limited the widely potential applications of relativistic vortex lasers in various domains.In this study,we propose to reconstruct the vortex phase and generate and amplify the relativistic vortex lasers via surface plasma holograms(SPHs).By interfering with the object laser and reference laser,SPHs are formed on the target and the phase of the interfering laser is imprinted through the modulation of surface plasma density.In particular,using the quadrature phase-shift interference,the vortex phase of the object laser can be well reconstructed.The generated vortex lasers can be focused and enhanced further by one order of magnitude,up to 1.7×10^(21)W/cm^(2),which has been demonstrated by full three-dimensional particle-in-cell simulations.For the first time,we provide a practical way to detect the phase of relativistic vortex lasers,which can be applied in large 1–10 PW laser facilities.This will promote future experimental research of vortex-laser–plasma interaction and open a new avenue of plasma optics in the ultra-relativistic regime.展开更多
In this paper,we propose a novel complex-valued hierarchical multi-fusion neural network(CHMFNet)for generating highquality holograms.The proposed architecture builds upon a U-Net framework,incorporating a complex-val...In this paper,we propose a novel complex-valued hierarchical multi-fusion neural network(CHMFNet)for generating highquality 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.展开更多
Coherence preserves phase consistency between wavefields,enabling accurate recording and reconstruction in holography.Although recent advances in computational optics have realized holographic data acquisition using i...Coherence preserves phase consistency between wavefields,enabling accurate recording and reconstruction in holography.Although recent advances in computational optics have realized holographic data acquisition using incoherent light by computationally retrieving information,optical reconstruction still requires partially coherent light sources.We demonstrate a hologram that reconstructs 3-dimensional distribution utilizing incoherence.By decomposing incoherent light into infinitesimal coherent lights and calculating their propagations,the incoherent sum is optimized to resemble the desired 3-dimensional scene,whereas individual coherent lights reconstruct completely different intensities.Incoherence provides high image quality and a wide eyebox,with the reconstructed intensity remaining shift-invariant under pupil displacement,allowing a 1000-fold expansion of the eyebox.We confirm the shift-invariance through a proof-of-concept experiment and demonstrate real-time synthesis of incoherent holograms using a neural network,significantly reducing computational costs.Our method could inspire new approaches in photonics using incoherent light and be practically adopted in holographic displays.展开更多
As a frontier technology,holography has important research values in fields such as bio-micrographic imaging,light feld modulation and data storage.However,the real-time acquisition of 3D scenes and high-fidelity reco...As a frontier technology,holography has important research values in fields such as bio-micrographic imaging,light feld modulation and data storage.However,the real-time acquisition of 3D scenes and high-fidelity reconstruction technology has not yet made a breakthrough,which has seriously hindered the development of holography.Here,a novel holographic camera is proposed to solve the above inherent problems completely.The proposed holographic camera consists of the acquisition end and the calculation end.At the acquisition end of the holographic camera,specially configured liquid materials and liquid lens structure based on voice-coil motor-driving are used to produce the liquid camera,so that the liquid camera can quickly capture the focus stack of the real 3D scene within 15 ms.At the calculation end,a new structured focus stack network(FS-Net)is designed for hologram calculation.After training the FS-Net with the focus stack renderer and learnable Zernike phase,it enables hologram calculation within 13 ms.As the first device to achieve real-time incoherent acquisition and high-fidelity holographic reconstruction of a real 3D scene,our proposed holographic camera breaks technical bottlenecks of difficulty in acquiring the real 3D scene,low quality of the holographic reconstructed image,and incorrect defocus blur.The experimental results demonstrate the effectiveness of our holographic camera in the acquisition of focal plane information and hologram calculation of the real 3D scene.The proposed holographic camera opens up a new way for the application of holography in fields such as 3D display,light field modulation,and 3D measurement.展开更多
基金supported in part by the U.S.National Science Foundation(NSF)under Grants ECCS-2245608 and ECCS-2245607。
文摘In this paper,we present a Deep Neural Network(DNN)based framework that employs Radio Frequency(RF)hologram tensors to locate multiple Ultra-High Frequency(UHF)passive Radio-Frequency Identification(RFID)tags.The RF hologram tensor exhibits a strong relationship between observation and spatial location,helping to improve the robustness to dynamic environments and equipment.Since RFID data is often marred by noise,we implement two types of deep neural network architectures to clean up the RF hologram tensor.Leveraging the spatial relationship between tags,the deep networks effectively mitigate fake peaks in the hologram tensors resulting from multipath propagation and phase wrapping.In contrast to fingerprinting-based localization systems that use deep networks as classifiers,our deep networks in the proposed framework treat the localization task as a regression problem preserving the ambiguity between fingerprints.We also present an intuitive peak finding algorithm to obtain estimated locations using the sanitized hologram tensors.The proposed framework is implemented using commodity RFID devices,and its superior performance is validated through extensive experiments.
基金Project supported by the China Postdoctoral Science Foundation (Grant No.2023M732745)the National Natural Science Foundations of China (Grant Nos.61974110 and 62104177)+1 种基金the Fundamental Research Funds for the Central Universities,China (Grant Nos.QTZX23022 and JBF211103)the Cooperation Program of XDU– Chongqing IC Innovation Research Institute (Grant No.CQ IRI-2022CXY-Z07)。
文摘Acoustic holograms can recover wavefront stored acoustic field information and produce high-fidelity complex acoustic fields. Benefiting from the huge spatial information that traditional acoustic elements cannot match, acoustic holograms pursue the realization of high-resolution complex acoustic fields and gradually tend to high-frequency ultrasound applications. However, conventional continuous phase holograms are limited by three-dimensional(3D) printing size, and the presence of unavoidable small printing errors makes it difficult to achieve acoustic field reconstruction at high frequency accuracy. Here, we present an optimized discrete multi-step phase hologram. It can ensure the reconstruction quality of image with high robustness, and properly lower the requirement for the 3D printing accuracy. Meanwhile, the concept of reconstruction similarity is proposed to refine a measure of acoustic field quality. In addition, the realized complex acoustic field at 20 MHz promotes the application of acoustic holograms at high frequencies and provides a new way to generate high-fidelity acoustic fields.
基金Project supported by the National Natural Science Foundation of China (Grant No.62205350)the Special Project of Central Government Guiding Local Science and Technology Development in Beijing 2020 (Grant No.Z20111000430000)the Guangxi Nanning Key R&D Program (Grant No.20233067)。
文摘Computer-generated holography technology has been widely applied,and as research in this field deepens,the demand for memory and computational power in small AR and VR devices continues to increase.This paper presents a hologram generation method,i.e.,a symmetrically high-compressed look-up table method,which can reduce memory usage by50%.In offline computing,half of the basic horizontal and vertical modulation factors are stored,halving the memory requirements without affecting inline speed.Currently,its potential extends to various holographic applications,including the production of optical diffraction elements.
基金Project supported by the Special Project of Central Government Guiding Local Science and Technology Development in Beijing 2020(Grant No.Z201100004320006).
文摘An advanced method for rapidly computing holograms of large three-dimensional(3D)objects combines backward ray tracing with adaptive resolution wavefront recording plane(WRP)and adaptive angular spectrum propagation.In the initial phase,a WRP with adjustable resolution and sampling interval based on the object’s size is defined to capture detailed information from large 3D objects.The second phase employs an adaptive angular spectrum method(ASM)to efficiently compute the propagation from the large-sized WRP to the small-sized computer-generated hologram(CGH).The computation process is accelerated using CUDA and OptiX.Optical experiments confirm that the algorithm can generate high-quality holograms with shadow and occlusion effects at a resolution of 1024×1024 in 29 ms.
文摘<div style="text-align:justify;"> Metasurfaces have shown great potential in controlling the propagation of electromagnetic waves, making them suitable for holographic beam-shaping elements. Using the principle of array synthesis, holograms have been realized in microwave frequency to manipulate electromagnetic waves to generate specific field patterns. However, current research is almost based on linear polarization and has little analysis on the circular polarization microwave hologram. Herein, we propose a circular polarization hologram realized by sub-wavelength units with self-adaptively phase profiles of electromagnetic waves. The full, continuous control of the phase is achieved by using a single structure unit based on the Pancharatnam-Berry phase. The inhomogeneity of wave-front is considered through amplitude and phase compensation which are essential to improve the quality of microwave hologram. The model achieves circular polarization hologram in microwave frequency and the clear field pattern is generated. The circular polarization hologram enriched the research field of microwave imaging, thus providing more inspirations for the development of various related techniques. </div>
基金supported by the Key Program of the National Natural Science Foundation of China (No.60937003)the Science and Technology Commission of Shanghai Municipality (STCSM) (No.0952nm06800)
文摘The characteristics of optical fiber are quite important for improving the performance of optical fiber communication and sensor systems.Based on the Mach-Zehnder interferometer,a new measuring method is proposed and the digital holograms between the single mode fibers(SMFs) and specialty double-cladding(DC) fibers are analyzed.The experimental results show that the fringe density can be changed under the conditions of coaxial and off-axial interferences.Therefore it can be used to analyze the optical fiber characteristics including refractive index distribution,fiber modes,phase difference,etc.
基金supported by the National Natural Science Foundation of China (10772171 and 10732080)the National Basic Research Program of China (2007CB936803)
文摘Real time digital recording and numerical reconstruction of a temporal digital hologram sequence have become feasible in recent years.They provide a new measurement method which enjoys the valuable advantages of being full-field,noncontact and high precision.In this paper,a combined method of temporal digital hologram sequence and windowed Fourier transform is proposed to measure the kinematic parameters of random vibration.A series of holograms are recorded by CCD camera and the original phase can be reconstructed by Fresnel reconstruction algorithm.The three-dimensional windowed Fourier transform is used to filter noise in phase and extract the instantaneous kinematic parameters of the specimen,such as the displacement,velocity and acceleration.An experiment is conducted on a chloroprene rubber latex membrane.Results demonstrate that the proposed method determines the vibration parameters precisely and enjoys many merits.
文摘To study the selective erasure and rewriting of the multiplexed holographic storage inphotorefractive crystals.According to the mechanism on forming of phase hologram in photore-fractive crystal,by incoherently addition of the complementary hologram and the original holo-gram,the selective erasure and rewriting were accomplished.The complementary holography isan effective and convenient technique for selective erasure and rewriting of multiplexed holo-graphic storage in photorefractive crystals.
基金Project supported by the National Basic Research Program of China(Grant No.2013CB328803)the National High Technology Research and Development Program of China(Grant Nos.2013AA013904 and 2015AA016301)
文摘A phase-only computer-generated holography（CGH） calculation method for stereoscopic holography is proposed in this paper.The two-dimensional（2D） perspective projection views of the three-dimensional（3D） object are generated by the computer graphics rendering techniques.Based on these views,a phase-only hologram is calculated by using the Gerchberg–Saxton（GS） iterative algorithm.Comparing with the non-iterative algorithm in the conventional stereoscopic holography,the proposed method improves the holographic image quality,especially for the phase-only hologram encoded from the complex distribution.Both simulation and optical experiment results demonstrate that our proposed method can give higher quality reconstruction comparing with the traditional method.
文摘To reduce the computing time of composite computer-generated holograms （CGHs） gen- eration based upon the angular projection algorithm for holographic three-dimensional （3D） display, a grid-based holographic display （ GHD ） scheme was designed. The grid computing technology was applied to numerically process the different angular projections of an object in distributed-parallel manner to create the corresponding CGHs. The whole treatment of a projection was regarded as a job executed on the grid node machine. The number of jobs which were submitted to grid nodes, therefore, was equal to that of the projections of the object. A Condor-based grid testbed was constructed to verify the feasibility of the GHD scheme, and a graphical user interface （GUI） program and several service modules were developed for it. A 3D terrain model as an example was processed on the testbed. The result showed that the scheme was feasible and able to improve the execution elficiency greatly.
文摘Multimodal imaging,including augmented or mixed reality,transforms the physicians’interaction with clinical imaging,allowing more accurate data interpretation,better spatial resolution,and depth perception of the patient’s anatomy.We successfully overlay 3D holographic visualization to magnetic resonance imaging images for preoperative decision making of a complex case of cardiac tumour in a 7-year-old girl.
基金National Natural Science Foundation of China(No.51275502)Natural Science Key Project of Anhui Province(No.KJ2011A014)+1 种基金China Postdoctoral Science Foundation funded project(NO.2012M511416)The Innovation Foundationof Anhui University and the Personnel Construction Project of Anhui University
文摘In order to improve femtosecond laser throughput,a parallel processing system consisting of liquid crystal on silicon(LCOS)device as spatial light modulator is put forward.A method is described for displaying Fourier hologram on LCOS,and a high uniformity of several diffraction peaks in the computer reconstruction is achieved.Application of this method to the parallel femtosecond laser processing is also demonstrated,and two intersecting rings and three tangent rings are fabricated respectively by one time in the photoresist.
文摘Holograms provide a characteristic manner to display and convey information, and have been improved to provide better user interactions Holographic interactions are important as they improve user interactions with virtual objects. Gesture interaction is a recent research topic, as it allows users to use their bare hands to directly interact with the hologram. However, it remains unclear whether real hand gestures are well suited for hologram applications. Therefore, we discuss the development process and implementation of three-dimensional object manipulation using natural hand gestures in a hologram. We describe the design and development process for hologram applications and its integration with real hand gesture interactions as initial findings. Experimental results from Nasa TLX form are discussed. Based on the findings, we actualize the user interactions in the hologram.
基金Thanks are due to The Instituto Nacional de Astrofisica Optica y Electronica(INAOE)for the infrastructure and economic support received.
文摘Holographic recording analysis was performed on the films that were sensitized with ammonium dichromate with albumin of hen and quail (Gallus gallus and Callipepla cali) as abiopolymeric photosensitive matrix. The samples were exposed to an He-Cd laser, λ = 442 nm, at various concentrations, and diffraction efficiencies were measured as a function to the energy, thickness, protein density, aging time, and spatial frequencies. The photosensitivity was measured as a function of storage time, and the gratings were recorded in real time. The photochemical processes involved in the formation of holographic image are described. The results indicate the behavior of colloidal systems based on albumin bird build holographic recording materials.
文摘Diffractive optical elements have a large number of industrial applications, such as beam shaping and optical filtering. Traditionally, these elements modulate the phase of the incoming light or its amplitude, but not both. To overcome this limitation, full complex-amplitude modulation diffractive optical elements were developed. Well-established integrated circuit fabrication steps were employed to fabricate the devices with high precision. Using this approach, the new element's optical performances are improved also for near field operations. With this device it is possible to obtain 100% efficient spatial filtering and low noise reconstructed images.
基金supported by the Innovation and Technology Commission of Hong Kong(Grant No.GHP/026/19GD)the Research Grants Council of Hong Kong(Grant No.Ao E/P-502/20)+3 种基金the National Key R&D Program of China(Grant No.2021YFA1400804)the National Natural Science Foundation of China(Grant No.12222415)the Guangdong Natural Science Fund(Grant Nos.2024B1515040013 and 2020A0505140004)the Guangdong Provincial Quantum Science Strategic Initiative(Grant No.GDZX2305005)。
文摘Ultracompact metasurfaces have gained a high reputation for manipulating light fields precisely within a subwavelength scale,bringing great development to the fields of nanophotonics,integrated optics,and quantum technology.There is broad interest in expanding the working band of metasurfaces to expand functionalities and the scope of applications.However,increasing the number of working wavelengths multiplexed in a single holographic metasurface is always complicated by two vital issues,i.e.,spectral cross talk and the efficiency imbalance between different wavelength channels.Therefore,holographic metasurfaces with multiplexed working wavelengths over three are seldom reported.To address these two issues,we present a design strategy based on unevenly distributed pixels(UEDPs).As a proof of concept,a UEDP-based metasurface is designed to offer a camouflage method to hide four encrypted holographic images in a multicolor printed image.Our results not only demonstrate the idea of UEDP as an easy-to-implement and effective way for strengthening the wavelength multiplexing of metasurfaces but also give rise to a camouflage metasurface by integrating high-capacity and high-security encrypted holographic information with a single printed image.We believe that the generic UEDP-based metasurface design strategy can be readily extended to the realization of artificial functional structures in various disciplines,such as optics,thermology,and acoustics.
基金supported by the National Natural Science Foundation of China(Grant Nos.12375244,12305265,12135009 and 12174047)the Natural Science Foundation of Hunan Province of China(Grant No.2025JJ30002)。
文摘With the escalating laser peak power,modulating and detecting the intensity,duration,phase and polarization of ultraintense laser pulses progressively becomes increasingly arduous due to the limited damage thresholds of conventional optical components.In particular,the generation and detection of ultra-intense vortex lasers pose great challenges for current laser technologies,which has limited the widely potential applications of relativistic vortex lasers in various domains.In this study,we propose to reconstruct the vortex phase and generate and amplify the relativistic vortex lasers via surface plasma holograms(SPHs).By interfering with the object laser and reference laser,SPHs are formed on the target and the phase of the interfering laser is imprinted through the modulation of surface plasma density.In particular,using the quadrature phase-shift interference,the vortex phase of the object laser can be well reconstructed.The generated vortex lasers can be focused and enhanced further by one order of magnitude,up to 1.7×10^(21)W/cm^(2),which has been demonstrated by full three-dimensional particle-in-cell simulations.For the first time,we provide a practical way to detect the phase of relativistic vortex lasers,which can be applied in large 1–10 PW laser facilities.This will promote future experimental research of vortex-laser–plasma interaction and open a new avenue of plasma optics in the ultra-relativistic regime.
基金supported by the National Natural Science Foundation of China(No.62265006)the Jiangxi Provincial Department of Science and Technology(Nos.20212BCJL23050 and 20232BAB212017)+4 种基金the Natural Science Foundation of Zhejiang Province(No.LQ22F050005)the Fundamental Research Funds for the Provincial Universities of Zhejiang(No.2022YW53)the Foundation of Jiangxi Educational Commission(No.GJJ200623)the China Postdoctoral Science Foundation(No.2021M691344)the Jiangxi Provincial Postdoctoral Science Foundation of China(No.2020KY16)。
文摘In this paper,we propose a novel complex-valued hierarchical multi-fusion neural network(CHMFNet)for generating highquality 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.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(No.RS-2023-00245184 and RS-2024-00341142)。
文摘Coherence preserves phase consistency between wavefields,enabling accurate recording and reconstruction in holography.Although recent advances in computational optics have realized holographic data acquisition using incoherent light by computationally retrieving information,optical reconstruction still requires partially coherent light sources.We demonstrate a hologram that reconstructs 3-dimensional distribution utilizing incoherence.By decomposing incoherent light into infinitesimal coherent lights and calculating their propagations,the incoherent sum is optimized to resemble the desired 3-dimensional scene,whereas individual coherent lights reconstruct completely different intensities.Incoherence provides high image quality and a wide eyebox,with the reconstructed intensity remaining shift-invariant under pupil displacement,allowing a 1000-fold expansion of the eyebox.We confirm the shift-invariance through a proof-of-concept experiment and demonstrate real-time synthesis of incoherent holograms using a neural network,significantly reducing computational costs.Our method could inspire new approaches in photonics using incoherent light and be practically adopted in holographic displays.
基金supported by National Natural Science Foundation of China(U22A2079,62275009,62175006,and U21B2034).
文摘As a frontier technology,holography has important research values in fields such as bio-micrographic imaging,light feld modulation and data storage.However,the real-time acquisition of 3D scenes and high-fidelity reconstruction technology has not yet made a breakthrough,which has seriously hindered the development of holography.Here,a novel holographic camera is proposed to solve the above inherent problems completely.The proposed holographic camera consists of the acquisition end and the calculation end.At the acquisition end of the holographic camera,specially configured liquid materials and liquid lens structure based on voice-coil motor-driving are used to produce the liquid camera,so that the liquid camera can quickly capture the focus stack of the real 3D scene within 15 ms.At the calculation end,a new structured focus stack network(FS-Net)is designed for hologram calculation.After training the FS-Net with the focus stack renderer and learnable Zernike phase,it enables hologram calculation within 13 ms.As the first device to achieve real-time incoherent acquisition and high-fidelity holographic reconstruction of a real 3D scene,our proposed holographic camera breaks technical bottlenecks of difficulty in acquiring the real 3D scene,low quality of the holographic reconstructed image,and incorrect defocus blur.The experimental results demonstrate the effectiveness of our holographic camera in the acquisition of focal plane information and hologram calculation of the real 3D scene.The proposed holographic camera opens up a new way for the application of holography in fields such as 3D display,light field modulation,and 3D measurement.
