Pub Date : 2022-03-04DOI: 10.3389/fphot.2022.904651
Emil Z. Ulsig, I. Degli-Eredi, E. Stanton, N. Volet
A design study is presented for an efficient, compact and robust device to convert the frequency of single-photons from the near-infrared to the telecom C-band. The material platform aluminum gallium arsenide (AlGaAs)-on-insulator, with its relatively large second-order nonlinearity, is used to create highly confined optical modes. This platform can feasibly incorporate single-photon emitters such as indium arsenide (InAs) on gallium arsenide (GaAs), paving the way towards direct integration of single-photon sources and nonlinear waveguides on the same chip. In this design study, single-pass difference-frequency generation (DFG) producing C-band single-photons is enabled via form birefringent phase-matching between a 930 nm single-photon pump and continuous wave (CW) idler at 2,325 nm. In particular the idler and single-photons are combined with an on-chip directional coupler, and then tapered to a single waveguide where the three modes are phase-matched. The design is studied at a special case, showing high fabrication tolerances, and an internal conversion efficiency up to 41%.
{"title":"Efficient Low Threshold Frequency Conversion in AlGaAs-On-Insulator Waveguides","authors":"Emil Z. Ulsig, I. Degli-Eredi, E. Stanton, N. Volet","doi":"10.3389/fphot.2022.904651","DOIUrl":"https://doi.org/10.3389/fphot.2022.904651","url":null,"abstract":"A design study is presented for an efficient, compact and robust device to convert the frequency of single-photons from the near-infrared to the telecom C-band. The material platform aluminum gallium arsenide (AlGaAs)-on-insulator, with its relatively large second-order nonlinearity, is used to create highly confined optical modes. This platform can feasibly incorporate single-photon emitters such as indium arsenide (InAs) on gallium arsenide (GaAs), paving the way towards direct integration of single-photon sources and nonlinear waveguides on the same chip. In this design study, single-pass difference-frequency generation (DFG) producing C-band single-photons is enabled via form birefringent phase-matching between a 930 nm single-photon pump and continuous wave (CW) idler at 2,325 nm. In particular the idler and single-photons are combined with an on-chip directional coupler, and then tapered to a single waveguide where the three modes are phase-matched. The design is studied at a special case, showing high fabrication tolerances, and an internal conversion efficiency up to 41%.","PeriodicalId":73099,"journal":{"name":"Frontiers in photonics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49267386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-02DOI: 10.3389/fphot.2022.834065
Anahita Khodadad Kashi, L. Sader, R. Haldar, B. Wetzel, M. Kues
The well-established frequency-to-time mapping technique is employed as a convenient and time-efficient method to directly characterize the spectral correlations of biphoton states from a pulsed-excited spontaneous parametric down-conversion process. We were enabled by this technique to implement for the first time, the spectral Hanbury-Brown and Twiss measurement, revealing directly the single frequency-mode bandwidth of the biphoton state.
{"title":"Frequency-to-Time Mapping Technique for Direct Spectral Characterization of Biphoton States From Pulsed Spontaneous Parametric Processes","authors":"Anahita Khodadad Kashi, L. Sader, R. Haldar, B. Wetzel, M. Kues","doi":"10.3389/fphot.2022.834065","DOIUrl":"https://doi.org/10.3389/fphot.2022.834065","url":null,"abstract":"The well-established frequency-to-time mapping technique is employed as a convenient and time-efficient method to directly characterize the spectral correlations of biphoton states from a pulsed-excited spontaneous parametric down-conversion process. We were enabled by this technique to implement for the first time, the spectral Hanbury-Brown and Twiss measurement, revealing directly the single frequency-mode bandwidth of the biphoton state.","PeriodicalId":73099,"journal":{"name":"Frontiers in photonics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45478718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-01DOI: 10.3389/fphot.2022.886354
A. Gottscholl, M. Wagenhöfer, Manuel Klimmer, Selina Scherbel, C. Kasper, V. Baianov, G. Astakhov, V. Dyakonov, A. Sperlich
Masers as telecommunication amplifiers have been known for decades, yet their application is strongly limited due to extreme operating conditions requiring vacuum techniques and cryogenic temperatures. Recently, a new generation of masers has been invented based on optically pumped spin states in pentacene and diamond. In this study, we pave the way for masers based on spin S = 3/2 silicon vacancy (VSi) defects in silicon carbide (SiC) to overcome the microwave generation threshold and discuss the advantages of this highly developed spin hosting material. To achieve population inversion, we optically pump the VSi into their m S = ±1/2 spin sub-states and additionally tune the Zeeman energy splitting by applying an external magnetic field. In this way, the prerequisites for stimulated emission by means of resonant microwaves in the 10 GHz range are fulfilled. On the way to realising a maser, we were able to systematically solve a series of subtasks that improved the underlying relevant physical parameters of the SiC samples. Among others, we investigated the pump efficiency as a function of the optical excitation wavelength and the angle between the magnetic field and the defect symmetry axis in order to boost the population inversion factor, a key figure of merit for the targeted microwave oscillator. Furthermore, we developed a high-Q sapphire microwave resonator (Q ≈ 104–105) with which we find superradiant stimulated microwave emission. In summary, SiC with optimized spin defect density and thus spin relaxation rates is well on its way of becoming a suitable maser gain material with wide-ranging applications.
微波激射器作为电信放大器已经存在了几十年，但由于需要真空技术和低温的极端操作条件，它们的应用受到强烈限制。近年来，新一代的脉泽是基于并五苯和金刚石的光抽运自旋态而发明的。在本研究中，我们为基于碳化硅(SiC)中自旋S = 3/2硅空位(VSi)缺陷的脉塞克服微波产生阈值铺平了道路，并讨论了这种高度发展的自旋载体材料的优点。为了实现粒子数反转，我们将VSi光泵入其m S =±1/2自旋子态，并通过施加外部磁场来调节塞曼能量分裂。这样，在10ghz范围内实现谐振微波受激发射的先决条件就得到了满足。在实现脉泽的过程中，我们能够系统地解决一系列子任务，这些子任务改善了SiC样品的基本相关物理参数。其中，我们研究了泵浦效率与光激发波长和磁场与缺陷对称轴之间的夹角的函数关系，以提高目标微波振荡器的关键性能指标——人口反演因子。此外，我们开发了一个高Q蓝宝石微波谐振器(Q≈104-105)，我们发现了超辐射激发的微波发射。综上所述，具有优化自旋缺陷密度和自旋松弛率的碳化硅将成为一种具有广泛应用前景的微波激射增益材料。
{"title":"Superradiance of Spin Defects in Silicon Carbide for Maser Applications","authors":"A. Gottscholl, M. Wagenhöfer, Manuel Klimmer, Selina Scherbel, C. Kasper, V. Baianov, G. Astakhov, V. Dyakonov, A. Sperlich","doi":"10.3389/fphot.2022.886354","DOIUrl":"https://doi.org/10.3389/fphot.2022.886354","url":null,"abstract":"Masers as telecommunication amplifiers have been known for decades, yet their application is strongly limited due to extreme operating conditions requiring vacuum techniques and cryogenic temperatures. Recently, a new generation of masers has been invented based on optically pumped spin states in pentacene and diamond. In this study, we pave the way for masers based on spin S = 3/2 silicon vacancy (VSi) defects in silicon carbide (SiC) to overcome the microwave generation threshold and discuss the advantages of this highly developed spin hosting material. To achieve population inversion, we optically pump the VSi into their m S = ±1/2 spin sub-states and additionally tune the Zeeman energy splitting by applying an external magnetic field. In this way, the prerequisites for stimulated emission by means of resonant microwaves in the 10 GHz range are fulfilled. On the way to realising a maser, we were able to systematically solve a series of subtasks that improved the underlying relevant physical parameters of the SiC samples. Among others, we investigated the pump efficiency as a function of the optical excitation wavelength and the angle between the magnetic field and the defect symmetry axis in order to boost the population inversion factor, a key figure of merit for the targeted microwave oscillator. Furthermore, we developed a high-Q sapphire microwave resonator (Q ≈ 104–105) with which we find superradiant stimulated microwave emission. In summary, SiC with optimized spin defect density and thus spin relaxation rates is well on its way of becoming a suitable maser gain material with wide-ranging applications.","PeriodicalId":73099,"journal":{"name":"Frontiers in photonics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44536086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-25DOI: 10.3389/fphot.2022.835962
Ni Chen , Congli Wang, W. Heidrich
Holographic display is an ultimate three-dimensional (3D) display technique that can produce the wavefront of 3D objects. The dynamic holographic display usually requires a spatial light modulator (SLM) with a following 4f system to eliminate the unnecessary orders produced by the grating structure of the SLM. We present a technique that displays the images without the 4f system. We detect the unnecessary wavefield by phase-shifting holography and suppress it using computational optimization. Experimental results are presented to verify the proposed method.
{"title":"Compact Computational Holographic Display (Invited Article)","authors":"Ni Chen , Congli Wang, W. Heidrich","doi":"10.3389/fphot.2022.835962","DOIUrl":"https://doi.org/10.3389/fphot.2022.835962","url":null,"abstract":"Holographic display is an ultimate three-dimensional (3D) display technique that can produce the wavefront of 3D objects. The dynamic holographic display usually requires a spatial light modulator (SLM) with a following 4f system to eliminate the unnecessary orders produced by the grating structure of the SLM. We present a technique that displays the images without the 4f system. We detect the unnecessary wavefield by phase-shifting holography and suppress it using computational optimization. Experimental results are presented to verify the proposed method.","PeriodicalId":73099,"journal":{"name":"Frontiers in photonics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44232295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-21DOI: 10.3389/fphot.2022.831267
Yu Zhao, Yuan Huang, Liming Zhu, Jingjie Bu, Yueyang Du, M. Zhu, Jin-Rong Zhu
The large amount of computing data from hologram calculations incurs a heavy computational load for realistic full-color holographic displays. In this research, we propose a segmented point-cloud gridding (S-PCG) method to enhance the computing ability of a full-color holographic system. A depth camera is used to collect the color and depth information from actual scenes, which are then reconstructed into the point-cloud model. Object points are categorized into depth grids with identical depth values in the red, green, and blue (RGB) channels. In each channel, the depth grids are segmented into M×N parts, and only the effective area of the depth grids will be calculated. Computer-generated holograms (CGHs) are generated from efficient depth grids by using a fast Fourier transform (FFT). Compared to the wavefront recording plane (WRP) and traditional PCG methods, the computational complexity is dramatically reduced. The feasibility of the S-PCG approach is established through numerical simulations and optical reconstructions.
{"title":"Segmented Point Cloud Gridding Method for a Full-Color Holographic System With Real Objects","authors":"Yu Zhao, Yuan Huang, Liming Zhu, Jingjie Bu, Yueyang Du, M. Zhu, Jin-Rong Zhu","doi":"10.3389/fphot.2022.831267","DOIUrl":"https://doi.org/10.3389/fphot.2022.831267","url":null,"abstract":"The large amount of computing data from hologram calculations incurs a heavy computational load for realistic full-color holographic displays. In this research, we propose a segmented point-cloud gridding (S-PCG) method to enhance the computing ability of a full-color holographic system. A depth camera is used to collect the color and depth information from actual scenes, which are then reconstructed into the point-cloud model. Object points are categorized into depth grids with identical depth values in the red, green, and blue (RGB) channels. In each channel, the depth grids are segmented into M×N parts, and only the effective area of the depth grids will be calculated. Computer-generated holograms (CGHs) are generated from efficient depth grids by using a fast Fourier transform (FFT). Compared to the wavefront recording plane (WRP) and traditional PCG methods, the computational complexity is dramatically reduced. The feasibility of the S-PCG approach is established through numerical simulations and optical reconstructions.","PeriodicalId":73099,"journal":{"name":"Frontiers in photonics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43235425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We propose to reconstruct 3D images by combining the merits of transport of intensity and digital holography. The proposed method solves the transport-of-intensity equation by using digital holographic reconstructed images as inputs. Our simulation and experimental results show that this method can eliminate quadratic phase aberration introduced by the microscope objective in digital holographic microscopy. This proposed phase retrieval method is free of phase unwrapping process. It is thus efficient in removing quadratic phase aberration introduced by the microscope objective.
{"title":"Elimination of Quadratic Phase Aberration in Digital Holographic Microscopy by Using Transport of Intensity","authors":"Wenjing Zhou, Shi-Chang Liu, Chen Wang, Hongbo Zhang, Yingjie Yu, T. Poon","doi":"10.3389/fphot.2022.848453","DOIUrl":"https://doi.org/10.3389/fphot.2022.848453","url":null,"abstract":"We propose to reconstruct 3D images by combining the merits of transport of intensity and digital holography. The proposed method solves the transport-of-intensity equation by using digital holographic reconstructed images as inputs. Our simulation and experimental results show that this method can eliminate quadratic phase aberration introduced by the microscope objective in digital holographic microscopy. This proposed phase retrieval method is free of phase unwrapping process. It is thus efficient in removing quadratic phase aberration introduced by the microscope objective.","PeriodicalId":73099,"journal":{"name":"Frontiers in photonics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42894855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-01DOI: 10.3389/fphot.2021.829139
T. Tahara
We review advancements in incoherent digital holography (IDH) with an image sensor and its applications to multidimensional microscopy and a palm-sized hologram recorder termed “holosensor”. There are two types of representative IDH technique: IDH with a structured illumination and a single photodetector termed optical scanning holography and self-interference IDH. The latter IDH is a technique to obtain an incoherent digital hologram by modulating an incoherent light wave between an object and an image sensor. Multidimensional information such as three-dimensional space and wavelengths is simultaneously recorded without changing optical filters by introducing interferometric techniques invented in laser holography. Applications to high-speed color-multiplexed holographic fluorescence microscopy, single-shot incoherent full-color holographic microscopy with white light, and a palm-sized multidimensional incoherent hologram recorder have been developed using multidimensional IDH systems. Schematics and experimental results obtained using IDH techniques, incoherent holographic microscopy systems, and compact IDH systems are introduced.
{"title":"Review of Incoherent Digital Holography: Applications to Multidimensional Incoherent Digital Holographic Microscopy and Palm-Sized Digital Holographic Recorder—Holosensor","authors":"T. Tahara","doi":"10.3389/fphot.2021.829139","DOIUrl":"https://doi.org/10.3389/fphot.2021.829139","url":null,"abstract":"We review advancements in incoherent digital holography (IDH) with an image sensor and its applications to multidimensional microscopy and a palm-sized hologram recorder termed “holosensor”. There are two types of representative IDH technique: IDH with a structured illumination and a single photodetector termed optical scanning holography and self-interference IDH. The latter IDH is a technique to obtain an incoherent digital hologram by modulating an incoherent light wave between an object and an image sensor. Multidimensional information such as three-dimensional space and wavelengths is simultaneously recorded without changing optical filters by introducing interferometric techniques invented in laser holography. Applications to high-speed color-multiplexed holographic fluorescence microscopy, single-shot incoherent full-color holographic microscopy with white light, and a palm-sized multidimensional incoherent hologram recorder have been developed using multidimensional IDH systems. Schematics and experimental results obtained using IDH techniques, incoherent holographic microscopy systems, and compact IDH systems are introduced.","PeriodicalId":73099,"journal":{"name":"Frontiers in photonics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46416010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-31DOI: 10.3389/fphot.2022.937622
Bo-Han Chen, Jiansun Su, Jhan-Yu Guo, Kai Chen, S. Chu, Hsuan-Hao Lu, Chih-Hsuan Lu, Shang-Da Yang
We propose a new architecture, double-pass multiple-plate continuum (DPMPC), for nonlinear pulse compression. In addition to having a smaller footprint, a double-pass configuration is designed to achieve substantial bandwidth broadening without incurring noticeable higher-order dispersion, thus improving the temporal contrast over those of the traditional single-pass geometry when only the quadratic spectral phase can be compensated. In our proof-of-concept experiment, 187 μJ, 190-fs Yb-based laser pulse is compressed to 20 fs with high throughput (75%), high Strehl ratio (0.76), and excellent beam homogeneity by using DPMPC. The subsequently generated octave-spanning spectrum exhibits a significantly raised blue tail compared with that driven by pulses from a single-pass counterpart.
{"title":"Double-Pass Multiple-Plate Continuum for High-Temporal-Contrast Nonlinear Pulse Compression","authors":"Bo-Han Chen, Jiansun Su, Jhan-Yu Guo, Kai Chen, S. Chu, Hsuan-Hao Lu, Chih-Hsuan Lu, Shang-Da Yang","doi":"10.3389/fphot.2022.937622","DOIUrl":"https://doi.org/10.3389/fphot.2022.937622","url":null,"abstract":"We propose a new architecture, double-pass multiple-plate continuum (DPMPC), for nonlinear pulse compression. In addition to having a smaller footprint, a double-pass configuration is designed to achieve substantial bandwidth broadening without incurring noticeable higher-order dispersion, thus improving the temporal contrast over those of the traditional single-pass geometry when only the quadratic spectral phase can be compensated. In our proof-of-concept experiment, 187 μJ, 190-fs Yb-based laser pulse is compressed to 20 fs with high throughput (75%), high Strehl ratio (0.76), and excellent beam homogeneity by using DPMPC. The subsequently generated octave-spanning spectrum exhibits a significantly raised blue tail compared with that driven by pulses from a single-pass counterpart.","PeriodicalId":73099,"journal":{"name":"Frontiers in photonics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47437407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-19DOI: 10.3389/fphot.2021.825610
Nan-Nan Li, Chun Chen, Byoungho Lee, Di Wang, Qiong‐Hua Wang
Holography has emerged as one of the most attractive three-dimensional display technologies. With the technological development of computer science and coherent light source, the computer-generated holography has been applied in many fields. However, the speckle noise of the holographic reconstructed image seriously affects the viewing experience. In this paper, the cause of speckle noise generation in holographic display is introduced. Then, discussions about the speckle noise suppression methods are provided. The discussions are categorized into iterative and non-iterative approaches. Besides, we also introduce other speckle noise suppression techniques which are proposed from the perspective of light coherence, human visual system and optical system. Finally, the prospects of different types of approaches are summarized.
{"title":"Speckle Noise Suppression Algorithm of Holographic Display Based on Spatial Light Modulator (Invited)","authors":"Nan-Nan Li, Chun Chen, Byoungho Lee, Di Wang, Qiong‐Hua Wang","doi":"10.3389/fphot.2021.825610","DOIUrl":"https://doi.org/10.3389/fphot.2021.825610","url":null,"abstract":"Holography has emerged as one of the most attractive three-dimensional display technologies. With the technological development of computer science and coherent light source, the computer-generated holography has been applied in many fields. However, the speckle noise of the holographic reconstructed image seriously affects the viewing experience. In this paper, the cause of speckle noise generation in holographic display is introduced. Then, discussions about the speckle noise suppression methods are provided. The discussions are categorized into iterative and non-iterative approaches. Besides, we also introduce other speckle noise suppression techniques which are proposed from the perspective of light coherence, human visual system and optical system. Finally, the prospects of different types of approaches are summarized.","PeriodicalId":73099,"journal":{"name":"Frontiers in photonics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46837552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Visual cryptography (VC) is developed to be a promising approach to encoding secret information using pixel expansion rules. The useful information can be directly rendered based on human vision without the usage of decryption algorithms. However, many VC schemes cannot withstand occlusion attacks. In this paper, a new VC scheme is proposed using binary amplitude-only holograms (AOHs) generated by a modified Gerchberg-Saxton algorithm (MGSA). During the encryption, a secret image is divided into a group of unrecognizable and mutually-unrelated shares, and then the generated shares are further converted to binary AOHs using the MGSA. During image extraction, binary AOHs are logically superimposed to form a stacked hologram, and then the secret image can be extracted from the stacked hologram. Different from conventional VC schemes, the proposed VC scheme converts a secret image into binary AOHs. Due to the redundancy of the generated binary AOHs, the proposed method is numerically and experimentally verified to be feasible and effective, and possesses high robustness against occlusion attacks.
{"title":"Visual Cryptography Using Binary Amplitude-Only Holograms [Invited]","authors":"Lina Zhou, Yin Xiao, Zilan Pan, Yonggui Cao, Wen Chen","doi":"10.3389/fphot.2021.821304","DOIUrl":"https://doi.org/10.3389/fphot.2021.821304","url":null,"abstract":"Visual cryptography (VC) is developed to be a promising approach to encoding secret information using pixel expansion rules. The useful information can be directly rendered based on human vision without the usage of decryption algorithms. However, many VC schemes cannot withstand occlusion attacks. In this paper, a new VC scheme is proposed using binary amplitude-only holograms (AOHs) generated by a modified Gerchberg-Saxton algorithm (MGSA). During the encryption, a secret image is divided into a group of unrecognizable and mutually-unrelated shares, and then the generated shares are further converted to binary AOHs using the MGSA. During image extraction, binary AOHs are logically superimposed to form a stacked hologram, and then the secret image can be extracted from the stacked hologram. Different from conventional VC schemes, the proposed VC scheme converts a secret image into binary AOHs. Due to the redundancy of the generated binary AOHs, the proposed method is numerically and experimentally verified to be feasible and effective, and possesses high robustness against occlusion attacks.","PeriodicalId":73099,"journal":{"name":"Frontiers in photonics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47050114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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