Longlong Wu, Shinjae Yoo, Yong S. Chu, Xiaojing Huang, Ian K. Robinson
Ptychography, as a powerful lensless imaging method, has become a popular member of the coherent diffractive imaging family over decades of development. The ability to utilize low-dose X-rays and/or fast scans offers a big advantage in a ptychographic measurement (for example, when measuring radiation-sensitive samples), but results in low-photon statistics, making the subsequent phase retrieval challenging. Here, we demonstrate a dose-efficient automatic differentiation framework for ptychographic reconstruction (DAP) at low-photon statistics and low overlap ratio. As no reciprocal space constraint is required in this DAP framework, the framework, based on various forward models, shows superior performance under these conditions. It effectively suppresses potential artifacts in the reconstructed images, especially for the inherent periodic artifact in a raster scan. We validate the effectiveness and robustness of this method using both simulated and measured datasets.
层析成像是一种功能强大的无透镜成像方法，经过几十年的发展，已成为相干衍射成像家族中的热门成员。利用低剂量 X 射线和/或快速扫描的能力为分层成像测量提供了巨大优势（例如，在测量对辐射敏感的样品时），但会导致低光子统计，使后续的相位检索具有挑战性。在此，我们展示了一种在低光子统计量和低重叠率条件下的高剂量自动分辨框架（DAP）。由于该 DAP 框架不需要倒易空间约束，因此基于各种前向模型的该框架在这些条件下表现出卓越的性能。它能有效抑制重建图像中的潜在伪影，尤其是光栅扫描中固有的周期性伪影。我们利用模拟和测量数据集验证了这种方法的有效性和稳健性。
{"title":"Dose-efficient automatic differentiation for ptychographic reconstruction","authors":"Longlong Wu, Shinjae Yoo, Yong S. Chu, Xiaojing Huang, Ian K. Robinson","doi":"10.1364/optica.522380","DOIUrl":"https://doi.org/10.1364/optica.522380","url":null,"abstract":"Ptychography, as a powerful lensless imaging method, has become a popular member of the coherent diffractive imaging family over decades of development. The ability to utilize low-dose X-rays and/or fast scans offers a big advantage in a ptychographic measurement (for example, when measuring radiation-sensitive samples), but results in low-photon statistics, making the subsequent phase retrieval challenging. Here, we demonstrate a dose-efficient automatic differentiation framework for ptychographic reconstruction (DAP) at low-photon statistics and low overlap ratio. As no reciprocal space constraint is required in this DAP framework, the framework, based on various forward models, shows superior performance under these conditions. It effectively suppresses potential artifacts in the reconstructed images, especially for the inherent periodic artifact in a raster scan. We validate the effectiveness and robustness of this method using both simulated and measured datasets.","PeriodicalId":19515,"journal":{"name":"Optica","volume":"147 1","pages":""},"PeriodicalIF":10.4,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141867313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yusef Farah, Gabe Murray, Jeff Field, Maxine Varughese, Lang Wang, Olivier Pinaud, Randy Bartels
Third harmonic generation (THG) provides a valuable, label-free approach to imaging biological systems. To date, THG microscopy has been performed using point-scanning methods that rely on intensity measurements lacking phase information of the complex field. We report the first demonstration, to the best of our knowledge, of THG holographic microscopy and the reconstruction of the complex THG signal field with spatial synthetic aperture imaging. Phase distortions arising from measurement-to-measurement fluctuations and imaging components cause optical aberrations in the reconstructed THG field. We have developed an aberration-correction algorithm that estimates and corrects these phase distortions to reconstruct the spatial synthetic aperture THG field without optical aberrations.
{"title":"Synthetic spatial aperture holographic third harmonic generation microscopy","authors":"Yusef Farah, Gabe Murray, Jeff Field, Maxine Varughese, Lang Wang, Olivier Pinaud, Randy Bartels","doi":"10.1364/optica.521088","DOIUrl":"https://doi.org/10.1364/optica.521088","url":null,"abstract":"Third harmonic generation (THG) provides a valuable, label-free approach to imaging biological systems. To date, THG microscopy has been performed using point-scanning methods that rely on intensity measurements lacking phase information of the complex field. We report the first demonstration, to the best of our knowledge, of THG holographic microscopy and the reconstruction of the complex THG signal field with spatial synthetic aperture imaging. Phase distortions arising from measurement-to-measurement fluctuations and imaging components cause optical aberrations in the reconstructed THG field. We have developed an aberration-correction algorithm that estimates and corrects these phase distortions to reconstruct the spatial synthetic aperture THG field without optical aberrations.","PeriodicalId":19515,"journal":{"name":"Optica","volume":"209 1","pages":""},"PeriodicalIF":10.4,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141867312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rui Ma, Ke Hai Luo, Sushil Pokharel, Zhao Wang, Olga Korotkova, Jing Song He, Wei Li Zhang, Dian Yuan Fan, Anderson S. L. Gomes, and Jun Liu
Characterizing the orbital-angular-momentum (OAM) modes is critically important for OAM-encoded data transfer. However, traditional characterizing approaches rely on either complex and precise experimental configurations or complicated prior information processing. In these scenarios, the correlation features of OAM-dependent speckles from the scattering effect have received little attention. Here, we investigate the cross-correlation characteristics of the OAM speckles resulting from a scattering medium and propose an appealing alternative for spatial mode sorting and demultiplexing based on the OAM-dependent speckles. We demonstrate theoretically and experimentally that the cross-correlation operation between two different OAM-dependent speckles can uniformly derive an annulus pattern, whose dimension is determined by the absolute topological charge difference value between the two corresponding OAM modes. Based on this mechanism, the original coherent OAM modes can be easily sorted by implementing the cross-correlation operation between incoherently measured OAM-dependent speckles. To fully capitalize on the orthogonal feature of the OAM-dependent speckles, we also construct OAM mode demultiplexing experiments using a ground glass diffuser, where both 8-bit grayscale and 24-bit RGB OAM-encoded data demultiplexing are successfully demonstrated with superior error rates. Results show that the OAM-dependent speckles, previously treated as a nuisance for practical applications, can be surprisingly utilized as a competitive candidate for OAM mode sorting and demultiplexing, thus opening new directions in optical communication and information processing.
{"title":"Orbital-angular-momentum-dependent speckles for spatial mode sorting and demultiplexing","authors":"Rui Ma, Ke Hai Luo, Sushil Pokharel, Zhao Wang, Olga Korotkova, Jing Song He, Wei Li Zhang, Dian Yuan Fan, Anderson S. L. Gomes, and Jun Liu","doi":"10.1364/optica.523846","DOIUrl":"https://doi.org/10.1364/optica.523846","url":null,"abstract":"Characterizing the orbital-angular-momentum (OAM) modes is critically important for OAM-encoded data transfer. However, traditional characterizing approaches rely on either complex and precise experimental configurations or complicated prior information processing. In these scenarios, the correlation features of OAM-dependent speckles from the scattering effect have received little attention. Here, we investigate the cross-correlation characteristics of the OAM speckles resulting from a scattering medium and propose an appealing alternative for spatial mode sorting and demultiplexing based on the OAM-dependent speckles. We demonstrate theoretically and experimentally that the cross-correlation operation between two different OAM-dependent speckles can uniformly derive an annulus pattern, whose dimension is determined by the absolute topological charge difference value between the two corresponding OAM modes. Based on this mechanism, the original coherent OAM modes can be easily sorted by implementing the cross-correlation operation between incoherently measured OAM-dependent speckles. To fully capitalize on the orthogonal feature of the OAM-dependent speckles, we also construct OAM mode demultiplexing experiments using a ground glass diffuser, where both 8-bit grayscale and 24-bit RGB OAM-encoded data demultiplexing are successfully demonstrated with superior error rates. Results show that the OAM-dependent speckles, previously treated as a nuisance for practical applications, can be surprisingly utilized as a competitive candidate for OAM mode sorting and demultiplexing, thus opening new directions in optical communication and information processing.","PeriodicalId":19515,"journal":{"name":"Optica","volume":"142 1","pages":""},"PeriodicalIF":10.4,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140637642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Partridge, P. Wolfson, J. Jiang, L. Massimi, A. Astolfo, N. Djurabekova, S. Savvidis, C. J. Maughan Jones, C. K. Hagen, E. Millard, W. Shorrock, R. M. Waltham, I. G. Haig, D. Bate, K. M. A. Ho, H. Mc Bain, A. Wilson, A. Hogan, H. Delaney, A. Liyadipita, A. P. Levine, K. Dawas, B. Mohammadi, Y. A. Qureshi, M. D. Chouhan, S. A. Taylor, M. Mughal, P. R. T. Munro, M. Endrizzi, M. Novelli, et al.
With histopathology results typically taking several days, the ability to stage tumors during interventions could provide a step change in various cancer interventions. X-ray technology has advanced significantly in recent years with the introduction of phase-based imaging methods. These have been adapted for use in standard labs rather than specialized facilities such as synchrotrons, and approaches that enable fast 3D scans with conventional x-ray sources have been developed. This opens the possibility to produce 3D images with enhanced soft tissue contrast at a level of detail comparable to histopathology, in times sufficiently short to be compatible with use during surgical interventions. In this paper we discuss the application of one such approach to human esophagi obtained from esophagectomy interventions. We demonstrate that the image quality is sufficiently high to enable tumor rm T staging based on the x-ray datasets alone. Alongside detection of involved margins with potentially life-saving implications, staging tumors intra-operatively has the potential to change patient pathways, facilitating optimization of therapeutic interventions during the procedure itself. Besides a prospective intra-operative use, the availability of high-quality 3D images of entire esophageal tumors can support histopathological characterization, from enabling “right slice first time” approaches to understanding the histopathology in the full 3D context of the surrounding tumor environment.
由于组织病理学检查结果通常需要数天时间，因此在干预过程中对肿瘤进行分期的能力可为各种癌症干预措施带来重大变革。近年来，随着相位成像方法的引入，X 射线技术有了长足的进步。这些方法已适用于标准实验室，而不是同步加速器等专业设施，而且还开发出了利用传统 X 射线源进行快速三维扫描的方法。这为生成具有增强软组织对比度的三维图像提供了可能性，其详细程度可与组织病理学相媲美，而且扫描时间短，可在外科手术中使用。在本文中，我们讨论了将这种方法应用于食管切除术中获取的人体食管。我们证明，这种方法的图像质量很高，仅根据 X 射线数据集就能对肿瘤进行分期。术中对肿瘤进行分期，除了能检测到有可能挽救生命的受累边缘外，还有可能改变患者的治疗路径，促进手术过程中治疗干预措施的优化。除了术中的前瞻性应用外，整个食管肿瘤的高质量三维图像还能支持组织病理学特征描述，从实现 "首次正确切片 "的方法到在肿瘤周围环境的完整三维背景下理解组织病理学。
{"title":"T staging esophageal tumors with x rays","authors":"T. Partridge, P. Wolfson, J. Jiang, L. Massimi, A. Astolfo, N. Djurabekova, S. Savvidis, C. J. Maughan Jones, C. K. Hagen, E. Millard, W. Shorrock, R. M. Waltham, I. G. Haig, D. Bate, K. M. A. Ho, H. Mc Bain, A. Wilson, A. Hogan, H. Delaney, A. Liyadipita, A. P. Levine, K. Dawas, B. Mohammadi, Y. A. Qureshi, M. D. Chouhan, S. A. Taylor, M. Mughal, P. R. T. Munro, M. Endrizzi, M. Novelli, et al.","doi":"10.1364/optica.501948","DOIUrl":"https://doi.org/10.1364/optica.501948","url":null,"abstract":"With histopathology results typically taking several days, the ability to stage tumors during interventions could provide a step change in various cancer interventions. X-ray technology has advanced significantly in recent years with the introduction of phase-based imaging methods. These have been adapted for use in standard labs rather than specialized facilities such as synchrotrons, and approaches that enable fast 3D scans with conventional x-ray sources have been developed. This opens the possibility to produce 3D images with enhanced soft tissue contrast at a level of detail comparable to histopathology, in times sufficiently short to be compatible with use during surgical interventions. In this paper we discuss the application of one such approach to human esophagi obtained from esophagectomy interventions. We demonstrate that the image quality is sufficiently high to enable tumor <span><span>rm T</span><script type=\"math/tex\">rm T</script></span> staging based on the x-ray datasets alone. Alongside detection of involved margins with potentially life-saving implications, staging tumors intra-operatively has the potential to change patient pathways, facilitating optimization of therapeutic interventions during the procedure itself. Besides a prospective intra-operative use, the availability of high-quality 3D images of entire esophageal tumors can support histopathological characterization, from enabling “right slice first time” approaches to understanding the histopathology in the full 3D context of the surrounding tumor environment.","PeriodicalId":19515,"journal":{"name":"Optica","volume":"30 1","pages":""},"PeriodicalIF":10.4,"publicationDate":"2024-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140621604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. V. Loginov, D. B. Boltje, M. N. F. Hensgens, J. P. Hoogenboom, and E. B. van der Wee
In volume fluorescence microscopy, refractive index matching is essential to minimize aberrations. There are, however, common imaging scenarios where a refractive index mismatch (RIM) between immersion and a sample medium cannot be avoided. This RIM leads to an axial deformation in the acquired image data. Over the years, different axial scaling factors have been proposed to correct for this deformation. While some reports have suggested a depth-dependent axial deformation, so far none of the scaling theories has accounted for a depth-dependent, non-linear scaling. Here, we derive an analytical theory based on determining the leading constructive interference band in the objective lens pupil under RIM. We then use this to calculate a depth-dependent re-scaling factor as a function of the numerical aperture (NA), the refractive indices {n_1} and {n_2}, and the wavelength lambda. We compare our theoretical results with wave-optics calculations and experimental results obtained using a measurement scheme for different values of NA and RIM. As a benchmark, we recorded multiple datasets in different RIM conditions, and corrected these using our depth-dependent axial scaling theory. Finally, we present an online web applet that visualizes the depth-dependent axial re-scaling for specific optical setups. In addition, we provide software that will help microscopists to correctly re-scale the axial dimension in their imaging data when working under RIM.
在体视荧光显微镜中，折射率匹配对于减少像差至关重要。然而，在一些常见的成像场景中，无法避免浸入液和样品介质之间的折射率失配（RIM）。这种折射率失配会导致获取的图像数据出现轴向变形。多年来，人们提出了不同的轴向缩放因子来校正这种变形。虽然有些报告提出了与深度相关的轴向变形，但迄今为止，还没有一种缩放理论能够解释与深度相关的非线性缩放。在此，我们基于确定 RIM 下物镜瞳孔中的前导建设性干涉带，推导出一种分析理论。然后，我们用它来计算依赖于深度的再缩放因子，该因子是数值孔径 (NA)、折射率 {n_1}{n_1} 和 {n_2}{n_2} 以及波长 lambdalambda 的函数。我们将理论结果与波光学计算结果以及使用测量方案获得的不同 NA 值和 RIM 值的实验结果进行了比较。作为基准，我们记录了不同 RIM 条件下的多个数据集，并使用我们的深度依赖轴向缩放理论对其进行了校正。最后，我们提供了一个在线网络小程序，可视化特定光学设置下的深度依赖性轴向再缩放。此外，我们还提供了一款软件，帮助显微镜学家在 RIM 条件下工作时正确地重新缩放成像数据的轴向尺寸。
{"title":"Depth-dependent scaling of axial distances in light microscopy","authors":"S. V. Loginov, D. B. Boltje, M. N. F. Hensgens, J. P. Hoogenboom, and E. B. van der Wee","doi":"10.1364/optica.520595","DOIUrl":"https://doi.org/10.1364/optica.520595","url":null,"abstract":"In volume fluorescence microscopy, refractive index matching is essential to minimize aberrations. There are, however, common imaging scenarios where a refractive index mismatch (RIM) between immersion and a sample medium cannot be avoided. This RIM leads to an axial deformation in the acquired image data. Over the years, different axial scaling factors have been proposed to correct for this deformation. While some reports have suggested a <i>depth-dependent</i> axial deformation, so far none of the scaling theories has accounted for a depth-dependent, non-linear scaling. Here, we derive an analytical theory based on determining the leading constructive interference band in the objective lens pupil under RIM. We then use this to calculate a depth-dependent re-scaling factor as a function of the numerical aperture (NA), the refractive indices <span><span>{n_1}</span><script type=\"math/tex\">{n_1}</script></span> and <span><span>{n_2}</span><script type=\"math/tex\">{n_2}</script></span>, and the wavelength <span><span>lambda</span><script type=\"math/tex\">lambda</script></span>. We compare our theoretical results with wave-optics calculations and experimental results obtained using a measurement scheme for different values of NA and RIM. As a benchmark, we recorded multiple datasets in different RIM conditions, and corrected these using our depth-dependent axial scaling theory. Finally, we present an online web applet that visualizes the depth-dependent axial re-scaling for specific optical setups. In addition, we provide software that will help microscopists to correctly re-scale the axial dimension in their imaging data when working under RIM.","PeriodicalId":19515,"journal":{"name":"Optica","volume":"20 1","pages":""},"PeriodicalIF":10.4,"publicationDate":"2024-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140621516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Characterizing the indistinguishability of photons is a key task in quantum photonics, underpinning the tuning and stabilization of the photon sources and thereby increasing the accuracy of quantum operations. The protocols for measuring the degree of indistinguishability conventionally require photon-coincidence measurements at several different time or phase delays, which is a fundamental bottleneck towards fast measurements and real-time monitoring of indistinguishability. Here, we develop a static dielectric metasurface grating without any reconfigurable elements that realizes a tailored multiport transformation in the free-space configuration without the need for phase locking and enables single-shot characterization of the indistinguishability between two photons in multiple degrees of freedom including time, spectrum, spatial modes, and polarization. Topology optimization is employed to design a silicon metasurface with polarization independence, high transmission, and high tolerance to measurement noise. We fabricate the metasurface and experimentally quantify the indistinguishability of photons in the time domain with fidelity over 98.4%. We anticipate that the developed framework based on ultrathin metasurfaces can be further extended for multi-photon states and additional degrees of freedom associated with spatial modalities.
{"title":"Single-shot characterization of photon indistinguishability with dielectric metasurfaces","authors":"Jihua Zhang, Jinyong Ma, Neuton Li, Shaun Lung, Andrey A. Sukhorukov","doi":"10.1364/optica.516064","DOIUrl":"https://doi.org/10.1364/optica.516064","url":null,"abstract":"Characterizing the indistinguishability of photons is a key task in quantum photonics, underpinning the tuning and stabilization of the photon sources and thereby increasing the accuracy of quantum operations. The protocols for measuring the degree of indistinguishability conventionally require photon-coincidence measurements at several different time or phase delays, which is a fundamental bottleneck towards fast measurements and real-time monitoring of indistinguishability. Here, we develop a static dielectric metasurface grating without any reconfigurable elements that realizes a tailored multiport transformation in the free-space configuration without the need for phase locking and enables single-shot characterization of the indistinguishability between two photons in multiple degrees of freedom including time, spectrum, spatial modes, and polarization. Topology optimization is employed to design a silicon metasurface with polarization independence, high transmission, and high tolerance to measurement noise. We fabricate the metasurface and experimentally quantify the indistinguishability of photons in the time domain with fidelity over 98.4%. We anticipate that the developed framework based on ultrathin metasurfaces can be further extended for multi-photon states and additional degrees of freedom associated with spatial modalities.","PeriodicalId":19515,"journal":{"name":"Optica","volume":"13 1","pages":""},"PeriodicalIF":10.4,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141867314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
William Loh, Dodd Gray, Reed Irion, Owen May, Connor Belanger, Jason Plant, Paul W. Juodawlkis, and Siva Yegnanarayanan
Low phase noise microwave oscillators are at the center of a multitude of applications that span the gamut of photonics and electronics. Within this space, optically derived approaches to microwave frequency synthesis are particularly compelling owing to their unique combination of ultrawideband frequency access and the potential for resiliency to temperature and environmental perturbation via common-mode noise rejection. We demonstrate here an optical frequency divider that uses the 30 terahertz frequency gap between two stimulated Brillouin scattering (SBS) lasers as the basis for frequency division. The resulting microwave signal, centered at 10 GHz frequency, exhibits exceptionally low phase noise levels of −95dBc/Hz and −110dBc/Hz at 10 Hz and 100 Hz frequency offset, respectively. Moreover, the two SBS lasers, generated from a common fiber resonator, exhibit a high degree of correlated noise cancellation in their frequency difference. We measure 16.1 dB of noise rejection against intentionally applied vibrations, thus showcasing a promising pathway towards portable and robust ultralow noise photonic-microwave synthesis.
低相位噪声微波振荡器是光子学和电子学领域众多应用的核心。在这一领域，微波频率合成的光学衍生方法尤为引人注目，因为它们将超宽带频率接入和通过共模噪声抑制来抵御温度和环境扰动的潜力独特地结合在一起。我们在此展示了一种光学分频器，它利用两个受激布里渊散射（SBS）激光器之间的 30 太赫兹频率间隙作为分频的基础。由此产生的微波信号以 10 GHz 频率为中心，在 10 Hz 和 100 Hz 频率偏移时分别表现出-95dBc/Hz{-}{95};{rm dBc/Hz}和-110dBc/Hz{-}{110};{rm dBc/Hz}的超低相位噪声水平。此外，这两个 SBS 激光器由一个共用光纤谐振器产生，在它们的频率差中表现出高度的相关噪声抵消。我们测得 16.1 dB 的噪声抑制能力可抵御有意施加的振动，从而为实现便携式、坚固耐用的超低噪声光子微波合成提供了一条大有可为的途径。
{"title":"Ultralow noise microwave synthesis via difference frequency division of a Brillouin resonator","authors":"William Loh, Dodd Gray, Reed Irion, Owen May, Connor Belanger, Jason Plant, Paul W. Juodawlkis, and Siva Yegnanarayanan","doi":"10.1364/optica.515321","DOIUrl":"https://doi.org/10.1364/optica.515321","url":null,"abstract":"Low phase noise microwave oscillators are at the center of a multitude of applications that span the gamut of photonics and electronics. Within this space, optically derived approaches to microwave frequency synthesis are particularly compelling owing to their unique combination of ultrawideband frequency access and the potential for resiliency to temperature and environmental perturbation via common-mode noise rejection. We demonstrate here an optical frequency divider that uses the 30 terahertz frequency gap between two stimulated Brillouin scattering (SBS) lasers as the basis for frequency division. The resulting microwave signal, centered at 10 GHz frequency, exhibits exceptionally low phase noise levels of <span><span style=\"color: inherit;\"><span><span><span style=\"margin-left: 0.267em; margin-right: 0.267em;\">−</span></span><span><span>95</span></span><span style=\"width: 0.278em; height: 0em;\"></span><span><span>d</span><span>B</span><span>c</span><span><span style=\"margin-left: 0.111em; margin-right: 0.111em;\">/</span></span><span>H</span><span>z</span></span></span></span><script type=\"math/tex\">{-}{95};{rm dBc/Hz}</script></span> and <span><span style=\"color: inherit;\"><span><span><span style=\"margin-left: 0.267em; margin-right: 0.267em;\">−</span></span><span><span>110</span></span><span style=\"width: 0.278em; height: 0em;\"></span><span><span>d</span><span>B</span><span>c</span><span><span style=\"margin-left: 0.111em; margin-right: 0.111em;\">/</span></span><span>H</span><span>z</span></span></span></span><script type=\"math/tex\">{-}{110};{rm dBc/Hz}</script></span> at 10 Hz and 100 Hz frequency offset, respectively. Moreover, the two SBS lasers, generated from a common fiber resonator, exhibit a high degree of correlated noise cancellation in their frequency difference. We measure 16.1 dB of noise rejection against intentionally applied vibrations, thus showcasing a promising pathway towards portable and robust ultralow noise photonic-microwave synthesis.","PeriodicalId":19515,"journal":{"name":"Optica","volume":"47 1","pages":""},"PeriodicalIF":10.4,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140538121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
X-ray phase contrast imaging holds great promise for improving the visibility of light-element materials such as soft tissues and tumors. The single-mask differential phase contrast imaging method stands out as a simple and effective approach to yield differential phase contrast. In this work, we introduce a model for a single-mask phase imaging system based on the transport-of-intensity equation. Our model provides an accessible understanding of signal and contrast formation in single-mask x-ray phase imaging, offering a clear perspective on the image formation process, for example, the origin of alternate bright and dark fringes in phase contrast intensity images. Aided by our model, we present an efficient retrieval method that yields differential phase contrast imagery in a single acquisition step. Our model gives insight into the contrast generation and its dependence on the system geometry and imaging parameters in both the initial intensity image as well as retrieved images. The model validity as well as the proposed retrieval method are demonstrated via both experimental results on a system developed in house as well as Monte Carlo simulations. In conclusion, our work not only provides a model for an intuitive visualization of image formation but also offers a method to optimize differential phase imaging setups, holding tremendous promise for advancing medical diagnostics and other applications.
X 射线相衬成像技术在提高软组织和肿瘤等光元素材料的可见度方面大有可为。单掩膜差分相位对比成像法是产生差分相位对比的一种简单而有效的方法。在这项工作中，我们介绍了基于强度传输方程的单掩膜相位成像系统模型。我们的模型提供了对单掩膜 X 射线相位成像中信号和对比度形成的理解，为图像形成过程提供了一个清晰的视角，例如，相位对比强度图像中交替出现的明暗条纹的起源。在模型的帮助下，我们提出了一种高效的检索方法，只需一个采集步骤就能获得不同的相位对比图像。我们的模型深入揭示了对比度的产生及其与初始强度图像和检索图像中的系统几何和成像参数的关系。模型的有效性和所提出的检索方法通过在内部开发的系统上的实验结果和蒙特卡罗模拟得到了证明。总之，我们的工作不仅为图像形成的直观可视化提供了一个模型，还为优化差分相位成像设置提供了一种方法，为推进医疗诊断和其他应用带来了巨大的希望。
{"title":"Transport-of-intensity model for single-mask x-ray differential phase contrast imaging","authors":"Jingcheng Yuan and Mini Das","doi":"10.1364/optica.510537","DOIUrl":"https://doi.org/10.1364/optica.510537","url":null,"abstract":"X-ray phase contrast imaging holds great promise for improving the visibility of light-element materials such as soft tissues and tumors. The single-mask differential phase contrast imaging method stands out as a simple and effective approach to yield differential phase contrast. In this work, we introduce a model for a single-mask phase imaging system based on the transport-of-intensity equation. Our model provides an accessible understanding of signal and contrast formation in single-mask x-ray phase imaging, offering a clear perspective on the image formation process, for example, the origin of alternate bright and dark fringes in phase contrast intensity images. Aided by our model, we present an efficient retrieval method that yields differential phase contrast imagery in a single acquisition step. Our model gives insight into the contrast generation and its dependence on the system geometry and imaging parameters in both the initial intensity image as well as retrieved images. The model validity as well as the proposed retrieval method are demonstrated via both experimental results on a system developed in house as well as Monte Carlo simulations. In conclusion, our work not only provides a model for an intuitive visualization of image formation but also offers a method to optimize differential phase imaging setups, holding tremendous promise for advancing medical diagnostics and other applications.","PeriodicalId":19515,"journal":{"name":"Optica","volume":"56 1","pages":""},"PeriodicalIF":10.4,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140352220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lukas Fürst, Adrian Kirchner, Alexander Eber, Florian Siegrist, Robert di Vora, and Birgitta Bernhardt
The highly energetic photons of ultraviolet light drive electronic and rovibronic transitions in all molecular species. This radiation is thus a prime tool for strongly selective spectroscopic fingerprinting and real-time environmental monitoring if broad spectral coverage, short acquisition times, and high spectral resolution are achieved–requirements that are in mutual competition in traditional applications. As an approach with intrinsic potency in all three aspects, here we introduce ultraviolet dual comb spectroscopy using two broadband ultraviolet frequency combs centered at 871 THz and covering a spectral bandwidth of 35.7 THz. Within a 100 µs acquisition time window, we obtain rotational state-resolved absorption spectra of formaldehyde, a prototype molecule with high relevance for laser spectroscopy and environmental sciences. To our knowledge, this is the first realization of broadband dual comb spectroscopy in the ultraviolet spectral region and a pioneering tool to allow for real-time monitoring of rovibronic transitions.
{"title":"Broadband near-ultraviolet dual comb spectroscopy","authors":"Lukas Fürst, Adrian Kirchner, Alexander Eber, Florian Siegrist, Robert di Vora, and Birgitta Bernhardt","doi":"10.1364/optica.516783","DOIUrl":"https://doi.org/10.1364/optica.516783","url":null,"abstract":"The highly energetic photons of ultraviolet light drive electronic and rovibronic transitions in all molecular species. This radiation is thus a prime tool for strongly selective spectroscopic fingerprinting and real-time environmental monitoring if broad spectral coverage, short acquisition times, and high spectral resolution are achieved–requirements that are in mutual competition in traditional applications. As an approach with intrinsic potency in all three aspects, here we introduce ultraviolet dual comb spectroscopy using two broadband ultraviolet frequency combs centered at 871 THz and covering a spectral bandwidth of 35.7 THz. Within a 100 µs acquisition time window, we obtain rotational state-resolved absorption spectra of formaldehyde, a prototype molecule with high relevance for laser spectroscopy and environmental sciences. To our knowledge, this is the first realization of broadband dual comb spectroscopy in the ultraviolet spectral region and a pioneering tool to allow for real-time monitoring of rovibronic transitions.","PeriodicalId":19515,"journal":{"name":"Optica","volume":"32 1","pages":""},"PeriodicalIF":10.4,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140343325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Theoretical bounds are commonly used to assess the limitations of photonic design. Here we introduce a more active way to use theoretical bounds, integrating them into part of the design process and identifying optimal system parameters that maximize the efficiency limit itself. As an example, we consider wide-field-of-view high-numerical-aperture metalenses, which can be used for high-resolution imaging in microscopy and endoscopy, but no existing design has achieved a high efficiency. By choosing aperture sizes to maximize an efficiency bound, setting the thickness according to a thickness bound, and then performing inverse design, we come up with high-numerical-aperture (NA=0.9) metalens designs with, to our knowledge, record-high 98% transmission efficiency and 92% Strehl ratio across all incident angles within a 60° field of view, reaching the maximized bound. This maximizing-efficiency-limit approach applies to any multi-channel system and can help a wide range of optical devices reach their highest possible performance.
{"title":"High-efficiency high-numerical-aperture metalens designed by maximizing the efficiency limit","authors":"Shiyu Li, Ho-Chun Lin, and Chia Wei Hsu","doi":"10.1364/optica.514907","DOIUrl":"https://doi.org/10.1364/optica.514907","url":null,"abstract":"Theoretical bounds are commonly used to assess the limitations of photonic design. Here we introduce a more active way to use theoretical bounds, integrating them into part of the design process and identifying optimal system parameters that maximize the efficiency limit itself. As an example, we consider wide-field-of-view high-numerical-aperture metalenses, which can be used for high-resolution imaging in microscopy and endoscopy, but no existing design has achieved a high efficiency. By choosing aperture sizes to maximize an efficiency bound, setting the thickness according to a thickness bound, and then performing inverse design, we come up with high-numerical-aperture (<span><span style=\"color: inherit;\"><span><span><span>N</span><span>A</span></span><span style=\"margin-left: 0.333em; margin-right: 0.333em;\">=</span><span><span>0.9</span></span></span></span><script type=\"math/tex\">{rm NA} = {0.9}</script></span>) metalens designs with, to our knowledge, record-high 98% transmission efficiency and 92% Strehl ratio across all incident angles within a 60° field of view, reaching the maximized bound. This maximizing-efficiency-limit approach applies to any multi-channel system and can help a wide range of optical devices reach their highest possible performance.","PeriodicalId":19515,"journal":{"name":"Optica","volume":"45 1","pages":""},"PeriodicalIF":10.4,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140322032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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