Hippolyte Dupont, Matthieu Glasset, Pavel Loiko, Patrick Georges, Frédéric Druon
We report on the chaotic dynamics in a passively Q-switched 2.3-μm thulium laser operating on the 3H4 → 3H5 transition. The experiment exploits a Tm:LiYF4 crystal and various laser cavity configurations, involving an optional cascade laser on the 3F4 → 3H6 transition at 1.9 μm. The saturable absorber employed is Cr2+:ZnSe, which is exclusively saturated by the 2.3 μm laser. An analysis of the Q-switched dynamics shows a pronounced inclination of the laser operation toward the unstable and chaotic behavior. To understand the origins of this chaos, we monitor the population of the metastable 3F4 level via cascade laser operation at 1.9 μm, underlying this variable as an interesting parameter to survey chaotic instabilities.
{"title":"Chaotic dynamics in passively Q-switched Tm:LiYF4 laser operating at 2.3 μm on the 3H4 → 3H5 transition","authors":"Hippolyte Dupont, Matthieu Glasset, Pavel Loiko, Patrick Georges, Frédéric Druon","doi":"10.1063/5.0220220","DOIUrl":"https://doi.org/10.1063/5.0220220","url":null,"abstract":"We report on the chaotic dynamics in a passively Q-switched 2.3-μm thulium laser operating on the 3H4 → 3H5 transition. The experiment exploits a Tm:LiYF4 crystal and various laser cavity configurations, involving an optional cascade laser on the 3F4 → 3H6 transition at 1.9 μm. The saturable absorber employed is Cr2+:ZnSe, which is exclusively saturated by the 2.3 μm laser. An analysis of the Q-switched dynamics shows a pronounced inclination of the laser operation toward the unstable and chaotic behavior. To understand the origins of this chaos, we monitor the population of the metastable 3F4 level via cascade laser operation at 1.9 μm, underlying this variable as an interesting parameter to survey chaotic instabilities.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"3 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199457","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}
Wenhua Su, Dachao Zheng, Jiacheng Zhou, Qiushu Chen, Liwen Chen, Yuwei Yang, Yiyan Fei, Haijun Yao, Jiong Ma, Lan Mi
The precise determination of surgical margins is essential for the management of multifocal cutaneous cancers, including extramammary Paget’s disease. This study introduces a novel strategy for precise margin identification in such tumors, employing multichannel autofluorescence lifetime decay (MALD), fluorescence lifetime imaging microscopy (FLIM), and machine learning, including confidence learning algorithms. Using FLIM, 51 unstained frozen sections were analyzed, of which 13 (25%) sections, containing 5003 FLIM patches, were used for training the residual network model (ResNet–FLIM). The remaining 38 (75%) sections, including 16 918 patches, were retained for external validation. Application of confidence learning with deep learning reduced the reliance on extensive pathologist annotation. Refined labels obtained by ResNet–FLIM were then incorporated into a support vector machine (SVM) model, which utilized fiber-optic-based MALD data. Both models exhibited substantial agreement with the pathological assessments. Of the 35 MALD-measured tissue segments, six (17%) segments were selected as the training dataset, including 900 decay profiles. The remaining 29 segments (83%), including 2406 decay profiles, were reserved for external validation. The ResNet–FLIM model achieved 100% sensitivity and specificity. The SVM–MALD model demonstrated 94% sensitivity and 83% specificity. Notably, fiber-optic-MALD allows assessing 12 sites per patient and delivering predictions within 10 min. Variations in the necessary safe margin length were observed among patients, highlighting the necessity for patient-specific approaches to determine surgical margins. This innovative approach holds potential for wide clinical application, providing a rapid and accurate margin evaluation method that significantly reduces a pathologist’s workload and improves patient outcomes through personalized medicine.
{"title":"Rapid and precise multifocal cutaneous tumor margin assessment using fluorescence lifetime detection and machine learning","authors":"Wenhua Su, Dachao Zheng, Jiacheng Zhou, Qiushu Chen, Liwen Chen, Yuwei Yang, Yiyan Fei, Haijun Yao, Jiong Ma, Lan Mi","doi":"10.1063/5.0224181","DOIUrl":"https://doi.org/10.1063/5.0224181","url":null,"abstract":"The precise determination of surgical margins is essential for the management of multifocal cutaneous cancers, including extramammary Paget’s disease. This study introduces a novel strategy for precise margin identification in such tumors, employing multichannel autofluorescence lifetime decay (MALD), fluorescence lifetime imaging microscopy (FLIM), and machine learning, including confidence learning algorithms. Using FLIM, 51 unstained frozen sections were analyzed, of which 13 (25%) sections, containing 5003 FLIM patches, were used for training the residual network model (ResNet–FLIM). The remaining 38 (75%) sections, including 16 918 patches, were retained for external validation. Application of confidence learning with deep learning reduced the reliance on extensive pathologist annotation. Refined labels obtained by ResNet–FLIM were then incorporated into a support vector machine (SVM) model, which utilized fiber-optic-based MALD data. Both models exhibited substantial agreement with the pathological assessments. Of the 35 MALD-measured tissue segments, six (17%) segments were selected as the training dataset, including 900 decay profiles. The remaining 29 segments (83%), including 2406 decay profiles, were reserved for external validation. The ResNet–FLIM model achieved 100% sensitivity and specificity. The SVM–MALD model demonstrated 94% sensitivity and 83% specificity. Notably, fiber-optic-MALD allows assessing 12 sites per patient and delivering predictions within 10 min. Variations in the necessary safe margin length were observed among patients, highlighting the necessity for patient-specific approaches to determine surgical margins. This innovative approach holds potential for wide clinical application, providing a rapid and accurate margin evaluation method that significantly reduces a pathologist’s workload and improves patient outcomes through personalized medicine.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"72 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199455","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}
Hanjie Wang, Lin Zhao, Huiyue You, Huiling Wu, Qingliang Zhao, Xin Dong, Shengchuang Bai, Hongsen He, Jun Dong
Functional photoacoustic microscopy (PAM) requires laser sources with multiple wavelengths targeting abundant substances, where lipid and water are important components of living organisms. Here, we propose to use a single compact dual-wavelength passively Q-switched solid-state laser as the excitation source to directly achieve PA differentiation of water and lipid simultaneously. The main contribution of our work is to use the excitation difference under 1064- and 1176-nm lasers for mapping water and lipid in PAM, respectively. Meanwhile, the miniature structure (cavity size: ∼10 × 10 × 5.5 mm3) of the laser source is not only promising for portable applications but also benefits the PA-desired nanosecond (<2 ns) laser pulse establishment. Our technique is confirmed by efficient PA imaging of water and lipid in biological tissues at high spatial resolution and improved sensitivity. This laser provides a novel and low-cost imaging source for PAM to track changes in water and lipid distribution.
功能光声显微镜（PAM）需要针对丰富物质的多波长激光源，而脂质和水是生物体的重要组成部分。在此，我们建议使用单个紧凑型双波长被动 Q 开关固体激光器作为激发光源，直接同时实现水和脂质的 PA 分化。我们工作的主要贡献是利用 1064 和 1176 纳米激光下的激发差，分别绘制 PAM 中水和脂的分布图。同时，激光源的微型结构（腔体尺寸：∼10 × 10 × 5.5 mm3）不仅有利于便携式应用，还有利于 PA 所需的纳秒（<2 ns）激光脉冲建立。我们的技术得到了生物组织中水和脂质的高效 PA 成像的证实，空间分辨率高，灵敏度更高。这种激光为 PAM 跟踪水和脂质分布变化提供了一种新颖、低成本的成像源。
{"title":"Dual-wavelength, nanosecond, miniature Raman laser enables efficient photoacoustic differentiation of water and lipid","authors":"Hanjie Wang, Lin Zhao, Huiyue You, Huiling Wu, Qingliang Zhao, Xin Dong, Shengchuang Bai, Hongsen He, Jun Dong","doi":"10.1063/5.0216255","DOIUrl":"https://doi.org/10.1063/5.0216255","url":null,"abstract":"Functional photoacoustic microscopy (PAM) requires laser sources with multiple wavelengths targeting abundant substances, where lipid and water are important components of living organisms. Here, we propose to use a single compact dual-wavelength passively Q-switched solid-state laser as the excitation source to directly achieve PA differentiation of water and lipid simultaneously. The main contribution of our work is to use the excitation difference under 1064- and 1176-nm lasers for mapping water and lipid in PAM, respectively. Meanwhile, the miniature structure (cavity size: ∼10 × 10 × 5.5 mm3) of the laser source is not only promising for portable applications but also benefits the PA-desired nanosecond (&lt;2 ns) laser pulse establishment. Our technique is confirmed by efficient PA imaging of water and lipid in biological tissues at high spatial resolution and improved sensitivity. This laser provides a novel and low-cost imaging source for PAM to track changes in water and lipid distribution.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"50 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199459","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}
I. Ansari, G. F. Feutmba, J. P. George, H. Rijckaert, J. Beeckman, D. Van Thourhout
Piezoelectric optomechanical platforms provide a promising avenue for efficient signal transduction between microwave and optical domains. Lead zirconate titanate (PZT) thin film stands out as a compelling choice for building such a platform given its high piezoelectricity and optical transparency, enabling strong electro-optomechanical transduction. This work explores the application of such transduction to induce Fano resonance in a silicon photonics integrated circuit (PIC). Our methodology involves integrating a PZT thin film onto a silicon PIC and subsequently removing the SiO2 layer to suspend the silicon waveguide, allowing controlled mechanical vibrations. Fano resonances, characterized by their distinctive asymmetric line shape, were observed at frequencies up to 6.7 GHz with an extinction ratio of 21 dB. A high extinction ratio of 41 dB was achieved at the lower resonance frequency of 223 MHz. Our results demonstrate the potential of piezoelectric thin film integration for the generation of Fano resonances on passive photonic platforms such as Si, paving the way for highly sensitive, compact, and power-efficient devices relevant to a wide range of applications.
{"title":"Piezoelectrically driven Fano resonance in silicon photonics","authors":"I. Ansari, G. F. Feutmba, J. P. George, H. Rijckaert, J. Beeckman, D. Van Thourhout","doi":"10.1063/5.0207482","DOIUrl":"https://doi.org/10.1063/5.0207482","url":null,"abstract":"Piezoelectric optomechanical platforms provide a promising avenue for efficient signal transduction between microwave and optical domains. Lead zirconate titanate (PZT) thin film stands out as a compelling choice for building such a platform given its high piezoelectricity and optical transparency, enabling strong electro-optomechanical transduction. This work explores the application of such transduction to induce Fano resonance in a silicon photonics integrated circuit (PIC). Our methodology involves integrating a PZT thin film onto a silicon PIC and subsequently removing the SiO2 layer to suspend the silicon waveguide, allowing controlled mechanical vibrations. Fano resonances, characterized by their distinctive asymmetric line shape, were observed at frequencies up to 6.7 GHz with an extinction ratio of 21 dB. A high extinction ratio of 41 dB was achieved at the lower resonance frequency of 223 MHz. Our results demonstrate the potential of piezoelectric thin film integration for the generation of Fano resonances on passive photonic platforms such as Si, paving the way for highly sensitive, compact, and power-efficient devices relevant to a wide range of applications.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"35 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199458","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}
Fraser T. Watt, Vivek Muthurangu, Jennifer Steeden, Eleanor C. Mackle, Adrien E. Desjardins, Edward Z. Zhang, Paul C. Beard, Erwin J. Alles
Optical ultrasound (OpUS) imaging is an ultrasound modality that utilizes fiber-optic ultrasound sources and detectors to perform pulse-echo ultrasound imaging. These probes can be constructed entirely from glass optical fibers and plastic components, and as such, these devices have been predicted to be compatible with computed tomography (CT) and magnetic resonance imaging (MRI), modalities that use intense electromagnetic fields for imaging. However, to date, this compatibility has not been demonstrated. In this work, a free-hand OpUS imaging system was developed specifically to investigate the compatibility of OpUS systems with CT and MRI imaging systems. The OpUS imaging platform discussed in this work was used to perform real-time OpUS imaging under (separately) concurrent CT and MRI. CT and MRI imaging of the OpUS probe was used to determine if the probe itself would induce artifacts in the CT and MRI imaging, and ultrasound resolution targets and background measurements were used to assess any impact of CT and MRI on the OpUS signal fidelity. These measurements demonstrate that there was negligible interaction between the OpUS system and both the CT and MRI systems, and to further demonstrate this capability, concurrent OpUS-CT and OpUS-MRI imaging was conducted of a tissue-mimicking phantom and a dynamic motion phantom. This work presents a comprehensive demonstration of an OpUS imaging system operating alongside CT and MRI, which opens up new applications of ultrasound imaging in electromagnetically challenging settings.
光学超声（OpUS）成像是一种利用光纤超声源和探测器进行脉冲回波超声成像的超声模式。这些探头可完全由玻璃光纤和塑料部件制成，因此，人们预测这些设备可与使用强电磁场成像的计算机断层扫描（CT）和磁共振成像（MRI）兼容。然而，迄今为止，这种兼容性尚未得到证实。在这项工作中，我们专门开发了一种自由手持式 OpUS 成像系统，以研究 OpUS 系统与 CT 和 MRI 成像系统的兼容性。这项工作中讨论的 OpUS 成像平台用于在（单独）同时进行的 CT 和 MRI 下进行实时 OpUS 成像。OpUS探头的CT和MRI成像用于确定探头本身是否会在CT和MRI成像中产生伪影，超声分辨率目标和背景测量用于评估CT和MRI对OpUS信号保真度的影响。这些测量结果表明，OpUS 系统与 CT 和 MRI 系统之间的相互作用可以忽略不计，为了进一步证明这种能力，对一个组织模拟模型和一个动态运动模型同时进行了 OpUS-CT 和 OpUS-MRI 成像。这项工作全面展示了与 CT 和 MRI 同时运行的 OpUS 成像系统，开辟了超声成像在电磁挑战环境中的新应用。
{"title":"Multimodal optical ultrasound imaging: Real-time imaging under concurrent CT or MRI","authors":"Fraser T. Watt, Vivek Muthurangu, Jennifer Steeden, Eleanor C. Mackle, Adrien E. Desjardins, Edward Z. Zhang, Paul C. Beard, Erwin J. Alles","doi":"10.1063/5.0225554","DOIUrl":"https://doi.org/10.1063/5.0225554","url":null,"abstract":"Optical ultrasound (OpUS) imaging is an ultrasound modality that utilizes fiber-optic ultrasound sources and detectors to perform pulse-echo ultrasound imaging. These probes can be constructed entirely from glass optical fibers and plastic components, and as such, these devices have been predicted to be compatible with computed tomography (CT) and magnetic resonance imaging (MRI), modalities that use intense electromagnetic fields for imaging. However, to date, this compatibility has not been demonstrated. In this work, a free-hand OpUS imaging system was developed specifically to investigate the compatibility of OpUS systems with CT and MRI imaging systems. The OpUS imaging platform discussed in this work was used to perform real-time OpUS imaging under (separately) concurrent CT and MRI. CT and MRI imaging of the OpUS probe was used to determine if the probe itself would induce artifacts in the CT and MRI imaging, and ultrasound resolution targets and background measurements were used to assess any impact of CT and MRI on the OpUS signal fidelity. These measurements demonstrate that there was negligible interaction between the OpUS system and both the CT and MRI systems, and to further demonstrate this capability, concurrent OpUS-CT and OpUS-MRI imaging was conducted of a tissue-mimicking phantom and a dynamic motion phantom. This work presents a comprehensive demonstration of an OpUS imaging system operating alongside CT and MRI, which opens up new applications of ultrasound imaging in electromagnetically challenging settings.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"144 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199471","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}
Mid-infrared (MIR) photonic integration is desirable in the development of MIR spectroscopy and “lab-on-a-chip” sensing. The germanium-on-silicon (GOS) platform offers a promising solution for MIR photonic integration, extending the operational wavelength to a longer band by eliminating the light-absorbing buried oxide layer. However, MIR photodetectors on the GOS platform remain undeveloped due to the challenging heterogeneous integration of active materials on silicon and inadequate light absorption in the photodetection region. Here, we demonstrate a photo-thermoelectric graphene photodetector on the GOS platform, taking advantage of zero-bias operation and easy heterogeneous integration of graphene. By employing split-gate architecture and plasmonic enhancement to strengthen the light-graphene interaction, we achieve a responsivity of 1.97 V W−1 and noise equivalent power of 2.8 nW Hz−1/2 at the wavelength of 3.7 µm. This work enables waveguide-integrated MIR photodetection on the GOS platform for the first time, and it holds great potential for on-chip MIR sensing and imaging applications.
{"title":"Mid-infrared waveguide-integrated and photo-thermoelectric graphene photodetector based on germanium-on-silicon platform","authors":"Hongjun Cai, Changming Yang, Yuheng Liu, Xinliang Zhang, Yi Zou, Yu Yu","doi":"10.1063/5.0218976","DOIUrl":"https://doi.org/10.1063/5.0218976","url":null,"abstract":"Mid-infrared (MIR) photonic integration is desirable in the development of MIR spectroscopy and “lab-on-a-chip” sensing. The germanium-on-silicon (GOS) platform offers a promising solution for MIR photonic integration, extending the operational wavelength to a longer band by eliminating the light-absorbing buried oxide layer. However, MIR photodetectors on the GOS platform remain undeveloped due to the challenging heterogeneous integration of active materials on silicon and inadequate light absorption in the photodetection region. Here, we demonstrate a photo-thermoelectric graphene photodetector on the GOS platform, taking advantage of zero-bias operation and easy heterogeneous integration of graphene. By employing split-gate architecture and plasmonic enhancement to strengthen the light-graphene interaction, we achieve a responsivity of 1.97 V W−1 and noise equivalent power of 2.8 nW Hz−1/2 at the wavelength of 3.7 µm. This work enables waveguide-integrated MIR photodetection on the GOS platform for the first time, and it holds great potential for on-chip MIR sensing and imaging applications.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"14 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199472","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}
In this paper, a novel approach based on frequency upconversion in ultra-thin nonlinear crystals is investigated for use in high-resolution infrared (IR) microscopy in the 5–12 µm range, an important domain for biomedical research. Traditional IR imaging encounters spatial resolution constraints due to diffraction, which are addressed via upconversion imaging using ultra-thin crystals. The present work combines a tunable IR quantum cascade laser and a short wavelength mixing laser to circumvent the classical resolution limit dictated by the Rayleigh criterion. A detailed numerical model for small signal upconversion imaging at μm-scale resolution shows good agreement with experimental data. The presented approach opens new avenues for IR applications for label-free biomedical diagnostics and spectral imaging.
{"title":"Long-wavelength, high-resolution microscopy using upconversion in ultra-thin crystals","authors":"P. Tidemand-Lichtenberg, C. Pedersen","doi":"10.1063/5.0217145","DOIUrl":"https://doi.org/10.1063/5.0217145","url":null,"abstract":"In this paper, a novel approach based on frequency upconversion in ultra-thin nonlinear crystals is investigated for use in high-resolution infrared (IR) microscopy in the 5–12 µm range, an important domain for biomedical research. Traditional IR imaging encounters spatial resolution constraints due to diffraction, which are addressed via upconversion imaging using ultra-thin crystals. The present work combines a tunable IR quantum cascade laser and a short wavelength mixing laser to circumvent the classical resolution limit dictated by the Rayleigh criterion. A detailed numerical model for small signal upconversion imaging at μm-scale resolution shows good agreement with experimental data. The presented approach opens new avenues for IR applications for label-free biomedical diagnostics and spectral imaging.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"237 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199473","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}
We present deep-ultraviolet Fourier ptychography (DUV-FP) for high-resolution chemical imaging of biological specimens in their native state without exogenous stains. This approach uses a customized 265-nm DUV LED array for angle-varied illumination, leveraging the unique DUV absorption properties of biomolecules at this wavelength region. We implemented a robust feature-domain optimization framework to overcome common challenges in Fourier ptychographic reconstruction, including vignetting, pupil aberrations, stray light problems, intensity variations, and other systematic errors. By using a 0.12 numerical aperture low-resolution objective lens, our DUV-FP prototype can resolve the 345-nm linewidth on a resolution target, demonstrating at least a four-fold resolution gain compared to the captured raw images. Testing on various biospecimens demonstrates that DUV-FP significantly enhances absorption-based chemical contrast and reveals detailed structural and molecular information. To further address the limitations of conventional FP in quantitative phase imaging, we developed a spatially coded DUV-FP system. This platform enables true quantitative phase imaging of biospecimens with DUV light, overcoming the non-uniform phase response inherent in traditional microscopy techniques. The demonstrated advancements in high-resolution, label-free chemical imaging may accelerate developments in digital pathology, potentially enabling rapid, on-site analysis of biopsy samples in clinical settings.
{"title":"Deep-ultraviolet Fourier ptychography (DUV-FP) for label-free biochemical imaging via feature-domain optimization.","authors":"Qianhao Zhao, Ruihai Wang, Shuhe Zhang, Tianbo Wang, Pengming Song, Guoan Zheng","doi":"10.1063/5.0227038","DOIUrl":"https://doi.org/10.1063/5.0227038","url":null,"abstract":"<p><p>We present deep-ultraviolet Fourier ptychography (DUV-FP) for high-resolution chemical imaging of biological specimens in their native state without exogenous stains. This approach uses a customized 265-nm DUV LED array for angle-varied illumination, leveraging the unique DUV absorption properties of biomolecules at this wavelength region. We implemented a robust feature-domain optimization framework to overcome common challenges in Fourier ptychographic reconstruction, including vignetting, pupil aberrations, stray light problems, intensity variations, and other systematic errors. By using a 0.12 numerical aperture low-resolution objective lens, our DUV-FP prototype can resolve the 345-nm linewidth on a resolution target, demonstrating at least a four-fold resolution gain compared to the captured raw images. Testing on various biospecimens demonstrates that DUV-FP significantly enhances absorption-based chemical contrast and reveals detailed structural and molecular information. To further address the limitations of conventional FP in quantitative phase imaging, we developed a spatially coded DUV-FP system. This platform enables true quantitative phase imaging of biospecimens with DUV light, overcoming the non-uniform phase response inherent in traditional microscopy techniques. The demonstrated advancements in high-resolution, label-free chemical imaging may accelerate developments in digital pathology, potentially enabling rapid, on-site analysis of biopsy samples in clinical settings.</p>","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"9 9","pages":"090801"},"PeriodicalIF":5.4,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11409226/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142279720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
π modes are unique topological edge states appearing in Floquet systems with periodic modulations of the underlying lattice structure in the evolution variable, such as dynamically modulated Su–Schrieffer–Heeger (SSH) lattices. These edge states are anomalous states usually appearing between Floquet replicas of the same band, even if the standard topological index remains zero for this band. While linear and nonlinear π modes were observed in conservative systems, they have never been studied in the nonlinear regime in the non-Hermitian systems with structured gain and losses. Here, we show that the SSH waveguide array with periodically oscillating waveguide positions in the propagation direction and with the parity-time symmetric refractive index landscape can support π modes that are damped or amplified at different ends of the array. By including nonlinearity and nonlinear absorption into our continuous system, we achieve stable lasing in the π mode at one end of the array. The representative feature of this system is that lasing in it is thresholdless and occurs even at low gain–loss amplitudes. The degree of localization of lasing π modes can be flexibly controlled by the amplitude of transverse waveguide oscillations. This work therefore introduces a new type of topological Floquet laser and a route to manipulate π modes by structured gain and losses.
{"title":"π mode lasing in the non-Hermitian Floquet topological system","authors":"Shuang Shen, Yaroslav V. Kartashov, Yongdong Li, Meng Cao, Yiqi Zhang","doi":"10.1063/5.0217904","DOIUrl":"https://doi.org/10.1063/5.0217904","url":null,"abstract":"π modes are unique topological edge states appearing in Floquet systems with periodic modulations of the underlying lattice structure in the evolution variable, such as dynamically modulated Su–Schrieffer–Heeger (SSH) lattices. These edge states are anomalous states usually appearing between Floquet replicas of the same band, even if the standard topological index remains zero for this band. While linear and nonlinear π modes were observed in conservative systems, they have never been studied in the nonlinear regime in the non-Hermitian systems with structured gain and losses. Here, we show that the SSH waveguide array with periodically oscillating waveguide positions in the propagation direction and with the parity-time symmetric refractive index landscape can support π modes that are damped or amplified at different ends of the array. By including nonlinearity and nonlinear absorption into our continuous system, we achieve stable lasing in the π mode at one end of the array. The representative feature of this system is that lasing in it is thresholdless and occurs even at low gain–loss amplitudes. The degree of localization of lasing π modes can be flexibly controlled by the amplitude of transverse waveguide oscillations. This work therefore introduces a new type of topological Floquet laser and a route to manipulate π modes by structured gain and losses.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"4 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199474","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}
Daniel Krizan, Jiri Stipal, Jan Nedoma, Sandro Oliveira, Marcel Fajkus, Jakub Cubik, Petr Siska, Emiliano Schena, Daniela Lo Presti, Carlos Marques
Fiber optic sensors based on fiber Bragg grating (FBG) technology have the potential to revolutionize the way vital signs of the human body are measured and monitored. By leveraging their unique properties, these sensors can provide accurate and reliable data, thus enhancing the effectiveness of wearable devices. The integration of FBG sensors into different materials not only broadens their application scope but also improves user comfort and device practicality. However, some challenges remain in optimizing the embedding process to ensure sensor performance and durability. This review provides an overview of FBG technology employed for measuring vital signs of the human body reported in the past decade. The focus of the review is on the FBG embedding strategies into different materials, categorized into these three main groups (i.e., 3D printed, textiles, and polymers) and explores the implications of embedding fiber optic sensors in each category. Furthermore, it discusses the potential impact of these embedded sensors on the accuracy, comfort, and practicality of wearable devices designed for monitoring vital signs, highlighting the potential of these sensors to transform the field of health monitoring. Future research directions may include exploring new materials for embedding and refining sensor design further to improve the accuracy and comfort of these wearable devices. Ultimately, the evolution of fiber optic sensors could significantly advance the field of human vital sign monitoring, paving the way for more sophisticated and user-friendly health monitoring systems.
基于光纤布拉格光栅（FBG）技术的光纤传感器有望彻底改变测量和监测人体生命体征的方式。利用其独特的特性，这些传感器可以提供准确可靠的数据，从而提高可穿戴设备的功效。将 FBG 传感器集成到不同的材料中，不仅拓宽了其应用范围，还提高了用户舒适度和设备实用性。然而，在优化嵌入工艺以确保传感器性能和耐用性方面仍存在一些挑战。本综述概述了过去十年中用于测量人体生命体征的 FBG 技术。综述的重点是不同材料中的 FBG 嵌入策略，分为三大类（即 3D 打印、纺织品和聚合物），并探讨了在每一类材料中嵌入光纤传感器的影响。此外，报告还讨论了这些嵌入式传感器对用于监测生命体征的可穿戴设备的准确性、舒适性和实用性的潜在影响，强调了这些传感器改变健康监测领域的潜力。未来的研究方向可能包括探索新的嵌入材料和进一步完善传感器设计，以提高这些可穿戴设备的准确性和舒适性。最终，光纤传感器的发展将极大地推动人体生命体征监测领域的发展，为更先进、更方便用户的健康监测系统铺平道路。
{"title":"Embedding FBG sensors for monitoring vital signs of the human body: Recent progress over the past decade","authors":"Daniel Krizan, Jiri Stipal, Jan Nedoma, Sandro Oliveira, Marcel Fajkus, Jakub Cubik, Petr Siska, Emiliano Schena, Daniela Lo Presti, Carlos Marques","doi":"10.1063/5.0226556","DOIUrl":"https://doi.org/10.1063/5.0226556","url":null,"abstract":"Fiber optic sensors based on fiber Bragg grating (FBG) technology have the potential to revolutionize the way vital signs of the human body are measured and monitored. By leveraging their unique properties, these sensors can provide accurate and reliable data, thus enhancing the effectiveness of wearable devices. The integration of FBG sensors into different materials not only broadens their application scope but also improves user comfort and device practicality. However, some challenges remain in optimizing the embedding process to ensure sensor performance and durability. This review provides an overview of FBG technology employed for measuring vital signs of the human body reported in the past decade. The focus of the review is on the FBG embedding strategies into different materials, categorized into these three main groups (i.e., 3D printed, textiles, and polymers) and explores the implications of embedding fiber optic sensors in each category. Furthermore, it discusses the potential impact of these embedded sensors on the accuracy, comfort, and practicality of wearable devices designed for monitoring vital signs, highlighting the potential of these sensors to transform the field of health monitoring. Future research directions may include exploring new materials for embedding and refining sensor design further to improve the accuracy and comfort of these wearable devices. Ultimately, the evolution of fiber optic sensors could significantly advance the field of human vital sign monitoring, paving the way for more sophisticated and user-friendly health monitoring systems.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"10 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199475","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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