Pub Date : 2026-01-05DOI: 10.1109/JSTQE.2025.3650463
Kung-An Lin;Thu Huong Bui;Lucas Yang;Chao-Hsin Wu
Flip-chip bonding is a promising technique for integrating Vertical-Cavity Surface-Emitting Lasers (VCSELs) in Co-Packaged Optics (CPO) for high-speed applications, but it requires careful optimization of Gold (Au) bumps bonding parameters to address thermal management, ensure efficient optical coupling, and enhance device performance. This study investigates the packaging performance of a VCSEL array integrated onto silicon interposers using flip-chip bonding with Au bumps under various bonding conditions. Emphasis is placed on the effects of bump flattening and alignment accuracy on bonding quality and overall device performance. Au bumps with flattened surfaces and optimized misalignment were analyzed through SEM imaging, luminescence testing, and L-I-V (Light–Current–Voltage) characterization. Results show that flattening Au bumps and a small misalignment between the two Au bumps significantly improve surface planarity and enhance both electrical and optical performance. Finite Element Analysis (FEA) simulations are also conducted to compare with experimental results and provide further insight into stress distribution and structural behavior. The findings underscore the importance of bump flattening and precise alignment in ensuring mechanical reliability and achieving optimal performance in VCSEL-based optical interconnects for next-generation CPO systems.
{"title":"3D Heterogeneous Integration of Back-Emitting VCSEL Arrays via Flip-Chip Bonding for Co-Packaged Optics Systems","authors":"Kung-An Lin;Thu Huong Bui;Lucas Yang;Chao-Hsin Wu","doi":"10.1109/JSTQE.2025.3650463","DOIUrl":"https://doi.org/10.1109/JSTQE.2025.3650463","url":null,"abstract":"Flip-chip bonding is a promising technique for integrating Vertical-Cavity Surface-Emitting Lasers (VCSELs) in Co-Packaged Optics (CPO) for high-speed applications, but it requires careful optimization of Gold (Au) bumps bonding parameters to address thermal management, ensure efficient optical coupling, and enhance device performance. This study investigates the packaging performance of a VCSEL array integrated onto silicon interposers using flip-chip bonding with Au bumps under various bonding conditions. Emphasis is placed on the effects of bump flattening and alignment accuracy on bonding quality and overall device performance. Au bumps with flattened surfaces and optimized misalignment were analyzed through SEM imaging, luminescence testing, and L-I-V (Light–Current–Voltage) characterization. Results show that flattening Au bumps and a small misalignment between the two Au bumps significantly improve surface planarity and enhance both electrical and optical performance. Finite Element Analysis (FEA) simulations are also conducted to compare with experimental results and provide further insight into stress distribution and structural behavior. The findings underscore the importance of bump flattening and precise alignment in ensuring mechanical reliability and achieving optimal performance in VCSEL-based optical interconnects for next-generation CPO systems.","PeriodicalId":13094,"journal":{"name":"IEEE Journal of Selected Topics in Quantum Electronics","volume":"32 2: 3-D Horizons in Photonics: Integrated Circuits","pages":"1-8"},"PeriodicalIF":5.1,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Terahertz (THz) waves located in an important electromagnetic frequency band have unique characteristics and great application prospects in rapid, non-destructive, and marker-free biomedical detection. Benefiting from Fano resonance has the advantages of high local field enhancement and low loss, we propose a graphene-integrated asymmetric U-type split-ring (Gr-AUSR) Fano resonance metasurfaces THz biosensor. Experimental results show that the Fano resonance intensity of the proposed Gr-AUSR sensor can be altered by the Fermi level shift of chemical vapor deposition (CVD) graphene under slight external stimuli, achieving a minimum midkine (MK) detection limit of 125 pg/ml. Moreover, we extract the maximum wavelet coefficient from the two-dimensional wavelet time-frequency diagram, combining with the Fano resonance amplitude and effective transmission area to construct a multiscale pyramid-shaped model, where its volumes intuitively correspond to different MK concentrations. This work paves the way toward designing and developing of ultra-sensitive biosensors for picogram-levels biological detection at THz frequencies.
{"title":"Fano-Resonant Asymmetric U-Type Metasurfaces Integrating Graphene for Trace Biosensing at Thz Frequencies","authors":"Tongling Wang;Qiyu Ying;Xiangyuan Meng;Yilong Xin;Ziqi Li;Mingyao Wang;Changshun Wu;Li Wang;Maosheng Yang;Xiuwei Yang;Wenjing Zheng;Maojing Liu","doi":"10.1109/JSTQE.2025.3649886","DOIUrl":"https://doi.org/10.1109/JSTQE.2025.3649886","url":null,"abstract":"Terahertz (THz) waves located in an important electromagnetic frequency band have unique characteristics and great application prospects in rapid, non-destructive, and marker-free biomedical detection. Benefiting from Fano resonance has the advantages of high local field enhancement and low loss, we propose a graphene-integrated asymmetric U-type split-ring (Gr-AUSR) Fano resonance metasurfaces THz biosensor. Experimental results show that the Fano resonance intensity of the proposed Gr-AUSR sensor can be altered by the Fermi level shift of chemical vapor deposition (CVD) graphene under slight external stimuli, achieving a minimum midkine (MK) detection limit of 125 pg/ml. Moreover, we extract the maximum wavelet coefficient from the two-dimensional wavelet time-frequency diagram, combining with the Fano resonance amplitude and effective transmission area to construct a multiscale pyramid-shaped model, where its volumes intuitively correspond to different MK concentrations. This work paves the way toward designing and developing of ultra-sensitive biosensors for picogram-levels biological detection at THz frequencies.","PeriodicalId":13094,"journal":{"name":"IEEE Journal of Selected Topics in Quantum Electronics","volume":"32 3: Nanophotonics, Metamaterials and Plasmonics","pages":"1-8"},"PeriodicalIF":5.1,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In SD-OCT, linear-in-wavenumber spectrometers play a key role in direct k-domain sampling, which eliminates interpolation artifacts and reduces computational load. However, prevalent designs in the 850 nm band using 1200 lines/mm gratings face a fundamental trade-off between imaging depth, system size and cost: achieving a large imaging depth necessitates large-volume, costly optics with long focal lengths and large apertures. To overcome this limitation, we present the design and experimental validation of a linear-in-wavenumber spectrometer employing a 1800 lines/mm grating. The high dispersion of this grating enables a compact system that achieves an imaging depth of ∼4.8 mm with a 76 nm spectral detection range, compatible with single-SLD sources. Compared to the conventional 1200 lines/mm design, our spectrometer reduces the total optical length from ∼325 mm to ∼190 mm and the entrance pupil diameter from 11 mm to 7.2 mm, allowing for smaller and more cost-effective components. Furthermore, our optimization method incorporates wavenumber nonlinearity introduced by the focusing group, overcoming the limitations of traditional approaches that neglect lens aberrations. Experimental results demonstrate a considerable wavenumber linearity (R2 = 0.9999995) and a system sensitivity of 103.4 dB. High-quality in vivo imaging of human skin and nailfold, revealing microvasculature and layered structures, validates the practical utility. This work provides a high-linearity, compact, and cost-effective spectrometer solution, particularly suited for SD-OCT applications requiring large imaging depths.
{"title":"A Compact Linear-in-Wavenumber Spectrometer With a 1800 Lines/mm Grating for 4.8 mm Imaging Depth in SD-OCT","authors":"Liangqi Cao;Haozhe Zhong;Duohao Zhao;Wenxin Zhang;Jianfeng Huang;Jiacheng Zhang;Xiao Zhang","doi":"10.1109/JSTQE.2025.3649911","DOIUrl":"https://doi.org/10.1109/JSTQE.2025.3649911","url":null,"abstract":"In SD-OCT, linear-in-wavenumber spectrometers play a key role in direct k-domain sampling, which eliminates interpolation artifacts and reduces computational load. However, prevalent designs in the 850 nm band using 1200 lines/mm gratings face a fundamental trade-off between imaging depth, system size and cost: achieving a large imaging depth necessitates large-volume, costly optics with long focal lengths and large apertures. To overcome this limitation, we present the design and experimental validation of a linear-in-wavenumber spectrometer employing a 1800 lines/mm grating. The high dispersion of this grating enables a compact system that achieves an imaging depth of ∼4.8 mm with a 76 nm spectral detection range, compatible with single-SLD sources. Compared to the conventional 1200 lines/mm design, our spectrometer reduces the total optical length from ∼325 mm to ∼190 mm and the entrance pupil diameter from 11 mm to 7.2 mm, allowing for smaller and more cost-effective components. Furthermore, our optimization method incorporates wavenumber nonlinearity introduced by the focusing group, overcoming the limitations of traditional approaches that neglect lens aberrations. Experimental results demonstrate a considerable wavenumber linearity (R<sup>2</sup> = 0.9999995) and a system sensitivity of 103.4 dB. High-quality in vivo imaging of human skin and nailfold, revealing microvasculature and layered structures, validates the practical utility. This work provides a high-linearity, compact, and cost-effective spectrometer solution, particularly suited for SD-OCT applications requiring large imaging depths.","PeriodicalId":13094,"journal":{"name":"IEEE Journal of Selected Topics in Quantum Electronics","volume":"32 4: Adv. Biophoton. in Emerg. Biomed. Tech. and Dev","pages":"1-8"},"PeriodicalIF":5.1,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, we demonstrate GaN-based photonic crystal surface-emitting lasers (PCSELs) employing two distinct air hole geometries: circular (CC) and right-isosceles-triangle (RIT). By systematically tuning the fill factor (FF) and lattice constant, the lasing wavelengths are maintained between 420–425 nm, enabling direct comparison of device performance. Optical simulations and experimental results confirm that the CC structure, characterized by high in-plane symmetry (C4v group), supports degenerate Bloch modes at the Γ point, resulting in strong lateral confinement, low vertical radiation loss, and high Q-factors. These features enable low-threshold lasing. In contrast, the RIT structure intentionally breaks the in-plane rotational symmetry, lifting mode degeneracy via geometric asymmetry. This mode splitting selectively enhances the vertical radiation coupling of the desired B-mode while suppressing competing modes, facilitating stable single-mode operation. Although the RIT design yields a higher threshold due to the increased vertical loss, it also demonstrates superior slope efficiency beyond the threshold. The declining threshold trend with increasing FF in both configurations matches the simulated predictions.
{"title":"Impact of Air Hole Geometry on the Performance of InGaN/GaN Photonic Crystal Surface-Emitting Lasers","authors":"Wen-Hsuan Hsieh;Kuo-Bin Hong;Ching-Han Lin;Chen-Yu Yang;Tien-Chang Lu;Chia-Yen Huang","doi":"10.1109/JSTQE.2025.3650007","DOIUrl":"https://doi.org/10.1109/JSTQE.2025.3650007","url":null,"abstract":"In this study, we demonstrate GaN-based photonic crystal surface-emitting lasers (PCSELs) employing two distinct air hole geometries: circular (CC) and right-isosceles-triangle (RIT). By systematically tuning the fill factor (FF) and lattice constant, the lasing wavelengths are maintained between 420–425 nm, enabling direct comparison of device performance. Optical simulations and experimental results confirm that the CC structure, characterized by high in-plane symmetry (C<sub>4v</sub> group), supports degenerate Bloch modes at the Γ point, resulting in strong lateral confinement, low vertical radiation loss, and high Q-factors. These features enable low-threshold lasing. In contrast, the RIT structure intentionally breaks the in-plane rotational symmetry, lifting mode degeneracy via geometric asymmetry. This mode splitting selectively enhances the vertical radiation coupling of the desired B-mode while suppressing competing modes, facilitating stable single-mode operation. Although the RIT design yields a higher threshold due to the increased vertical loss, it also demonstrates superior slope efficiency beyond the threshold. The declining threshold trend with increasing FF in both configurations matches the simulated predictions.","PeriodicalId":13094,"journal":{"name":"IEEE Journal of Selected Topics in Quantum Electronics","volume":"32 6: Special on Advances in VCSELs and PCSELs","pages":"1-6"},"PeriodicalIF":5.1,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146006901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-31DOI: 10.1109/JSTQE.2025.3650043
Robert T. Schwarz;Hung Le Son;Marcus T. Knopp;Andreas Knopp
Optical feeder links (OFLs) to geostationary orbit (GEO) satellites present a promising solution to significantly enhance the throughput of satellite systems, especially those with high data rate demands, such as satellite constellations. However, cloud coverage substantially increases the likelihood of link outages, thereby reducing the availability of optical ground stations (OGSs) and limiting the number of possible connections between the GEO and OGS networks. This paper introduces a maxflow-based OFL planning concept aimed at maximizing the number of ground-to-GEO OFL connections under the influence of dynamic cloud coverage. Various network scenarios are considered—featuring different numbers of satellites, OGSs, and varying degrees of visibility correlation—to optimize the network design. The average system capacity is estimated through Monte Carlo simulations, while system availability is stochastically evaluated. Simulation results show that network capacity depends mainly on the number of GEO satellites, while visibility correlation has a strong impact on availability. Furthermore, the simulations reveal that even under a high correlation of visibility and a high probability of link outages, only a small number of additional OGSs are sufficient to achieve the theoretical upper bound of capacity. These insights can contribute to costefficient network design by identifying the optimal number of GEO satellites and OGSs required to meet operational demands.
{"title":"Optical Feeder Links for Multi-GEO Multi-OGS Networks: Nodes Analysis to Maximize Connectivity Under Dynamic Cloud Coverage","authors":"Robert T. Schwarz;Hung Le Son;Marcus T. Knopp;Andreas Knopp","doi":"10.1109/JSTQE.2025.3650043","DOIUrl":"https://doi.org/10.1109/JSTQE.2025.3650043","url":null,"abstract":"Optical feeder links (OFLs) to geostationary orbit (GEO) satellites present a promising solution to significantly enhance the throughput of satellite systems, especially those with high data rate demands, such as satellite constellations. However, cloud coverage substantially increases the likelihood of link outages, thereby reducing the availability of optical ground stations (OGSs) and limiting the number of possible connections between the GEO and OGS networks. This paper introduces a maxflow-based OFL planning concept aimed at maximizing the number of ground-to-GEO OFL connections under the influence of dynamic cloud coverage. Various network scenarios are considered—featuring different numbers of satellites, OGSs, and varying degrees of visibility correlation—to optimize the network design. The average system capacity is estimated through Monte Carlo simulations, while system availability is stochastically evaluated. Simulation results show that network capacity depends mainly on the number of GEO satellites, while visibility correlation has a strong impact on availability. Furthermore, the simulations reveal that even under a high correlation of visibility and a high probability of link outages, only a small number of additional OGSs are sufficient to achieve the theoretical upper bound of capacity. These insights can contribute to costefficient network design by identifying the optimal number of GEO satellites and OGSs required to meet operational demands.","PeriodicalId":13094,"journal":{"name":"IEEE Journal of Selected Topics in Quantum Electronics","volume":"32 1: Advances in Free Space Laser Communications","pages":"1-8"},"PeriodicalIF":5.1,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11320252","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145982274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-30DOI: 10.1109/JSTQE.2025.3649420
Naim Slim;Vadzim Chalau;Sara Sousi;Maxime Giot;Ioannis Gkouzionnis;Robert Goldin;Josephine Lloyd;Priscilla Anketell;Ara Darzi;Christopher J. Peters;Daniel S. Elson
Intraoperative assessment of lymph node metastasis remains a major challenge during cancer surgery. Diffuse Reflectance Spectroscopy (DRS) is a point-based technique that has the potential to offer rapid diagnosis, but the technological limits of this technique have not been well defined for this application. We acquired over 11000 spectra from 99 lymph nodes excised from 26 patients undergoing gastric or oesophageal cancer resection, and utilised these to derive optical properties for benign node, malignant node and adipose tissue. Monte Carlo simulations were then utilised to model photon transport in a wide array of simulated nodes with varying metastatic focus sizes and depths, lymph node sizes and depths, and DRS probe source-detector separations. Our simulations demonstrated a ‘thoretical minimum’ micrometastatic focus detectable by DRS of approximately 350–600 $mu$m. Increasing source-detector separation extended the depth of probing but raised the minimum focus diameter detectable with DRS, indicating a trade-off effect between depth penetration and micrometastasis detection. Our findings reveal the potential for DRS to be utilised as a real-time intraoperative spectroscopic method for the detection of lymph node metastases, and establish the basis for DRS probe design optimisation.
{"title":"Monte Carlo Photon-Transport Modelling of Diffuse Reflectance Spectroscopy in Heterogenous Lymph Node Models","authors":"Naim Slim;Vadzim Chalau;Sara Sousi;Maxime Giot;Ioannis Gkouzionnis;Robert Goldin;Josephine Lloyd;Priscilla Anketell;Ara Darzi;Christopher J. Peters;Daniel S. Elson","doi":"10.1109/JSTQE.2025.3649420","DOIUrl":"https://doi.org/10.1109/JSTQE.2025.3649420","url":null,"abstract":"Intraoperative assessment of lymph node metastasis remains a major challenge during cancer surgery. Diffuse Reflectance Spectroscopy (DRS) is a point-based technique that has the potential to offer rapid diagnosis, but the technological limits of this technique have not been well defined for this application. We acquired over 11000 spectra from 99 lymph nodes excised from 26 patients undergoing gastric or oesophageal cancer resection, and utilised these to derive optical properties for benign node, malignant node and adipose tissue. Monte Carlo simulations were then utilised to model photon transport in a wide array of simulated nodes with varying metastatic focus sizes and depths, lymph node sizes and depths, and DRS probe source-detector separations. Our simulations demonstrated a ‘thoretical minimum’ micrometastatic focus detectable by DRS of approximately 350–600 <inline-formula><tex-math>$mu$</tex-math></inline-formula>m. Increasing source-detector separation extended the depth of probing but raised the minimum focus diameter detectable with DRS, indicating a trade-off effect between depth penetration and micrometastasis detection. Our findings reveal the potential for DRS to be utilised as a real-time intraoperative spectroscopic method for the detection of lymph node metastases, and establish the basis for DRS probe design optimisation.","PeriodicalId":13094,"journal":{"name":"IEEE Journal of Selected Topics in Quantum Electronics","volume":"32 4: Adv. Biophoton. in Emerg. Biomed. Tech. and Dev","pages":"1-12"},"PeriodicalIF":5.1,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-25DOI: 10.1109/JSTQE.2025.3648470
Takhellambam Gautam Meitei;Pi-Shan Hsu;Wei-Wen Lin;Yi-Min Wang;Liang-Kung Chen;Chia-Wei Sun
This study evaluates the potential of combining Near-Infrared Spectroscopy (NIRS) and Laser Doppler Flowmetry (LDF) to classify cardiovascular disease (CVD) risk in elderly individuals based on peripheral microvascular function. Signals were acquired during a standardized thermal challenge and processed to extract dynamic physiological features, including time-domain statistics, wavelet-derived spectral components, and engineered indices such as recovery efficiency and vascular coupling. A Random Forest classifier achieved 81.5% cross-validation accuracy (95% CI: [76.2%, 86.8%]) with an area under the ROC curve (AUC) of 0.911 (95% CI: [0.865, 0.950]). Dimensionality reduction via Principal Component Analysis preserved model performance while enabling data visualization. Feature importance analysis highlighted recovery-phase metrics and engineered indicators, such as LDF recovery efficiency, HbO$_{2}$ recovery mean, and oxy-flow coupling, as key contributors to classification. These findings support the integration of multimodal optical biosignals and microvascular reactivity profiling as a promising strategy for noninvasive cardiovascular risk stratification in aging populations.
{"title":"Vascular Reactivity Fingerprints Predict Cardiovascular Risk via Thermal-Stressed Optical Profiling: A Dual Near-Infrared Spectroscopy and Laser Doppler Flowmetry Approach","authors":"Takhellambam Gautam Meitei;Pi-Shan Hsu;Wei-Wen Lin;Yi-Min Wang;Liang-Kung Chen;Chia-Wei Sun","doi":"10.1109/JSTQE.2025.3648470","DOIUrl":"https://doi.org/10.1109/JSTQE.2025.3648470","url":null,"abstract":"This study evaluates the potential of combining Near-Infrared Spectroscopy (NIRS) and Laser Doppler Flowmetry (LDF) to classify cardiovascular disease (CVD) risk in elderly individuals based on peripheral microvascular function. Signals were acquired during a standardized thermal challenge and processed to extract dynamic physiological features, including time-domain statistics, wavelet-derived spectral components, and engineered indices such as recovery efficiency and vascular coupling. A Random Forest classifier achieved 81.5% cross-validation accuracy (95% CI: [76.2%, 86.8%]) with an area under the ROC curve (AUC) of 0.911 (95% CI: [0.865, 0.950]). Dimensionality reduction via Principal Component Analysis preserved model performance while enabling data visualization. Feature importance analysis highlighted recovery-phase metrics and engineered indicators, such as LDF recovery efficiency, HbO<inline-formula><tex-math>$_{2}$</tex-math></inline-formula> recovery mean, and oxy-flow coupling, as key contributors to classification. These findings support the integration of multimodal optical biosignals and microvascular reactivity profiling as a promising strategy for noninvasive cardiovascular risk stratification in aging populations.","PeriodicalId":13094,"journal":{"name":"IEEE Journal of Selected Topics in Quantum Electronics","volume":"32 4: Adv. Biophoton. in Emerg. Biomed. Tech. and Dev","pages":"1-14"},"PeriodicalIF":5.1,"publicationDate":"2025-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11316253","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-23DOI: 10.1109/JSTQE.2025.3647224
Yuriy I. Surkov;Isabella A. Serebryakova;Arseniy P. Fashchevskiy;Polina A. Timoshina;Elina A. Genina;Valery V. Tuchin
We present a principal component analysis-based Laser Speckle Contrast Tomography (PCA-LSCT) method that enables simultaneous, independent mapping of vessel depth and blood-flow velocity without any modification to the optical layout of conventional laser speckle contrast imaging (LSCI). Raw speckle frames are decomposed by a principal component analysis into a static component–the Static Speckle Contrast (SSC)–and a dynamic component–the Dynamic Activity Coefficient (DAC). The SSC is linearly correlated with the relative depth of vessels and is invariant to flow speed, whereas the DAC quantifies blood-flow velocity analogously to classical LSCI and is only weakly depth-dependent. Experiments with phantoms containing a model capillary and flow velocities ranging from 1 to 50 mm/s demonstrate high reproducibility of SSC profiles and a strong correlation between the resulting depth maps and ultrasound tomography (r2 = 0.90 for transmitted-light detection, r2 = 0.88 for backscattered-light detection). The suggested approach has been tested in vivo on a ring finger and has confirmed its high potential for providing non-invasive, contactless, depth-resolved 3D angiography.
{"title":"PCA-LSCT: Software-Implemented Laser Speckle Contrast Tomography for Depth-Resolved Blood-Flow Mapping","authors":"Yuriy I. Surkov;Isabella A. Serebryakova;Arseniy P. Fashchevskiy;Polina A. Timoshina;Elina A. Genina;Valery V. Tuchin","doi":"10.1109/JSTQE.2025.3647224","DOIUrl":"https://doi.org/10.1109/JSTQE.2025.3647224","url":null,"abstract":"We present a principal component analysis-based Laser Speckle Contrast Tomography (PCA-LSCT) method that enables simultaneous, independent mapping of vessel depth and blood-flow velocity without any modification to the optical layout of conventional laser speckle contrast imaging (LSCI). Raw speckle frames are decomposed by a principal component analysis into a static component–the <italic>Static Speckle Contrast</i> (SSC)–and a dynamic component–the <italic>Dynamic Activity Coefficient</i> (DAC). The SSC is linearly correlated with the relative depth of vessels and is invariant to flow speed, whereas the DAC quantifies blood-flow velocity analogously to classical LSCI and is only weakly depth-dependent. Experiments with phantoms containing a model capillary and flow velocities ranging from 1 to 50 mm/s demonstrate high reproducibility of SSC profiles and a strong correlation between the resulting depth maps and ultrasound tomography (r<sup>2</sup> = 0.90 for transmitted-light detection, r<sup>2</sup> = 0.88 for backscattered-light detection). The suggested approach has been tested <italic>in vivo</i> on a ring finger and has confirmed its high potential for providing non-invasive, contactless, depth-resolved 3D angiography.","PeriodicalId":13094,"journal":{"name":"IEEE Journal of Selected Topics in Quantum Electronics","volume":"32 4: Adv. Biophoton. in Emerg. Biomed. Tech. and Dev","pages":"1-9"},"PeriodicalIF":5.1,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145929604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-22DOI: 10.1109/JSTQE.2025.3647115
Mikhail I. Skvortsov;Kseniya V. Kolosova;Sofia R. Abdullina;Zhibzema E. Munkueva;Alexander V. Dostovalov;Evgeniy V. Podivilov;Sergey A. Babin
The effect of an additional random reflector providing self-injection locking of an erbium fiber DFB laser on linewidth narrowing is studied. In a hybrid cavity comprising a short artificial fs-inscribed random reflector in combination with a natural Rayleigh reflector in the form of 100-m SMF fiber connected to the DFB laser the effect is greatly enhanced. The instantaneous linewidth narrowing by 2 orders is demonstrated which is in approximate agreement with theoretical estimation. For the long-term linewidth, the narrowing of approximately 3 orders of magnitude is observed. Thus, a compact and stable single-frequency laser with quite narrow linewidth (<5 Hz long term) for a wide range of application has been developed.
研究了铒光纤DFB激光器中提供自注入锁定的附加随机反射器对线宽变窄的影响。在混合腔中，由短的人造fs随机反射器与自然瑞利反射器（以100 m SMF光纤的形式连接到DFB激光器）组成的混合腔中，效果大大增强。结果表明，瞬时线宽缩小了2个数量级，与理论估计基本一致。对于长期线宽，观察到大约3个数量级的缩小。因此，一种紧凑和稳定的单频激光器，具有相当窄的线宽（<5赫兹长期），广泛的应用已经开发出来。
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Pub Date : 2025-12-15DOI: 10.1109/JSTQE.2025.3644635
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