Pub Date : 2026-10-19DOI: 10.1021/acsphotonics.6c00025
Luis Felipe Morales Curiel,Aaron Kreis,Michael Krieg
Bioluminescence microscopy offers a uniquely noninvasive window into cellular dynamics, but its use has traditionally been limited by the intrinsically low brightness of luciferases. Their poor photon budget requires long exposure times, preventing faithful visualization of rapid physiological processes, especially in three dimensions. To overcome this barrier, we developed a Fourier light field microscope coupled with deep-learning-based reconstruction that achieves subsecond volumetric bioluminescence imaging, enabling direct recovery of 3D volumes from photon-limited measurements while suppressing reconstruction noise. This approach substantially mitigates the speed–resolution trade-off of conventional light field methods and bypasses the need for slow classical deconvolution priors on the depth-dependent point-spread function. We evaluate its performance by imaging 3D calcium activity in muscles and neurons of freely moving Caenorhabditis elegans and by quantifying cell dynamics within stem-cell-derived spheroids using fluorescenti acquired with fluorescence and bioluminescence contrast. Together, these results establish our framework as a practical tool for dynamic, volumetric studies of living systems.
{"title":"Seeing in the Dark: Intelligent Fourier Light Field Imaging for Bioluminescence Microscopy","authors":"Luis Felipe Morales Curiel,Aaron Kreis,Michael Krieg","doi":"10.1021/acsphotonics.6c00025","DOIUrl":"https://doi.org/10.1021/acsphotonics.6c00025","url":null,"abstract":"Bioluminescence microscopy offers a uniquely noninvasive window into cellular dynamics, but its use has traditionally been limited by the intrinsically low brightness of luciferases. Their poor photon budget requires long exposure times, preventing faithful visualization of rapid physiological processes, especially in three dimensions. To overcome this barrier, we developed a Fourier light field microscope coupled with deep-learning-based reconstruction that achieves subsecond volumetric bioluminescence imaging, enabling direct recovery of 3D volumes from photon-limited measurements while suppressing reconstruction noise. This approach substantially mitigates the speed–resolution trade-off of conventional light field methods and bypasses the need for slow classical deconvolution priors on the depth-dependent point-spread function. We evaluate its performance by imaging 3D calcium activity in muscles and neurons of freely moving Caenorhabditis elegans and by quantifying cell dynamics within stem-cell-derived spheroids using fluorescenti acquired with fluorescence and bioluminescence contrast. Together, these results establish our framework as a practical tool for dynamic, volumetric studies of living systems.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"22 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2026-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149218877","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}
Pub Date : 2026-10-19DOI: 10.1021/acsphotonics.6c01763
Wei Wang,Yushi Wang,Chenxing Liu,Zhengyuan Wu,Xin Dong,Kelvin H. L. Zhang,Ning Jia,Qinglin Sai,Hongji Qi,Daoyou Guo,Shan Li,Weihua Tang,Zhilai Fang
High-speed and reliable secure optical communication remains challenging because existing bipolar photodetectors either rely on slow electrochemical processes or require wavelength-selective excitation, resulting in limited processing speed, increased system complexity, and reduced communication reliability. Here, we demonstrate a gate-programmable solar-blind β-Ga2O3 phototransistor, in which gate-controlled reconfiguration of lateral and vertical carrier transport enables reversible switching of current polarity under only a fixed 254 nm solar-blind illumination wavelength. The device exhibits a responsivity of 1.73 × 104 A/W, a detectivity above 1014 Jones, and a millisecond response time, outperforming most previously reported photoelectrochemical-type and solid-state bipolar photodetectors in terms of combined sensitivity, speed, and operational simplicity. Benefiting from the electrically programmable bipolar response, the phototransistor further realizes fast XOR logic functionality, enabling encrypted text communication and image encryption/decryption under solar-blind ultraviolet illumination. This work establishes a high-performance β-Ga2O3 optoelectronic platform integrating solar-blind photodetection, logic operation, and information security, providing a promising hardware solution for next-generation secure optical communication systems.
高速可靠的安全光通信仍然具有挑战性，因为现有的双极光电探测器要么依赖于缓慢的电化学过程，要么需要波长选择性激发，导致处理速度有限，系统复杂性增加，通信可靠性降低。在这里，我们展示了一个栅极可编程的太阳盲β-Ga2O3光电晶体管，其中栅极控制的横向和垂直载流子输运的重新配置可以在固定的254 nm太阳盲照明波长下实现电流极性的可逆切换。该器件的响应率为1.73 × 104 a /W，探测率高于1014 Jones，响应时间为毫秒，在综合灵敏度、速度和操作简单性方面优于大多数先前报道的光电化学型和固态双极光电探测器。得益于电可编程双极响应，光电晶体管进一步实现了快速异或逻辑功能，实现了在太阳盲紫外线照射下的加密文本通信和图像加密/解密。本工作建立了集日盲光探测、逻辑运算和信息安全于一体的高性能β-Ga2O3光电平台，为下一代安全光通信系统提供了一个有前景的硬件解决方案。
{"title":"Gate-Programmable Bipolar β-Ga2O3 Solar-Blind Phototransistor for Encrypted Optical Communication and Image Transmission","authors":"Wei Wang,Yushi Wang,Chenxing Liu,Zhengyuan Wu,Xin Dong,Kelvin H. L. Zhang,Ning Jia,Qinglin Sai,Hongji Qi,Daoyou Guo,Shan Li,Weihua Tang,Zhilai Fang","doi":"10.1021/acsphotonics.6c01763","DOIUrl":"https://doi.org/10.1021/acsphotonics.6c01763","url":null,"abstract":"High-speed and reliable secure optical communication remains challenging because existing bipolar photodetectors either rely on slow electrochemical processes or require wavelength-selective excitation, resulting in limited processing speed, increased system complexity, and reduced communication reliability. Here, we demonstrate a gate-programmable solar-blind β-Ga2O3 phototransistor, in which gate-controlled reconfiguration of lateral and vertical carrier transport enables reversible switching of current polarity under only a fixed 254 nm solar-blind illumination wavelength. The device exhibits a responsivity of 1.73 × 104 A/W, a detectivity above 1014 Jones, and a millisecond response time, outperforming most previously reported photoelectrochemical-type and solid-state bipolar photodetectors in terms of combined sensitivity, speed, and operational simplicity. Benefiting from the electrically programmable bipolar response, the phototransistor further realizes fast XOR logic functionality, enabling encrypted text communication and image encryption/decryption under solar-blind ultraviolet illumination. This work establishes a high-performance β-Ga2O3 optoelectronic platform integrating solar-blind photodetection, logic operation, and information security, providing a promising hardware solution for next-generation secure optical communication systems.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"25 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2026-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149218824","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}
Disordered coatings based on silica microspheres provide a scalable and robust platform for passive daytime radiative cooling. While particle-size optimization is often considered critical for enhancing solar scattering, the role of microsphere diameter once a coating operates in the multiple-scattering regime remains unclear. Here, we characterize the radiative cooling performance of disordered, multiply scattering photonic glass coatings with diameters ranging from 2 to 8 μm, deposited on a highly reflective substrate. Despite measurable differences in microscopic scattering properties, both the spectral radiative response and the net cooling performance are robust to variations in particle diameter within the investigated range. Outdoor thermal measurements reveal nearly identical steady-state temperature reductions across the full size range. These results identify this robustness as a property of the complete coating–substrate architecture: in the solar range, multiple scattering and the reflective substrate act together to maintain high reflectance, while in the mid-infrared range, the response is dominated by the intrinsic Si–O absorption of the silica layer. This robustness enables microsphere size to be selected based on surface chemistry or processing constraints without compromising cooling performance.
{"title":"Robust Radiative Cooling in Functionalizable Silica Microsphere Paints","authors":"Jorge Burgos,José Rodrigo Magana,Ares Lladós,Javier Pascualena Ferré,Sara Núñez-Sánchez,Juliana Jaramillo Fernández,Cefe López,Pedro David García","doi":"10.1021/acsphotonics.6c01355","DOIUrl":"https://doi.org/10.1021/acsphotonics.6c01355","url":null,"abstract":"Disordered coatings based on silica microspheres provide a scalable and robust platform for passive daytime radiative cooling. While particle-size optimization is often considered critical for enhancing solar scattering, the role of microsphere diameter once a coating operates in the multiple-scattering regime remains unclear. Here, we characterize the radiative cooling performance of disordered, multiply scattering photonic glass coatings with diameters ranging from 2 to 8 μm, deposited on a highly reflective substrate. Despite measurable differences in microscopic scattering properties, both the spectral radiative response and the net cooling performance are robust to variations in particle diameter within the investigated range. Outdoor thermal measurements reveal nearly identical steady-state temperature reductions across the full size range. These results identify this robustness as a property of the complete coating–substrate architecture: in the solar range, multiple scattering and the reflective substrate act together to maintain high reflectance, while in the mid-infrared range, the response is dominated by the intrinsic Si–O absorption of the silica layer. This robustness enables microsphere size to be selected based on surface chemistry or processing constraints without compromising cooling performance.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"81 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2026-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149210864","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}
Pub Date : 2026-10-17DOI: 10.1021/acsphotonics.6c01729
Alexander Neuhaus,Pascal Dreher,Philipp Gessler,Bettina Frank,Timothy J. Davis,Harald Giessen,Karin Everschor-Sitte,Frank-J. Meyer zu Heringdorf
Abstract Topological concepts are frequently used to describe structured optical fields, including plasmonic near fields. Topological descriptions in terms of skyrmion numbers implicitly assume the compactness of the underlying manifold. While this concept works for constrained fields due to inherent integration boundaries, compactness is usually not fulfilled in extended optical fields. Here, we use time-resolved polarimetric photoemission microscopy to determine the electric field vectors of a surface plasmon polariton nanofocus on Au(111) with deep sub-wavelength spatial and sub-fs temporal resolution. The surface plasmon polaritons were excited with circularly polarized light at an Archimedean spiral that was milled into the Au surface by a focused ion beam. The full vectorial field information provided by polarimetric PEEM allows for a spatiotemporal analysis of the skyrmion number of the field texture. At a fixed time, the skyrmion number oscillates as a function of the radius. Furthermore, the skyrmion number oscillates in time. The experimental findings are compared to analytical calculations that lead to the same conclusion: a global skyrmion number cannot be assigned in such non-compact fields. Our results reveal the limitations of the skyrmion number for optical fields and motivate the search for new topological invariants suited for optical fields.
{"title":"Analysis of\u0000the Topology of a Plasmonic Target-Skyrmion\u0000Texture","authors":"Alexander Neuhaus,Pascal Dreher,Philipp Gessler,Bettina Frank,Timothy J. Davis,Harald Giessen,Karin Everschor-Sitte,Frank-J. Meyer zu Heringdorf","doi":"10.1021/acsphotonics.6c01729","DOIUrl":"https://doi.org/10.1021/acsphotonics.6c01729","url":null,"abstract":"Abstract Topological concepts are frequently used to describe structured optical fields, including plasmonic near fields. Topological descriptions in terms of skyrmion numbers implicitly assume the compactness of the underlying manifold. While this concept works for constrained fields due to inherent integration boundaries, compactness is usually not fulfilled in extended optical fields. Here, we use time-resolved polarimetric photoemission microscopy to determine the electric field vectors of a surface plasmon polariton nanofocus on Au(111) with deep sub-wavelength spatial and sub-fs temporal resolution. The surface plasmon polaritons were excited with circularly polarized light at an Archimedean spiral that was milled into the Au surface by a focused ion beam. The full vectorial field information provided by polarimetric PEEM allows for a spatiotemporal analysis of the skyrmion number of the field texture. At a fixed time, the skyrmion number oscillates as a function of the radius. Furthermore, the skyrmion number oscillates in time. The experimental findings are compared to analytical calculations that lead to the same conclusion: a global skyrmion number cannot be assigned in such non-compact fields. Our results reveal the limitations of the skyrmion number for optical fields and motivate the search for new topological invariants suited for optical fields.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"1 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2026-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149210031","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}
Pub Date : 2026-10-16DOI: 10.1021/acsphotonics.6c01318
Johannes Bürger,Erika Cortese,Simone Di Muzio,Daniele Sanvitto,Simone De Liberato,Dario Ballarini
Abstract Strong light–matter coupling in optical waveguides provides a versatile platform for engineering hybrid polaritonic modes and their dispersion. Here, we investigate multimode exciton–photon coupling in visible semiconductor waveguides supporting several transverse electric modes. Using rigorous coupled-wave analysis combined with a coupled-oscillator model, we show that the photonic band structure can be engineered across a range of regimes, from conventional multimode strong coupling to the superstrong coupling regime, where the Rabi coupling becomes comparable to the spacing between adjacent photonic modes. In the latter regime, hybridization between orthogonal electromagnetic modes is enabled by restricting the active material to a subregion of the mode volume where the photonic modes exhibit strong mutual overlap. This breaking of the orthogonality leads to polaritonic branches whose composition can be tuned among several photonic modes and the exciton. We demonstrate that small shifts of the exciton resonance produce pronounced changes in the propagation constants of different polariton branches, enabling exciton-controlled phase modulation through modal interference and, in the superstrong coupling regime, direct modal switching across a continuous S-shaped dispersion. The resulting figures of merit predict π phase shifts for exciton energy shifts of only a few meV over propagation lengths of tens of micrometers, while larger shifts are still required for mode switching. These results establish multimode waveguide polaritons as a versatile platform spanning multiple coupling regimes, for compact phase and intensity control in integrated photonic architectures.
{"title":"Exciton-Tunable\u0000Phase Control and Superstrong Coupling\u0000through Multimode Polariton Engineering in Planar Waveguides","authors":"Johannes Bürger,Erika Cortese,Simone Di Muzio,Daniele Sanvitto,Simone De Liberato,Dario Ballarini","doi":"10.1021/acsphotonics.6c01318","DOIUrl":"https://doi.org/10.1021/acsphotonics.6c01318","url":null,"abstract":"Abstract Strong light–matter coupling in optical waveguides provides a versatile platform for engineering hybrid polaritonic modes and their dispersion. Here, we investigate multimode exciton–photon coupling in visible semiconductor waveguides supporting several transverse electric modes. Using rigorous coupled-wave analysis combined with a coupled-oscillator model, we show that the photonic band structure can be engineered across a range of regimes, from conventional multimode strong coupling to the superstrong coupling regime, where the Rabi coupling becomes comparable to the spacing between adjacent photonic modes. In the latter regime, hybridization between orthogonal electromagnetic modes is enabled by restricting the active material to a subregion of the mode volume where the photonic modes exhibit strong mutual overlap. This breaking of the orthogonality leads to polaritonic branches whose composition can be tuned among several photonic modes and the exciton. We demonstrate that small shifts of the exciton resonance produce pronounced changes in the propagation constants of different polariton branches, enabling exciton-controlled phase modulation through modal interference and, in the superstrong coupling regime, direct modal switching across a continuous S-shaped dispersion. The resulting figures of merit predict π phase shifts for exciton energy shifts of only a few meV over propagation lengths of tens of micrometers, while larger shifts are still required for mode switching. These results establish multimode waveguide polaritons as a versatile platform spanning multiple coupling regimes, for compact phase and intensity control in integrated photonic architectures.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"482 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2026-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149210032","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}
Pub Date : 2026-10-15DOI: 10.1021/acsphotonics.6c01984
Tanvir M. Mahim,Md Nahin Islam,M. Mosaddequr Rahman,Abu S. M. Mohsin
Abstract Identifying which candidate sites on a solid-state sample are single-photon emitters requires a Hanbury Brown–Twiss (HBT) measurement of the second-order correlation function g(2)(τ), which is slow because photon coincidences accumulate at a rate proportional to the square of the detected count rate. We examine how much of this time can be saved by deciding while the coincidences are still accumulating and by adapting the exposure of each site. A spiking neural network reads the coincidence record in short time slices and updates, after every slice, its estimate of the probability that the site hosts a single emitter; a reinforcement-learning controller decides, site by site, whether to expose longer, certify, or reject; and a graph that encodes the electronic level structure of each emitter class conditions one estimator on the class being measured. All components are trained on simulated data from a standard three-level photon-counting model, which we validate against the exact master-equation solution before use. In simulation, the event-driven estimator reaches 90% balanced accuracy with 6 times less acquisition time than a multistart least-squares fit, typically committing to a decision 312 ms into a 1 s exposure, and adaptive exposure screens simulated 48-site fields 1.7 times faster than fixed-dwell scanning at matched precision and recall. Applied without retraining to published experimental HBT data from an InGaAs/GaAs quantum dot, a network trained only on simulated pulsed-excitation histograms estimates g(2)(0) from 30 s records with half the error of peak-area analysis of the same records. The closed-loop results are obtained in simulation only. The code, data, and trained models are openly available.
{"title":"Closed-Loop,\u0000Event-Driven Machine Learning for Autonomous\u0000Triage of Single-Photon Emitters","authors":"Tanvir M. Mahim,Md Nahin Islam,M. Mosaddequr Rahman,Abu S. M. Mohsin","doi":"10.1021/acsphotonics.6c01984","DOIUrl":"https://doi.org/10.1021/acsphotonics.6c01984","url":null,"abstract":"Abstract Identifying which candidate sites on a solid-state sample are single-photon emitters requires a Hanbury Brown–Twiss (HBT) measurement of the second-order correlation function g(2)(τ), which is slow because photon coincidences accumulate at a rate proportional to the square of the detected count rate. We examine how much of this time can be saved by deciding while the coincidences are still accumulating and by adapting the exposure of each site. A spiking neural network reads the coincidence record in short time slices and updates, after every slice, its estimate of the probability that the site hosts a single emitter; a reinforcement-learning controller decides, site by site, whether to expose longer, certify, or reject; and a graph that encodes the electronic level structure of each emitter class conditions one estimator on the class being measured. All components are trained on simulated data from a standard three-level photon-counting model, which we validate against the exact master-equation solution before use. In simulation, the event-driven estimator reaches 90% balanced accuracy with 6 times less acquisition time than a multistart least-squares fit, typically committing to a decision 312 ms into a 1 s exposure, and adaptive exposure screens simulated 48-site fields 1.7 times faster than fixed-dwell scanning at matched precision and recall. Applied without retraining to published experimental HBT data from an InGaAs/GaAs quantum dot, a network trained only on simulated pulsed-excitation histograms estimates g(2)(0) from 30 s records with half the error of peak-area analysis of the same records. The closed-loop results are obtained in simulation only. The code, data, and trained models are openly available.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"20 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149210036","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}
Pub Date : 2026-10-15DOI: 10.1021/acsphotonics.6c01684
Emmanuel Kotu Robertson,Dennis van de Lockand,Matz Liebel
Abstract Mid-infrared photothermal microscopy combines the chemical specificity of infrared absorption with the spatial resolution of visible light detection, but practical implementations face a persistent trade-off between forward-scattering (FWS) and backward-scattering (BWS) detection geometries. FWS provides quantitative, shape-independent phase contrast but requires two-sided optical access, which is difficult to achieve in aqueous or thick samples. BWS offers convenient single-sided access, but its signals are strongly distorted by depth-dependent interference for micrometer-scale objects. Here, we present a bidirectional femtosecond mid-infrared pump–probe holographic microscope capable of switching between FWS and BWS geometries within a single instrument and use it to introduce and validate a new imaging modality, internal forward scattering (IFS). IFS exploits the back reflection generated at the top surface of the mid-infrared-transparent sample substrate as an internally generated forward-scattering illumination wave, isolated from the directly backscattered field via temporal coherence gating. Using polystyrene beads on CaF2 substrates in air, water, and a refractive-index-matched glycerol–water mixture, we show that IFS reproduces the signal magnitudes and temporal dynamics of true FWS measurements while retaining the mechanical simplicity and single-sided accessibility of BWS. These results establish IFS as a practical, quantitative alternative to conventional FWS and BWS geometries for photothermal and, more broadly, quantitative phase imaging, with direct relevance to single-sided imaging of biological or solvent-contained specimens.
{"title":"Bidirectional\u0000Phase Sensitivity in Holographic Phototransient\u0000Microscopy","authors":"Emmanuel Kotu Robertson,Dennis van de Lockand,Matz Liebel","doi":"10.1021/acsphotonics.6c01684","DOIUrl":"https://doi.org/10.1021/acsphotonics.6c01684","url":null,"abstract":"Abstract Mid-infrared photothermal microscopy combines the chemical specificity of infrared absorption with the spatial resolution of visible light detection, but practical implementations face a persistent trade-off between forward-scattering (FWS) and backward-scattering (BWS) detection geometries. FWS provides quantitative, shape-independent phase contrast but requires two-sided optical access, which is difficult to achieve in aqueous or thick samples. BWS offers convenient single-sided access, but its signals are strongly distorted by depth-dependent interference for micrometer-scale objects. Here, we present a bidirectional femtosecond mid-infrared pump–probe holographic microscope capable of switching between FWS and BWS geometries within a single instrument and use it to introduce and validate a new imaging modality, internal forward scattering (IFS). IFS exploits the back reflection generated at the top surface of the mid-infrared-transparent sample substrate as an internally generated forward-scattering illumination wave, isolated from the directly backscattered field via temporal coherence gating. Using polystyrene beads on CaF2 substrates in air, water, and a refractive-index-matched glycerol–water mixture, we show that IFS reproduces the signal magnitudes and temporal dynamics of true FWS measurements while retaining the mechanical simplicity and single-sided accessibility of BWS. These results establish IFS as a practical, quantitative alternative to conventional FWS and BWS geometries for photothermal and, more broadly, quantitative phase imaging, with direct relevance to single-sided imaging of biological or solvent-contained specimens.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"64 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149210033","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}
Abstract The escalating demand for data traffic is driving the pursuit of new wavelength bands beyond the conventional telecom windows as a key expansion strategy. The 2 μm waveband is considered a novel communication window with distinct advantages of lower signal loss and broader gain bandwidth. Meanwhile, wavelength conversion is a critical enabler for the next-generation high-speed all-optical networks. In this work, we demonstrate, for the first time, all-optical wavelength conversion of high-speed nonreturn-to-zero on–off keying signals in the 2 μm waveband via four-wave mixing, employing a continuous-wave pump and silicon waveguides fabricated on a standard 340 nm silicon-on-insulator platform. A high conversion efficiency of −12.09 dB is achieved with an input pump power of 21.72 dBm. Facilitated by a pump laser centered at 2008 nm, broadband wavelength conversion is experimentally demonstrated over a conversion span of 314.9 nm. Moreover, wavelength conversion of 10 Gbit/s and 15 Gbit/s data signals is successfully demonstrated, with respective power penalties of 2.56 and 3.95 dB measured at a bit error ratio of 3.8 × 10–3. The promise of the demonstrated mid-infrared wavelength converter for future chip-scale high-speed optical communication is supported by the experimental results.
{"title":"Mid-Infrared\u0000All-Optical Wavelength Conversion of\u0000NRZ OOK Signal in Silicon Waveguides","authors":"Zhiwei Yan,Chang Chang,Xuchen Peng,Guanglian Cheng,Qiyuan Yi,Xinzhe Xiong,Qiyuan Li,Zengfan Shen,Shuang Zheng,Yi Zou,Minming Zhang,Li Shen","doi":"10.1021/acsphotonics.6c00289","DOIUrl":"https://doi.org/10.1021/acsphotonics.6c00289","url":null,"abstract":"Abstract The escalating demand for data traffic is driving the pursuit of new wavelength bands beyond the conventional telecom windows as a key expansion strategy. The 2 μm waveband is considered a novel communication window with distinct advantages of lower signal loss and broader gain bandwidth. Meanwhile, wavelength conversion is a critical enabler for the next-generation high-speed all-optical networks. In this work, we demonstrate, for the first time, all-optical wavelength conversion of high-speed nonreturn-to-zero on–off keying signals in the 2 μm waveband via four-wave mixing, employing a continuous-wave pump and silicon waveguides fabricated on a standard 340 nm silicon-on-insulator platform. A high conversion efficiency of −12.09 dB is achieved with an input pump power of 21.72 dBm. Facilitated by a pump laser centered at 2008 nm, broadband wavelength conversion is experimentally demonstrated over a conversion span of 314.9 nm. Moreover, wavelength conversion of 10 Gbit/s and 15 Gbit/s data signals is successfully demonstrated, with respective power penalties of 2.56 and 3.95 dB measured at a bit error ratio of 3.8 × 10–3. The promise of the demonstrated mid-infrared wavelength converter for future chip-scale high-speed optical communication is supported by the experimental results.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"29 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149210035","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}
Pub Date : 2026-10-15DOI: 10.1021/acsphotonics.6c01818
Shenghan Qin,Peirui Ji,Wenbo Hu,Hanjin Dong,Weihao Tao,Guofeng Zhang,Shuming Yang
Abstract Image sensor arrays built from two-dimensional (2D) materials are emerging as enablers of next-generation optoelectronic systems, yet their development has been constrained by the lack of readout architectures specifically tailored to atomically thin channels. Here, we demonstrate an 8 × 8 monolithic array of monolayer graphene/silicon dioxide/silicon (Gr/SiO2/Si) metal-insulator-semiconductor (MIS) photodetector that employs a row–column addressable scheme, drastically reducing the required interconnects from 64 to only 16. By inserting a silicon dioxide dielectric layer between graphene and silicon, the dark current is suppressed by 3 orders of magnitude, and the highest specific detectivity measured among the devices reaches 1.076 × 1011 cm Hz1/2 W–1. All 64 pixels exhibit uniform photoresponse across the visible to near-infrared spectral range. Using mask-projection imaging, we faithfully reconstruct alphabetic optical patterns, confirming the array’s imaging fidelity. This work holds promise for the development of various types of two-dimensional material-based array devices.
由二维（2D）材料构建的图像传感器阵列正在成为下一代光电系统的推动者，但它们的发展受到缺乏专门为原子薄通道量身定制的读出架构的限制。在这里，我们展示了一个8 × 8单层石墨烯/二氧化硅/硅（Gr/SiO2/Si）金属-绝缘体-半导体（MIS）光电探测器的单片阵列，采用行-列可寻址方案，将所需的互连从64个大幅减少到16个。通过在石墨烯和硅之间插入二氧化硅介电层，暗电流被抑制了3个数量级，器件的最高比探测率达到1.076 × 1011 cm Hz1/2 W-1。所有64个像素在可见光到近红外光谱范围内表现出均匀的光响应。利用掩模投影成像，我们忠实地重建了字母光学模式，证实了阵列的成像保真度。这项工作为开发各种类型的二维材料阵列设备提供了希望。
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Abstract Defect centers in gallium nitride (GaN) emerge as bright sources of single photons, which recently have been demonstrated to optically interface a localized spin. However, the structure and composition of these defects as well as their efficient excitation techniques have not been a subject of thorough studies. This work presents evidence that by tuning the excitation laser energy to specific resonance values, the excitation efficiency can be enhanced, resulting in a relative increase of photoluminescence intensity by up to an order of magnitude. The resonances can be selectively addressed with linearly polarized light, while the emission dipoles remain unchanged, enabling polarization-controlled enhancement. These results establish an efficient method of excitation for GaN-based emitters, thereby increasing the generation rate of photons. The data are consistent with excitation via localized vibrational modes (LVMs) associated with point-defect complexes, establishing a practical quasi-resonant route to brighter, polarization-addressable operation of GaN defect emitters and clarifying their energy-level structure.
{"title":"Efficient Quasi-Resonant,\u0000Polarization-Selective Excitation\u0000of GaN Quantum Emitters","authors":"Nilesh Dalla,Paweł Kulboka,Michał Kobecki,Jan Misiak,Paweł Prystawko,Tomasz Kazimierczuk,Piotr Kossacki,Henryk Turski,Tomasz Jakubczyk","doi":"10.1021/acsphotonics.6c02170","DOIUrl":"https://doi.org/10.1021/acsphotonics.6c02170","url":null,"abstract":"Abstract Defect centers in gallium nitride (GaN) emerge as bright sources of single photons, which recently have been demonstrated to optically interface a localized spin. However, the structure and composition of these defects as well as their efficient excitation techniques have not been a subject of thorough studies. This work presents evidence that by tuning the excitation laser energy to specific resonance values, the excitation efficiency can be enhanced, resulting in a relative increase of photoluminescence intensity by up to an order of magnitude. The resonances can be selectively addressed with linearly polarized light, while the emission dipoles remain unchanged, enabling polarization-controlled enhancement. These results establish an efficient method of excitation for GaN-based emitters, thereby increasing the generation rate of photons. The data are consistent with excitation via localized vibrational modes (LVMs) associated with point-defect complexes, establishing a practical quasi-resonant route to brighter, polarization-addressable operation of GaN defect emitters and clarifying their energy-level structure.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"32 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149210474","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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