Pub Date : 2025-02-17DOI: 10.1021/acsphotonics.4c02359
Diana Dall’Aglio, Guillermo D. Brinatti Vazquez, Luca Bolzonello, Iris Cusini, Robin Camphausen, Niek F. van Hulst
Spatiotemporal microscopy plays an important role in the quest for highly efficient light harvesting materials as it allows direct tracking of the nanoscale transport of excitons, the carriers of the photon energy. Unfortunately, achieving high resolution in both space and time often requires scanning beam spots or delay lines, limiting these techniques to specialized research groups. To overcome this problem, we introduce a novel implementation of photoluminescence-detected exciton tracking using a camera composed of an array of single-photon avalanche diodes (SPADs), gated with ∼150 ps temporal accuracy. The use of such a SPAD camera drastically simplifies the experiment, is free of moving parts, and provides at least 1 order of magnitude increase in photon collection efficiency due to the parallel multipixel acquisition. Moreover, the camera allows one to implement different super-resolution excitation strategies. Here we show both point and structured excitation in the same device by simply changing the optical element. The structured illumination allows direct retrieval of the diffusion from a single time-resolved imaging without fitting, even at fluences far below exciton–exciton annihilation conditions. We tested the SPAD camera effectiveness by studying the exciton diffusion properties of the organic photovoltaic material PM6, where we measured an exciton diffusion length of 45 nm. Certainly our new implementation, boosted by rapid advances in SPAD technology, will extend the range of both users and applications of spatiotemporal microscopy.
{"title":"Spatiotemporal Exciton Tracking with a SPAD Camera","authors":"Diana Dall’Aglio, Guillermo D. Brinatti Vazquez, Luca Bolzonello, Iris Cusini, Robin Camphausen, Niek F. van Hulst","doi":"10.1021/acsphotonics.4c02359","DOIUrl":"https://doi.org/10.1021/acsphotonics.4c02359","url":null,"abstract":"Spatiotemporal microscopy plays an important role in the quest for highly efficient light harvesting materials as it allows direct tracking of the nanoscale transport of excitons, the carriers of the photon energy. Unfortunately, achieving high resolution in both space and time often requires scanning beam spots or delay lines, limiting these techniques to specialized research groups. To overcome this problem, we introduce a novel implementation of photoluminescence-detected exciton tracking using a camera composed of an array of single-photon avalanche diodes (SPADs), gated with ∼150 ps temporal accuracy. The use of such a SPAD camera drastically simplifies the experiment, is free of moving parts, and provides at least 1 order of magnitude increase in photon collection efficiency due to the parallel multipixel acquisition. Moreover, the camera allows one to implement different super-resolution excitation strategies. Here we show both point and structured excitation in the same device by simply changing the optical element. The structured illumination allows direct retrieval of the diffusion from a single time-resolved imaging without fitting, even at fluences far below exciton–exciton annihilation conditions. We tested the SPAD camera effectiveness by studying the exciton diffusion properties of the organic photovoltaic material PM6, where we measured an exciton diffusion length of 45 nm. Certainly our new implementation, boosted by rapid advances in SPAD technology, will extend the range of both users and applications of spatiotemporal microscopy.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"14 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427058","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 : 2025-02-17DOI: 10.1021/acsphotonics.4c01657
Ediz Kaan Herkert, Maria F. Garcia-Parajo
Plasmonic nanostructures exhibit localized surface plasmon resonances due to collective oscillation of conducting electrons that can be tuned by modulating the nanostructure size, shape, material composition, and local dielectric environment. The strong field confinement and enhancement provided by plasmonic nanostructures have been exploited over the years to enhance the sensitivity for analyte detection down to the single-molecule level, rendering these devices as potentially outstanding biosensors. Here, we summarize methods to detect biological analytes in vitro and in living cells, with a focus on plasmon-enhanced fluorescence, Raman scattering, infrared absorption, circular dichroism, and refractive index sensing. Given the tremendous advances in the field, we concentrate on a few recent examples toward biosensing under highly challenging detection conditions, including clinically relevant biomarkers in body fluids and nascent applications in living cells and in vivo. These emerging platforms serve as inspiration for exploring future directions of nanoplasmonics that can be further harnessed to advance real-world biosensing applications.
{"title":"Harnessing the Power of Plasmonics for in Vitro and in Vivo Biosensing","authors":"Ediz Kaan Herkert, Maria F. Garcia-Parajo","doi":"10.1021/acsphotonics.4c01657","DOIUrl":"https://doi.org/10.1021/acsphotonics.4c01657","url":null,"abstract":"Plasmonic nanostructures exhibit localized surface plasmon resonances due to collective oscillation of conducting electrons that can be tuned by modulating the nanostructure size, shape, material composition, and local dielectric environment. The strong field confinement and enhancement provided by plasmonic nanostructures have been exploited over the years to enhance the sensitivity for analyte detection down to the single-molecule level, rendering these devices as potentially outstanding biosensors. Here, we summarize methods to detect biological analytes <i>in vitro</i> and <i>in living cells</i>, with a focus on plasmon-enhanced fluorescence, Raman scattering, infrared absorption, circular dichroism, and refractive index sensing. Given the tremendous advances in the field, we concentrate on a few recent examples toward biosensing under highly challenging detection conditions, including clinically relevant biomarkers in body fluids and nascent applications in living cells and <i>in vivo</i>. These emerging platforms serve as inspiration for exploring future directions of nanoplasmonics that can be further harnessed to advance real-world biosensing applications.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"2 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427056","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 : 2025-02-17DOI: 10.1021/acsphotonics.4c02327
Jicai Zhang, Tran Trung Luu
The symmetry of a material is crucial to defining its electronic and structural properties. By manipulating this symmetry through photoinduced phase transitions, one can explore innovative methods for controlling material characteristics on ultrafast time scales. It is essential to employ techniques that can probe symmetrical changes in the temporal domain to capture these transitions. Here, by utilizing time-resolved third-order nonlinear spectroscopy, we demonstrate that a time-domain analysis of the coherent phonon dynamics can effectively reveal alterations in the symmetry of the lattice potential. This nonlinear approach serves as a fully optical method for investigating structural transitions. Focusing on the photoinduced structural phase transition in the α-CaF2 dielectric crystal, we observe that as photoexcited carriers increase, the coherent phonon mode initially exhibits a softening effect. Subsequently, the transition from α-CaF2 to γ-CaF2 occurs at higher carrier density, corresponding to a switch from the high-symmetry Fm3̅m to the low-symmetry Pnma space group. The immediate emergence of equilibrium-phase phonon modes beyond the transition threshold indicates a nonthermal mechanism for the photoinduced symmetry changes, where significant perturbation of the lattice potential alters its symmetry before any ionic rearrangement takes place. Our findings open new avenues for investigating structural transitions on the femtosecond time scale.
{"title":"Probing Photoinduced Structural Phase Transitions via Nonlinear Spectroscopy","authors":"Jicai Zhang, Tran Trung Luu","doi":"10.1021/acsphotonics.4c02327","DOIUrl":"https://doi.org/10.1021/acsphotonics.4c02327","url":null,"abstract":"The symmetry of a material is crucial to defining its electronic and structural properties. By manipulating this symmetry through photoinduced phase transitions, one can explore innovative methods for controlling material characteristics on ultrafast time scales. It is essential to employ techniques that can probe symmetrical changes in the temporal domain to capture these transitions. Here, by utilizing time-resolved third-order nonlinear spectroscopy, we demonstrate that a time-domain analysis of the coherent phonon dynamics can effectively reveal alterations in the symmetry of the lattice potential. This nonlinear approach serves as a fully optical method for investigating structural transitions. Focusing on the photoinduced structural phase transition in the α-CaF<sub>2</sub> dielectric crystal, we observe that as photoexcited carriers increase, the coherent phonon mode initially exhibits a softening effect. Subsequently, the transition from α-CaF<sub>2</sub> to γ-CaF<sub>2</sub> occurs at higher carrier density, corresponding to a switch from the high-symmetry <i>Fm</i>3̅<i>m</i> to the low-symmetry <i>Pnma</i> space group. The immediate emergence of equilibrium-phase phonon modes beyond the transition threshold indicates a nonthermal mechanism for the photoinduced symmetry changes, where significant perturbation of the lattice potential alters its symmetry before any ionic rearrangement takes place. Our findings open new avenues for investigating structural transitions on the femtosecond time scale.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"64 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427057","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 : 2025-02-17DOI: 10.1021/acsphotonics.4c02412
Chenxi Zhang, Runlin Miao, Ke Yin, Xiang’Ai Cheng, Tian Jiang
Soliton microcombs, a pivotal technology supporting various cutting-edge applications from metrology to communications, can be efficiently generated through the pulsed driving of Kerr microresonators. However, the mechanism that influences driving pulses on soliton generation has not been comprehensively explored. Here, we demonstrate a chip-based pulse-driven soliton comb with the minimal on-chip pump power of 1.70 mW at 25 GHz repetition rate and study the impact of pulse chirp numerically and experimentally. By varying pulse chirp and desynchronization, a wide locking range of 900 kHz can be reached with fixed cavity parameters, ensuring efficient attractive single-soliton operation. This work reveals that pulse pumping introduces more degrees of freedom and rich novel dynamics into soliton generation and could facilitate the development of efficient on-chip soliton microcomb systems.
{"title":"Impact of Pulse Chirp and Desynchronization on Chip-Based Pulse-Driven Soliton Microcombs","authors":"Chenxi Zhang, Runlin Miao, Ke Yin, Xiang’Ai Cheng, Tian Jiang","doi":"10.1021/acsphotonics.4c02412","DOIUrl":"https://doi.org/10.1021/acsphotonics.4c02412","url":null,"abstract":"Soliton microcombs, a pivotal technology supporting various cutting-edge applications from metrology to communications, can be efficiently generated through the pulsed driving of Kerr microresonators. However, the mechanism that influences driving pulses on soliton generation has not been comprehensively explored. Here, we demonstrate a chip-based pulse-driven soliton comb with the minimal on-chip pump power of 1.70 mW at 25 GHz repetition rate and study the impact of pulse chirp numerically and experimentally. By varying pulse chirp and desynchronization, a wide locking range of 900 kHz can be reached with fixed cavity parameters, ensuring efficient attractive single-soliton operation. This work reveals that pulse pumping introduces more degrees of freedom and rich novel dynamics into soliton generation and could facilitate the development of efficient on-chip soliton microcomb systems.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"12 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427059","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}
Vortex beams (VBs), with their unique spatial light field distribution, show promising applications in fields such as optical micromanipulation and high-capacity optical communications. However, the simultaneous realization of broad wavelength tunability and high topological charge remains a great challenge. In this work, based on the gain media of fluorescent carbon dots, which are known as a class of solution-processable and biocompatible materials with luminescence spectra covering from ultraviolet to near-infrared, perfect vortex beams (PVBs) with a wide wavelength tunability of up to 15 nm and a high topological charge of up to 50 have been realized for the first time. A combined strategy using double-beam interference pumping and a spatial light modulator (SLM) was proposed. Results show that the radii of the PVBs are independent of the number of topological charges but vary with the laser wavelength. While they can also be flexibly tuned by changing the period of the axicon and the focal length of the Fourier lens. Finally, a polarized PVB was successfully constructed by using a cascaded SLM, which further enriches the vortex mode properties of the carbon dot lasers. The results not only provide a new route for simultaneously improving the wavelength tunability and the topological charge of vortex lasers but also deepen the understanding of the mode properties of carbon dot lasers.
{"title":"Wide Tunable Wavelength, High Topological Charge Perfect Vortex Beams Based on Carbon Dot Lasers","authors":"Qingxiu Song, Xiangdong Wang, Jiuru He, Liwen Cheng, Yongqiang Zhang, Yongsheng Hu, Siyu Lu","doi":"10.1021/acsphotonics.4c02241","DOIUrl":"https://doi.org/10.1021/acsphotonics.4c02241","url":null,"abstract":"Vortex beams (VBs), with their unique spatial light field distribution, show promising applications in fields such as optical micromanipulation and high-capacity optical communications. However, the simultaneous realization of broad wavelength tunability and high topological charge remains a great challenge. In this work, based on the gain media of fluorescent carbon dots, which are known as a class of solution-processable and biocompatible materials with luminescence spectra covering from ultraviolet to near-infrared, perfect vortex beams (PVBs) with a wide wavelength tunability of up to 15 nm and a high topological charge of up to 50 have been realized for the first time. A combined strategy using double-beam interference pumping and a spatial light modulator (SLM) was proposed. Results show that the radii of the PVBs are independent of the number of topological charges but vary with the laser wavelength. While they can also be flexibly tuned by changing the period of the axicon and the focal length of the Fourier lens. Finally, a polarized PVB was successfully constructed by using a cascaded SLM, which further enriches the vortex mode properties of the carbon dot lasers. The results not only provide a new route for simultaneously improving the wavelength tunability and the topological charge of vortex lasers but also deepen the understanding of the mode properties of carbon dot lasers.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"80 4 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427060","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 : 2025-02-15DOI: 10.1021/acsphotonics.4c01999
Neuton Li, Jihua Zhang, Dragomir N. Neshev, Andrey A. Sukhorukov
We demonstrate metasurfaces with strong polarization dichroism that depends on the angle of incidence. We present original designs obtained through topology optimization that selectively transmit specific linear or circular polarizations at different incident angles, while the orthogonal polarization transmission is suppressed. The designed metasurfaces exceed 95% transmission efficiency and 50× extinction ratio within the target angle ranges. The experimental characterization of fabricated metasurfaces confirms the desired operation with 90% transmission efficiency and 10× polarization extinction ratio. These results provide important insights into nonlocal and k-space engineering of metasurface response, and the results reveal new opportunities for future multifunctional and angle-selective polarization devices that can find applications in specialized optical instruments and end-user devices.
{"title":"Angle Multifunctional Dichroism in Metasurfaces","authors":"Neuton Li, Jihua Zhang, Dragomir N. Neshev, Andrey A. Sukhorukov","doi":"10.1021/acsphotonics.4c01999","DOIUrl":"https://doi.org/10.1021/acsphotonics.4c01999","url":null,"abstract":"We demonstrate metasurfaces with strong polarization dichroism that depends on the angle of incidence. We present original designs obtained through topology optimization that selectively transmit specific linear or circular polarizations at different incident angles, while the orthogonal polarization transmission is suppressed. The designed metasurfaces exceed 95% transmission efficiency and 50× extinction ratio within the target angle ranges. The experimental characterization of fabricated metasurfaces confirms the desired operation with 90% transmission efficiency and 10× polarization extinction ratio. These results provide important insights into nonlocal and <i>k</i>-space engineering of metasurface response, and the results reveal new opportunities for future multifunctional and angle-selective polarization devices that can find applications in specialized optical instruments and end-user devices.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"43 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143418250","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 : 2025-02-13DOI: 10.1021/acsphotonics.4c02266
Charles Roques-Carmes, Kai Wang, Yuanmu Yang, Arka Majumdar, Zin Lin
Metasurfaces, ultrathin structures composed of subwavelength optical elements, have revolutionized light manipulation by enabling precise control over electromagnetic waves’ amplitude, phase, polarization, and spectral properties. Concurrently, computational imaging leverages algorithms to reconstruct images from optically processed signals, overcoming the limitations of traditional imaging systems. This Perspective explores the synergistic integration of metaoptics and computational imaging, “metaoptic computational imaging”, which combines the physical wavefront shaping ability of metasurfaces with advanced computational algorithms to enhance imaging performance beyond conventional limits. We discuss how metaoptic computational imaging addresses the inherent limitations of single-layer metasurfaces in achieving multifunctionality without compromising efficiency. By treating metasurfaces as physical preconditioners and codesigning them with reconstruction algorithms through end-to-end (inverse) design, it is possible to jointly optimize the optical hardware and computational software. Advanced applications and new frontiers in the field enabled by metaoptic computational imaging are highlighted, including phase imaging and quantum state measurement.
{"title":"Metaoptic Computational Imaging","authors":"Charles Roques-Carmes, Kai Wang, Yuanmu Yang, Arka Majumdar, Zin Lin","doi":"10.1021/acsphotonics.4c02266","DOIUrl":"https://doi.org/10.1021/acsphotonics.4c02266","url":null,"abstract":"Metasurfaces, ultrathin structures composed of subwavelength optical elements, have revolutionized light manipulation by enabling precise control over electromagnetic waves’ amplitude, phase, polarization, and spectral properties. Concurrently, computational imaging leverages algorithms to reconstruct images from optically processed signals, overcoming the limitations of traditional imaging systems. This Perspective explores the synergistic integration of metaoptics and computational imaging, “metaoptic computational imaging”, which combines the physical wavefront shaping ability of metasurfaces with advanced computational algorithms to enhance imaging performance beyond conventional limits. We discuss how metaoptic computational imaging addresses the inherent limitations of single-layer metasurfaces in achieving multifunctionality without compromising efficiency. By treating metasurfaces as physical preconditioners and codesigning them with reconstruction algorithms through end-to-end (inverse) design, it is possible to jointly optimize the optical hardware and computational software. Advanced applications and new frontiers in the field enabled by metaoptic computational imaging are highlighted, including phase imaging and quantum state measurement.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"1 4 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417925","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 : 2025-02-13DOI: 10.1021/acsphotonics.4c01933
Samuel K. W. Seah, Souvik Biswas, Claudio U. Hail, Min Seok Jang, Harry A. Atwater
The dynamic, on-demand generation of different polarization states of light has diverse applications in optical communications, imaging, sensing, and quantum information processing. Such active polarization control is typically achieved using active metasurfaces or spatial light modulators based on liquid crystal media that have limited switching speeds and conversion efficiency. Layered van der Waals low-dimensional materials provide new avenues for more versatile polarization control with an operating frequency several orders of magnitude higher than that for liquid crystal devices. Here, we report the design of a heterostructure for efficient, polarization-selective free-space phase modulation or amplitude modulation by integrating electrically tunable, optically anisotropic black phosphorus (BP) into high quality factor (Q ∼ 7500 to 11000) distributed Bragg reflector-based Fabry–Perot cavities. These devices achieve a respective phase tuning range of 210° and an amplitude tuning range of 99%. We also introduce designs for BP heterostructures that employ two twisted cross-aligned BP layers that are able to access polarization states covering 75% of the Poincaré sphere from voltage tuning alone. Finally, we introduce a design for an active metasurface polarization beam splitter based on our cavity heterostructures with an electrically tunable angle of diffraction that leverages spatially engineered polarization gradients. These structures open a pathway for further structuring of light by controlling the phase and amplitude along independent orthogonal directions.
按需动态生成不同偏振态的光在光通信、成像、传感和量子信息处理方面有着多种应用。这种主动偏振控制通常使用基于液晶介质的有源元表面或空间光调制器来实现，但其开关速度和转换效率有限。层状范德华低维材料为实现更多功能的偏振控制提供了新途径，其工作频率比液晶器件高出几个数量级。在此，我们报告了一种异质结构的设计，通过将电可调、光学各向异性的黑磷（BP）集成到基于高品质因数（Q ∼ 7500 至 11000）分布式布拉格反射器的法布里-珀罗腔中，实现高效的偏振选择性自由空间相位调制或振幅调制。这些器件的相位调谐范围分别达到 210°，振幅调谐范围达到 99%。我们还介绍了采用两个扭曲交叉排列的 BP 层的 BP 异质结构设计，仅通过电压调谐就能获得覆盖 75% 波恩卡莱球面的偏振态。最后，我们在空腔异质结构的基础上介绍了一种有源元表面偏振分束器的设计，这种分束器具有电可调衍射角，可利用空间工程设计的偏振梯度。这些结构为沿着独立的正交方向控制相位和振幅，进一步构造光的结构开辟了道路。
{"title":"Efficient, Polarization-Diverse State Generation with Tunable Black Phosphorus Cavity Heterostructures and Active Metasurfaces","authors":"Samuel K. W. Seah, Souvik Biswas, Claudio U. Hail, Min Seok Jang, Harry A. Atwater","doi":"10.1021/acsphotonics.4c01933","DOIUrl":"https://doi.org/10.1021/acsphotonics.4c01933","url":null,"abstract":"The dynamic, on-demand generation of different polarization states of light has diverse applications in optical communications, imaging, sensing, and quantum information processing. Such active polarization control is typically achieved using active metasurfaces or spatial light modulators based on liquid crystal media that have limited switching speeds and conversion efficiency. Layered van der Waals low-dimensional materials provide new avenues for more versatile polarization control with an operating frequency several orders of magnitude higher than that for liquid crystal devices. Here, we report the design of a heterostructure for efficient, polarization-selective free-space phase modulation or amplitude modulation by integrating electrically tunable, optically anisotropic black phosphorus (BP) into high quality factor (Q ∼ 7500 to 11000) distributed Bragg reflector-based Fabry–Perot cavities. These devices achieve a respective phase tuning range of 210° and an amplitude tuning range of 99%. We also introduce designs for BP heterostructures that employ two twisted cross-aligned BP layers that are able to access polarization states covering 75% of the Poincaré sphere from voltage tuning alone. Finally, we introduce a design for an active metasurface polarization beam splitter based on our cavity heterostructures with an electrically tunable angle of diffraction that leverages spatially engineered polarization gradients. These structures open a pathway for further structuring of light by controlling the phase and amplitude along independent orthogonal directions.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"16 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417923","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 : 2025-02-12DOI: 10.1021/acsphotonics.4c02081
Thomas W. Radford, Peter R. Wiecha, Alberto Politi, Ioannis Zeimpekis, Otto L. Muskens
The development of low-loss reconfigurable integrated optical devices enables further research into technologies including photonic signal processing, analogue quantum computing, and optical neural networks. Here, we introduce digital patterning of coupled waveguide arrays as a platform capable of implementing unitary matrix operations. Determining the required device geometry for a specific optical output is computationally challenging and requires a robust and versatile inverse design protocol. In this work we present an approach using high speed neural network surrogate-based gradient optimization, capable of predicting patterns of refractive index perturbations based on switching of the ultralow loss chalcogenide phase change material, antimony triselinide (Sb2Se3). Results for a 3 × 3 silicon waveguide array are presented, demonstrating control of both amplitude and phase for each transmission matrix element. Network performance is studied using neural network optimization tools such as data set augmentation and supplementation with random noise, resulting in an average fidelity of 0.94 for unitary matrix targets. Our results show that coupled waveguide arrays with perturbation patterns offer new routes for achieving programmable unitary operators, or Hamiltonians for quantum simulators, with a reduced footprint compared to conventional interferometer-mesh technology.
{"title":"Inverse Design of Unitary Transmission Matrices in Silicon Photonic Coupled Waveguide Arrays Using a Neural Adjoint Model","authors":"Thomas W. Radford, Peter R. Wiecha, Alberto Politi, Ioannis Zeimpekis, Otto L. Muskens","doi":"10.1021/acsphotonics.4c02081","DOIUrl":"https://doi.org/10.1021/acsphotonics.4c02081","url":null,"abstract":"The development of low-loss reconfigurable integrated optical devices enables further research into technologies including photonic signal processing, analogue quantum computing, and optical neural networks. Here, we introduce digital patterning of coupled waveguide arrays as a platform capable of implementing unitary matrix operations. Determining the required device geometry for a specific optical output is computationally challenging and requires a robust and versatile inverse design protocol. In this work we present an approach using high speed neural network surrogate-based gradient optimization, capable of predicting patterns of refractive index perturbations based on switching of the ultralow loss chalcogenide phase change material, antimony triselinide (Sb<sub>2</sub>Se<sub>3</sub>). Results for a 3 × 3 silicon waveguide array are presented, demonstrating control of both amplitude and phase for each transmission matrix element. Network performance is studied using neural network optimization tools such as data set augmentation and supplementation with random noise, resulting in an average fidelity of 0.94 for unitary matrix targets. Our results show that coupled waveguide arrays with perturbation patterns offer new routes for achieving programmable unitary operators, or Hamiltonians for quantum simulators, with a reduced footprint compared to conventional interferometer-mesh technology.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"41 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394007","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 : 2025-02-12DOI: 10.1021/acsphotonics.4c02467
Feng Lu, Jian-Peng Dou, Hao Tang, Xiao-Yun Xu, Chao-Ni Zhang, Wen-Hao Zhou, Hong Sun, Xian-Min Jin
Decision-making enables artificial intelligence to dynamically adjust and acquire knowledge from experiences, distinguishing it from traditional computing intelligence based on predetermined and rigid logic rules. However, the hardness of decision-making within the Turing framework increases exponentially with the number of decisions and decision-agents, thereby limiting the speed and scaling for artificial intelligence to process intensity-heavy tasks. Here, by introducing the quantum advantages of both photons and atoms, we report a photon-atom hybrid decision framework, whose decision-making exploration is accomplished through time-correlated atomic excitation within a quantum memory material. We develop a pseudophotonic blockade effect within memory materials to ensure that decision-making conflicts are hardly generated. With exploring a two-agent N-armed bandit in a concurrent manner, an N2 times acceleration of decision-making exploration compared to nonconcurrent methods is demonstrated. Furthermore, the experimentally characterized performance in preference satisfaction and conflict avoidance shows an advanced capacity for distributed decision-making on a significant scale. Our research advances scalable distributed frameworks to address future reinforcement learning challenges.
{"title":"Photon-Atom Hybrid Decision-Framework with Concurrent Exploration Acceleration","authors":"Feng Lu, Jian-Peng Dou, Hao Tang, Xiao-Yun Xu, Chao-Ni Zhang, Wen-Hao Zhou, Hong Sun, Xian-Min Jin","doi":"10.1021/acsphotonics.4c02467","DOIUrl":"https://doi.org/10.1021/acsphotonics.4c02467","url":null,"abstract":"Decision-making enables artificial intelligence to dynamically adjust and acquire knowledge from experiences, distinguishing it from traditional computing intelligence based on predetermined and rigid logic rules. However, the hardness of decision-making within the Turing framework increases exponentially with the number of decisions and decision-agents, thereby limiting the speed and scaling for artificial intelligence to process intensity-heavy tasks. Here, by introducing the quantum advantages of both photons and atoms, we report a photon-atom hybrid decision framework, whose decision-making exploration is accomplished through time-correlated atomic excitation within a quantum memory material. We develop a pseudophotonic blockade effect within memory materials to ensure that decision-making conflicts are hardly generated. With exploring a two-agent <i>N</i>-armed bandit in a concurrent manner, an <i>N</i><sup>2</sup> times acceleration of decision-making exploration compared to nonconcurrent methods is demonstrated. Furthermore, the experimentally characterized performance in preference satisfaction and conflict avoidance shows an advanced capacity for distributed decision-making on a significant scale. Our research advances scalable distributed frameworks to address future reinforcement learning challenges.","PeriodicalId":23,"journal":{"name":"ACS Photonics","volume":"18 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143393769","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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