In some old industrial plants,in order to meet the increasingly strict requirements of pollutant emission limits,it is necessary to install the compact filtration and/or purification devices in a given narrow machine ...In some old industrial plants,in order to meet the increasingly strict requirements of pollutant emission limits,it is necessary to install the compact filtration and/or purification devices in a given narrow machine room.Different types of structural configuration might influence air distribution inside these devices.The unreasonable air distribution might lead each part of filtration or purification media to operating at largely different air flow rates.Based on a computational fluid dynamics(CFD)model,this study explores the influence of different outlet positions and different upper heights on the flow field inside chamber.The porous medium model is employed to simulate the air flow in porous media.The changing structural configurations include three positioning cases of the outlet opening and eight height cases of the upper chamber.The root mean square is defined as the non-uniformity coefficient to evaluate the uniformity of air flow distribution.The results show that the farther distance between inlet and outlet openings will bring more uniform air distribution,and the increasing height of upper chamber totally trends to exhibit more uniform air distribution.展开更多
Metasurfaces have demonstrated unprecedented capabilities in manipulating light with ultrathin and flat architectures.Although great progress has been made in the metasurface designs and function demonstrations,most m...Metasurfaces have demonstrated unprecedented capabilities in manipulating light with ultrathin and flat architectures.Although great progress has been made in the metasurface designs and function demonstrations,most metalenses still only work as a substitution of conventional lenses in optical settings,whose integration advantage is rarely manifested.We propose a highly integrated imaging device with silicon metalenses directly mounted on a complementary metal oxide semiconductor image sensor,whose working distance is in hundreds of micrometers.The imaging performances including resolution,signal-to-noise ratio,and field of view(FOV)are investigated.Moreover,we develop a metalens array with polarization-multiplexed dual-phase design for a wide-field microscopic imaging.This approach remarkably expands the FOV without reducing the resolution,which promises a non-limited space-bandwidth product imaging for wide-field microscopy.As a result,we demonstrate a centimeter-scale prototype for microscopic imaging,showing uniqueness of meta-design for compact integration.展开更多
Braille serves as an efficient means for visually impaired individuals to access textual information and engage in communication.However,the process of reading Braille can often be cumbersome and time-intensive,partic...Braille serves as an efficient means for visually impaired individuals to access textual information and engage in communication.However,the process of reading Braille can often be cumbersome and time-intensive,particularly in bidirectional human-machine interaction.In this work,a compact optical device for contactless detection of Braille is fabricated and characterized.The GaN-on-sapphire chip,which employs monolithic integration,serves as the core for both light emission and photodetection,significantly reducing its overall footprint.The incorporation of the semiellipsoid epoxy lens with optimized dimensions ensures consistent and accurate detection.The sensing device demonstrates high stability and fast response through its line-scanning capabilities on Braille codes.The captured signals are analyzed using a microcontroller,and the Braille recognition results are wirelessly transmitted to a portable mobile device,enabling the conversion into audio and visual formats.This innovative design not only facilitates Braille reading but also holds the potential to advance human-machine interaction.展开更多
The rapid rise of commercial compact fusion devices has triggered fast-growing demand for high-temperature superconducting tapes,creating a major opportunity for the high-temperature superconducting(HTS)tape industry....The rapid rise of commercial compact fusion devices has triggered fast-growing demand for high-temperature superconducting tapes,creating a major opportunity for the high-temperature superconducting(HTS)tape industry.Pulsed laser deposition(PLD)has been extensively applied for fabrication of heteroepitaxial HTS wires or tapes based on REBCO-type superconductor,also referred to as,coated conductors(CCs).A combination of multi-plume,multi-turn deposition technique and use of high-power excimer lasers has enabled and accelerated the industrialization of REBCO coated conductors.Currently,the annual production of top-tier PLD-based,HTS-wire manufacturers exceeds 3,000 km-12 mm,contributing to over half of the total global HTS wire production.PLD-REBCO tapes have demonstrated excellent in-field performance(I_(c)>200 A-4 mm@20K,20T,B//c)and competitive pricing(∼$20/m).PLD technology continues to evolve,demonstrating strong competitive advantages.However,challenges remain in further cost reduction,process stability,and increasing efficiency of raw material utilization.AI-based data mining and tackling emerging fundamental issues are seen as potential solutions to further improve stability and performance.展开更多
Miniaturized spectrometers for Raman spectroscopy have the potential to open up a new chapter in sensing.Raman spectroscopy is essential for material characterization and biomedical diagnostics,however,its weak signal...Miniaturized spectrometers for Raman spectroscopy have the potential to open up a new chapter in sensing.Raman spectroscopy is essential for material characterization and biomedical diagnostics,however,its weak signal and the need for sub-nanometer resolution pose challenges.Conventional spectrometers,with footprints proportional to optical throughput and resolution,are difficult to integrate into compact devices such as wearables.Waveguide-based Fourier Transform Spectrometers(FTS)enable compact spectrometers,and multi-aperture designs can achieve high throughput for applications such as Raman spectroscopy;however,experimental research in this domain remains limited.In this work,we present a multi-aperture SiN waveguide-based FTS overcoming these limitations and enabling Raman spectroscopy of isopropyl alcohol,glucose,Paracetamol,and Ibuprofen with enhanced throughput.Our spectrometer chip,fabricated on a 200mm SiN wafer,with 160 edge-coupled waveguide apertures connected to an array of ultra-compact interferometers and a small footprint of just 1.6mm×3.2 mm,achieves a spectral range of 40 nm and a resolution of 0.5 nm.Experimental results demonstrate that the least absolute shrinkage and selection operator(LASSO)regression significantly enhances Raman spectrum reconstruction.Our work on waveguide-based spectrometry paves the way for integrating accurate and compact Raman sensors into consumer electronics and space exploration instruments.展开更多
Planar cameras with high performance and wide field of view(FOV)are critical in various fields,requiring highly compact and integrated technology.Existing wide FOV metalenses show great potential for ultrathin optical...Planar cameras with high performance and wide field of view(FOV)are critical in various fields,requiring highly compact and integrated technology.Existing wide FOV metalenses show great potential for ultrathin optical components,but there is a set of tricky challenges,such as chromatic aberrations correction,central bright speckle removal,and image quality improvement of wide FOV.We design a neural meta-camera by introducing a knowledge-fused data-driven paradigm equipped with transformer-based network.Such a paradigm enables the network to sequentially assimilate the physical prior and experimental data of the metalens,and thus can effectively mitigate the aforementioned challenges.An ultra-wide FOV metacamera,integrating an off-axis monochromatic aberration-corrected metalens with a neural CMOS image sensor without any relay lenses,is employed to demonstrate the availability.High-quality reconstructed results of color images and real scene images at different distances validate that the proposed metacamera can achieve an ultra-wide FOV(>100 deg)and full-color images with the correction of chromatic aberration,distortion,and central bright speckle,and the contrast increase up to 13.5 times.Notably,coupled with its compact size(<0.13 cm^(3)),portability,and full-color imaging capacity,the neural meta-camera emerges as a compelling alternative for applications,such as micro-navigation,microendoscopes,and various on-chip devices.展开更多
基金National Key Research and Development Program of China(No.2018YFC0705305)。
文摘In some old industrial plants,in order to meet the increasingly strict requirements of pollutant emission limits,it is necessary to install the compact filtration and/or purification devices in a given narrow machine room.Different types of structural configuration might influence air distribution inside these devices.The unreasonable air distribution might lead each part of filtration or purification media to operating at largely different air flow rates.Based on a computational fluid dynamics(CFD)model,this study explores the influence of different outlet positions and different upper heights on the flow field inside chamber.The porous medium model is employed to simulate the air flow in porous media.The changing structural configurations include three positioning cases of the outlet opening and eight height cases of the upper chamber.The root mean square is defined as the non-uniformity coefficient to evaluate the uniformity of air flow distribution.The results show that the farther distance between inlet and outlet openings will bring more uniform air distribution,and the increasing height of upper chamber totally trends to exhibit more uniform air distribution.
基金The authors acknowledge the financial support from the National Key R&D Program of China(Nos.2016YFA0202103 and 2017YFA0303701)the National Natural Science Foundation of China(Nos.91850204 and 11674167)Tao Li thanks the Dengfeng Project B of Nanjing University for the support.The authors declare that they have no conflicts of interest.
文摘Metasurfaces have demonstrated unprecedented capabilities in manipulating light with ultrathin and flat architectures.Although great progress has been made in the metasurface designs and function demonstrations,most metalenses still only work as a substitution of conventional lenses in optical settings,whose integration advantage is rarely manifested.We propose a highly integrated imaging device with silicon metalenses directly mounted on a complementary metal oxide semiconductor image sensor,whose working distance is in hundreds of micrometers.The imaging performances including resolution,signal-to-noise ratio,and field of view(FOV)are investigated.Moreover,we develop a metalens array with polarization-multiplexed dual-phase design for a wide-field microscopic imaging.This approach remarkably expands the FOV without reducing the resolution,which promises a non-limited space-bandwidth product imaging for wide-field microscopy.As a result,we demonstrate a centimeter-scale prototype for microscopic imaging,showing uniqueness of meta-design for compact integration.
基金financial support from the National Natural Science Foundation of China under Grant 12074170in part by the Shenzhen Fundamental Research Program under Grant JCYJ20220530113201003.
文摘Braille serves as an efficient means for visually impaired individuals to access textual information and engage in communication.However,the process of reading Braille can often be cumbersome and time-intensive,particularly in bidirectional human-machine interaction.In this work,a compact optical device for contactless detection of Braille is fabricated and characterized.The GaN-on-sapphire chip,which employs monolithic integration,serves as the core for both light emission and photodetection,significantly reducing its overall footprint.The incorporation of the semiellipsoid epoxy lens with optimized dimensions ensures consistent and accurate detection.The sensing device demonstrates high stability and fast response through its line-scanning capabilities on Braille codes.The captured signals are analyzed using a microcontroller,and the Braille recognition results are wirelessly transmitted to a portable mobile device,enabling the conversion into audio and visual formats.This innovative design not only facilitates Braille reading but also holds the potential to advance human-machine interaction.
基金support from the National Natural Science Foundation of China(Grant No.52277027)the Scientific Research Program of Science and Technology commission of Shanghai Municipality(Grant No.23511101500)+1 种基金financial supported from the China Postdoctoral Science Foundation(Grant No.2024M761969)Amit Goyal acknowledges financial support from Office of Naval Research(ONR),Grant No.N00014-21-1-2534.Hannu Huhtinen and Petriina Paturi acknowledge financial support from the Jenny and Antti Wihuri Foundation.
文摘The rapid rise of commercial compact fusion devices has triggered fast-growing demand for high-temperature superconducting tapes,creating a major opportunity for the high-temperature superconducting(HTS)tape industry.Pulsed laser deposition(PLD)has been extensively applied for fabrication of heteroepitaxial HTS wires or tapes based on REBCO-type superconductor,also referred to as,coated conductors(CCs).A combination of multi-plume,multi-turn deposition technique and use of high-power excimer lasers has enabled and accelerated the industrialization of REBCO coated conductors.Currently,the annual production of top-tier PLD-based,HTS-wire manufacturers exceeds 3,000 km-12 mm,contributing to over half of the total global HTS wire production.PLD-REBCO tapes have demonstrated excellent in-field performance(I_(c)>200 A-4 mm@20K,20T,B//c)and competitive pricing(∼$20/m).PLD technology continues to evolve,demonstrating strong competitive advantages.However,challenges remain in further cost reduction,process stability,and increasing efficiency of raw material utilization.AI-based data mining and tackling emerging fundamental issues are seen as potential solutions to further improve stability and performance.
基金supported by the National Key Research and Development Program of China(No.2024YFF1206300)Guangci Innovative Technology Program(KY2023810)Guangci Talent Program(RC20240018).
文摘Miniaturized spectrometers for Raman spectroscopy have the potential to open up a new chapter in sensing.Raman spectroscopy is essential for material characterization and biomedical diagnostics,however,its weak signal and the need for sub-nanometer resolution pose challenges.Conventional spectrometers,with footprints proportional to optical throughput and resolution,are difficult to integrate into compact devices such as wearables.Waveguide-based Fourier Transform Spectrometers(FTS)enable compact spectrometers,and multi-aperture designs can achieve high throughput for applications such as Raman spectroscopy;however,experimental research in this domain remains limited.In this work,we present a multi-aperture SiN waveguide-based FTS overcoming these limitations and enabling Raman spectroscopy of isopropyl alcohol,glucose,Paracetamol,and Ibuprofen with enhanced throughput.Our spectrometer chip,fabricated on a 200mm SiN wafer,with 160 edge-coupled waveguide apertures connected to an array of ultra-compact interferometers and a small footprint of just 1.6mm×3.2 mm,achieves a spectral range of 40 nm and a resolution of 0.5 nm.Experimental results demonstrate that the least absolute shrinkage and selection operator(LASSO)regression significantly enhances Raman spectrum reconstruction.Our work on waveguide-based spectrometry paves the way for integrating accurate and compact Raman sensors into consumer electronics and space exploration instruments.
基金supported by the National Key R&D Program of China(Grant No.2023YFB2806800)the National Natural Science Foundation of China(Grant Nos.62035016 and U21A20471)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(Grant No.2023B1515040023)the Guangzhou Science and Technology Program(Grant No.202201011671).
文摘Planar cameras with high performance and wide field of view(FOV)are critical in various fields,requiring highly compact and integrated technology.Existing wide FOV metalenses show great potential for ultrathin optical components,but there is a set of tricky challenges,such as chromatic aberrations correction,central bright speckle removal,and image quality improvement of wide FOV.We design a neural meta-camera by introducing a knowledge-fused data-driven paradigm equipped with transformer-based network.Such a paradigm enables the network to sequentially assimilate the physical prior and experimental data of the metalens,and thus can effectively mitigate the aforementioned challenges.An ultra-wide FOV metacamera,integrating an off-axis monochromatic aberration-corrected metalens with a neural CMOS image sensor without any relay lenses,is employed to demonstrate the availability.High-quality reconstructed results of color images and real scene images at different distances validate that the proposed metacamera can achieve an ultra-wide FOV(>100 deg)and full-color images with the correction of chromatic aberration,distortion,and central bright speckle,and the contrast increase up to 13.5 times.Notably,coupled with its compact size(<0.13 cm^(3)),portability,and full-color imaging capacity,the neural meta-camera emerges as a compelling alternative for applications,such as micro-navigation,microendoscopes,and various on-chip devices.
