The laser-assisted manufacturing technology has significant advantages in meeting various demands such as complex structures,functional integration,customized devices,and cost-effectiveness,which makes it a highly att...The laser-assisted manufacturing technology has significant advantages in meeting various demands such as complex structures,functional integration,customized devices,and cost-effectiveness,which makes it a highly attractive option for fabricating sensors.In this review,the latest advancements and strategies in intelligent sensor development through laser processing were surveyed and outlined following the interaction of laser and materials.Laser-assisted manufacturing technologies have been extensively applied in materials science and device processing.Firstly,laser technology can be utilized in a wide range of materials,encompassing carbon-based materials,metals,and metallic oxides.In the field of device scale processing,laser manufacturing is widely used in micro/nano structures,planar device construction,and stereoscopic electronic devices such as cutting,engraving,and lithography.Additionally,laser technology provides robust support for sensor applications,covering fields such as pressure sensing,temperature sensing,gas sensing,and biosensors.Furthermore,laser considerably serves in real application areas such as multifunctional sensing systems,actuators,and robots.The widespread application of laser manufacturing technology in sensor platform fabrication offers effective solutions for realizing the miniaturization,multifunctionality,and integration of sensors.展开更多
This review examines the state-of-the-art in spatial manipulation of ultrafast laser processing using dynamic light modulators,with a particular focus on liquid crystal-based systems.We discuss phase modulation strate...This review examines the state-of-the-art in spatial manipulation of ultrafast laser processing using dynamic light modulators,with a particular focus on liquid crystal-based systems.We discuss phase modulation strategies and highlight the current limitations and challenges in surface and bulk processing.Specifically,we emphasize the delicate balance between high-fidelity beam shaping and energy efficiency,both critical for surface and bulk processing applications.Given the inherent physical limitations of spatial light modulators such as spatial resolution,fill factor,and phase modulation range.We explore techniques developed to bridge the gap between desired intensity distributions and actual experimental beam profiles.We present various laser light modulation technologies and the main algorithmic strategies for obtaining modulation patterns.The paper includes application examples across a wide range of fields,from surgery to surface structuring,cutting,bulk photo-inscription of optical functions,and additive manufacturing,highlighting the significant enhancements in processing speed and precision due to spatial beam shaping.The diverse applications and the technological limitations underscore the need for adapted modulation pattern calculation methods.We discuss several advancements addressing these challenges,involving both experimental and algorithmic developments,including the recent incorporation of artificial intelligence.Additionally,we cover recent progress in phase and pulse front control based on spatial modulators,which introduces an extra control parameter for light excitation with high potential for achieving more controlled processing outcomes.展开更多
The concepts of “confining structure” and structure light are illuminated in this paper.A laser theodolite with three freedoms of rotation,which is aimed at “confining structure”,is developed.Various scanning mode...The concepts of “confining structure” and structure light are illuminated in this paper.A laser theodolite with three freedoms of rotation,which is aimed at “confining structure”,is developed.Various scanning modes and their mathematical models based on laser theodolite with three freedoms of rotation are discussed.According to the features of a huge object,,the structure light engineering surveying based on laser theodolite with three freedoms of rotation is determined as the main method in an actual application.The observation of four sound concrete posts and forced centering plates.Subsequently,it is transformed into the huge object coordinate system.The scanning mode with plumb plane is selected as the main mode in the whole work.And other assistant methods,such as close range photogrammetry and the method of using reflection sheet,are applied to the work of “scanning dead angle”.At last,a surveying accuracy estimation of this method is done and a surveying accuracy test is finished.It can be concluded that the structure light engineering surveying based on laser theodolite with three freedoms of rotation is considered to be an effective and applied method,and has many superiority to some other surveying methods in the work of surveying “confining structure”.展开更多
This paper presents the principle and mathematic model for the 3D depth map method based on space encoding images performed by modulating scanning structuredlight according to time sequences,and the synchro control ...This paper presents the principle and mathematic model for the 3D depth map method based on space encoding images performed by modulating scanning structuredlight according to time sequences,and the synchro control among the camera,laser diode modulation and scanning polyhedron.展开更多
We have investigated the properties of cellulose diacetate in solution by using laser light scattering. The cellulose diacetate molecules can form micelles and micellar clusters in acetone besides the individual chain...We have investigated the properties of cellulose diacetate in solution by using laser light scattering. The cellulose diacetate molecules can form micelles and micellar clusters in acetone besides the individual chains. As the concentration increases, the average hydrodynamic radius （Rh） linearly increases, whereas the ratio of gyration radius to hydrodynamic radins 〈Rg〉/〈Rh〉 linearly decreases. It indicates that the micelles associate and form micellar clusters due to the intermolecular interactions.展开更多
The current work aims at evaluating a proposed method based on a computational tool developed using Object-Oriented Programming to identify the status of micro-structured surfaces. In this case, these are micro-struct...The current work aims at evaluating a proposed method based on a computational tool developed using Object-Oriented Programming to identify the status of micro-structured surfaces. In this case, these are micro-structured coatings with riblet microstructure developed by Fraunhofer Institute–IFAM, by building a graphical reproduction of the analyzed surface and calculating an expected laser reflection intensity acquired by a laser sensor device, the proposed method is assessed by using the simplest case: a flat surface, and an optimal case: an intact riblet surface. The results corroborate the calculations to be applied to further steps from more complex cases of degradation and to diverse riblets geometries. Based on Huygens-Fresnel and Fraunhofer diffraction theories, the calculations developed and demonstrated in this paper improved the nondestructive tests to support the status identification of the micro structured coatings, e.g. riblet structures based on shark skin used in shipping and aerospace industries. This work is assured required quality of the riblet coating identifying the number of structures and expected geometry using implemented calculations to foresee the laser reflection intensity acquired by a laser sensor device with 3 detectors, for instance, a riblet structure could be graphically reproduced, analyzed and completely identified based on the application of the theoretical optics applied on this work.展开更多
In this paper,a series of new techniques are used to optimize typical laser scanning sensor.The integrated prototype is compared with traditional approach to demonstrate the much improved performance.In the research a...In this paper,a series of new techniques are used to optimize typical laser scanning sensor.The integrated prototype is compared with traditional approach to demonstrate the much improved performance.In the research and development,camera calibration is achieved by extracting characteristic points of the laser plane,so that the calibra- tion efficiency is improved significantly.With feedback control of its intensity,the laser is automatically adjusted for different material.A modified algorithm is presented to improve the accuracy of laser stripe extraction.The fusion of data extracted from left and right camera is completed with re-sampling technique.The scanner is integrated with a robot arm and some other machinery for on-line measurement and inspection,which provides a flexible measurement tool for reverse engineering.展开更多
In this study, a three-dimensional (3D) in-situ laser machining system integrating laser measurement and machining was built using a 3D galvanometer scanner equipped with a side-axis industrial camera. A line structur...In this study, a three-dimensional (3D) in-situ laser machining system integrating laser measurement and machining was built using a 3D galvanometer scanner equipped with a side-axis industrial camera. A line structured light measurement model based on a galvanometer scanner was proposed to obtain the 3D information of the workpiece. A height calibration method was proposed to further ensure measurement accuracy, so as to achieve accurate laser focusing. In-situ machining software was developed to realize time-saving and labor-saving 3D laser processing. The feasibility and practicability of this in-situ laser machining system were verified using specific cases. In comparison with the conventional line structured light measurement method, the proposed methods do not require light plane calibration, and do not need additional motion axes for 3D reconstruction;thus they provide technical and cost advantages. The insitu laser machining system realizes a simple operation process by integrating measurement and machining,which greatly reduces labor and time costs.展开更多
In this paper, a flexible high-precision calibration method suitable for industrial field was proposed. The complexity of the coordinate transformation was simplified by choosing the camera coordinate system as the un...In this paper, a flexible high-precision calibration method suitable for industrial field was proposed. The complexity of the coordinate transformation was simplified by choosing the camera coordinate system as the unified reference coordinate system. A flexible planar calibration pattern was introduced to the calibration process, which can be arbitrarily placed and from which the known feature points can be extracted to construct other unknown feature points. With the known intrinsic parameters, the laser projector plane equation was fitted by the multi-noncollinear points, which were acquired through the principle of triangulation and the projective invariance of cross ratio. With this method, the strict alignment and multiple times of coordinate transformation can be avoided. Experimental results showed that the arithmetic mean of the root mean square(RMS) error of distance was 0.000 7 mm.展开更多
Intraocular lens (IOLs) implants are synthetic lenses used to replace the natural lens of the eye and obtain optical reha- bilitation. The materials and methods of IOLs fabrication have been correlated with postoperat...Intraocular lens (IOLs) implants are synthetic lenses used to replace the natural lens of the eye and obtain optical reha- bilitation. The materials and methods of IOLs fabrication have been correlated with postoperative complications such as diffractive aberrations, capsular opacification or discoloration. Thus, several new materials and patterns are studied for the formation and etching of intraocular lenses (IOLs). In our work, we studied the use of UV laser as an alternative method to conventional surface shaping techniques for IOLs etching. Ablation experiments were conducted on hydrophobic acrylic IOLs by a commercial excimer laser system used in photorefractive surgery. The morphology of the irradiated area was observed by scanning electron microscopy (SEM) and a mathematical algorithm was used for SEM image processing. The effect of IOLs exposure to UV light before excimer laser irradiation was also examined, since natural ageing and cross-linking of IOLs material were reported. Conical structures were revealed after UV laser ablation and their population was increased with the number of laser pulses. Period distribution of cones was measured with the combination of image processing and a scanning algorithm which was developed for this reason. According to the graphs, the mean period and the distribution of the cones was depending of the number of irradiation pulses and the exposure to UV lamp before laser irradiation. Although a photochemical and a theoretically smooth-surface ablation mechanism is considered for the UV excimer laser interaction with polymers, surface conical-like abnormalities and thermal degradation of the lenses materials was observed.展开更多
Flat, straight sheets of paper, standing vertically on edge cannot support any load placed upon their top edge, but once formed into fractal tube conic sections, they have been measured to support up to 97.52 (± ...Flat, straight sheets of paper, standing vertically on edge cannot support any load placed upon their top edge, but once formed into fractal tube conic sections, they have been measured to support up to 97.52 (± 2.27) kilograms (215 (± 5) pounds) of weight with strength-per-weight ratio up to 10,336 (± 240). So, strength has been discovered to be an emergent characteristic arising solely from addition of intelligent order. It is proposed to impose such intelligent order upon, preferably, at least 6 laser beams by focusing each of them to form cones of light, arranging the cones to form a wall of a larger fractal cone, and converging all of them to a common focal point inside a vacuum chamber to give them sufficient strength near this focal point to attract, hold, and move neutral antimatter, preferably anti-lithium. This opens the new field of structural engineering of light and re-defines the concept of strength. Means of cancelling out radiation pressure by reflection of laser beams back to the common focal point are proposed to enable laser confinement of particles having low polarizability, such as anti-hydrogen. Counter-circulation of light by reflection at grazing incidence is proposed as a means of returning escaping antimatter back to the common focal point containment area. Means are proposed to inject a stream of matter into the contained antimatter to create a matter-antimatter reactor and propulsion engine. Since anti-lithium is not available, yet, means are proposed to test these structures by confining ordinary lithium, instead, and by hitting it with anti-protons and/or positrons. Means are proposed to modulate the matter-antimatter reaction with information to create modulated gravitational waves for communication. The proposed structures would enable efficient, stable, safe confinement of antimatter, which would allow better study of antimatter, and make possible renewable, clean, safe, matter-antimatter reactor generators and propulsion engines, antimatter-assisted fusion reactors, and modulated gravitational wave generators.展开更多
Vortex fiber lasers that directly deliver low-cost and high-performance vortex beams could provide straightfor-ward and compact solutions for structured laser sources and have found applications in various fields.Suff...Vortex fiber lasers that directly deliver low-cost and high-performance vortex beams could provide straightfor-ward and compact solutions for structured laser sources and have found applications in various fields.Suffering from either simple and fixed functionality,or large insertion loss together with bulky configurations of phase modulation components such as q-plates and spatial light modulators,the output flexibility and tunability of conventional vortex fiber lasers are limited.Recently,polarization-multiplexing metasurfaces(PMMs)have shown powerful potential for manipulating light in different dimensions.Here we propose and experimentally demonstrate topological charge switchable vortex fiber lasers assisted by on-demand customized PMMs.Importantly,by adjusting the setting of the wave plates within the cavity,the topological charge of the output vortex beams can be effectively switched and even decoupled at will.The design principle and experimental verification offer new perspectives for vortex fiber laser configurations,offering promising applications from large-capacity optical communication and particle manipulation to super-resolution microscopy and quantum information processing.展开更多
Flexible strain sensors with high sensitivity and stability at high temperatures are significantly desirable for their accurate and long-term signal detection in wearable devices,environment monitoring,and aerospace e...Flexible strain sensors with high sensitivity and stability at high temperatures are significantly desirable for their accurate and long-term signal detection in wearable devices,environment monitoring,and aerospace electronics.Despite the considerable efforts in materials development and structural design,it remains a challenge to develop highly sensitive,flexible strain sensors operating at high temperatures due to the trade-off between sensitivity and stability for the representative sensing materials.Herein,we develop a high-temperature flexible sensor using Mo_(x)W_(1-x)S_(2) alloy films.A pulsed laser is introduced to directly synthesize Mo_(x)W_(1-x)S_(2) patterns with controllable compositions and physical parameters,enabling the realization of flexible sensors without photolithography or transfer procedures.The resultant flexible sensors exhibit a high gauge factor of 97.4,a low strain detection of 4.9με,and strong tolerance to a temperature of 500℃.Owing to its superior performance,we develop a wireless acoustic recognition system to distinguish tiny strain signals of tuning forks with a vibration frequency up to 128 Hz under extreme temperature conditions.The laser method for the direct fabrication of Mo_(x)W_(1-x)S_(2) alloy-based flexible sensors holds great potential in the precise detection of strain signals from complex structures at high temperatures.展开更多
This paper presents a compact and high-performance piezoelectric micro-electro-mechanical system(MEMS)fast steering mirror(FSM)designed for use in laser inter-satellite links(ISLs).The FSM features a large optical ape...This paper presents a compact and high-performance piezoelectric micro-electro-mechanical system(MEMS)fast steering mirror(FSM)designed for use in laser inter-satellite links(ISLs).The FSM features a large optical aperture of 10 mm and is batch fabricated using an 8-inch wafer-level eutectic bonding process,packaged into a volume of 26×22×3 mm3.Notably,the piezoresistive(PZR)sensor is integrated on the spring of the FSM to facilitate precise beam control.Furthermore,an intermediate directional defect structure is novelly designed to create a Stress Concentration Region(SCR),effectively improving PZR sensitivity from 3.3 mV/(V∙mrad)to 5.4 mV/(V∙mrad).In this article,various performance metrics of the FSM are tested,including the mechanical characteristics,PZR sensor properties,and mirror optical quality,which all meet the requirements for laser ISLs.Results indicate that the FSM achieves a high resonant frequency(>1 kHz)and a low nonlinearity of 0.05%@±2.1 mrad.A remarkable minimum angular resolution of 0.3μrad and a repeated positioning accuracy of 1.11μrad ensure exceptional pointing precision.The open-loop control is driven by the double-step algorithm,resulting in a step response time of 0.41 ms and achieving a control bandwidth over 2 kHz.Additionally,the integrated angular sensor demonstrates a nonlinearity of 0.09%@±1.05 mrad,a sensitivity of 5.1 mV/(V∙mrad),and a minimum angular resolution of 0.3μrad.Under quasi-static driven conditions(500 Hz@±2 mrad),the maximum dynamic deformation of the mirror surface is merely 2 nm.展开更多
The accuracy of center height detection for corrugated beam guardrails is significantly affected by robot posture in the mobile highway guardrail detection systems based on structured light vision.To address the probl...The accuracy of center height detection for corrugated beam guardrails is significantly affected by robot posture in the mobile highway guardrail detection systems based on structured light vision.To address the problem,this paper proposes an integrated calibration method for structured light vision sensors.In the proposed system,the sensor is mounted on a crawler-type mobile robot,which scans and measures the center height of guardrails while in motion.However,due to external disturbances such as uneven road surfaces and vehicle vibrations,the posture of the robot may deviate,causing displacement of the sensor platform and resulting in spatial 3D measurement errors.To overcome this issue,the system integrates inertial measurement unit(IMU)data into the sensor calibration process,enabling realtime correction of posture deviations through sensor fusion.This approach achieves a unified calibration of the structured light vision system,effectively compensates for posture-induced errors,and enhances detection accuracy.A prototype was developed and tested in both laboratory and real highway environments.Experimental results demonstrate that the proposed method enables accurate center height detection of guardrails under complex road conditions,significantly reduces posture-related measurement errors,and greatly improves the efficiency and reliability of traditional detection methods.展开更多
Since the invention of lasers,spatial-light-modulated laser processing has become a powerful tool for various applications.It enables multidimensional and dynamic modulation of the laser beam,which significantly impro...Since the invention of lasers,spatial-light-modulated laser processing has become a powerful tool for various applications.It enables multidimensional and dynamic modulation of the laser beam,which significantly improves the processing efficiency,accuracy,and flexibility,and presents wider prospects over traditional mechanical technologies for machining three-dimensional,hard,brittle,or transparent materials.In this review,we introduce:(1)The role of spatial light modulation technology in the development of femtosecond laser manufacturing;(2)the structured light generated by spatial light modulation and its generation methods;and(3)representative applications of spatial-light-modulated femtosecond laser manufacturing,including aberration correction,parallel processing,focal field engineering,and polarization control.Finally,we summarize the present challenges in the field and possible future research.展开更多
Molybdenum disulfide(MoS_(2))-based nanostructures are highly desirable for applications such as chemical and biological sensing,photo/electrochemical catalysis,and energy storage due to their unique physical and chem...Molybdenum disulfide(MoS_(2))-based nanostructures are highly desirable for applications such as chemical and biological sensing,photo/electrochemical catalysis,and energy storage due to their unique physical and chemical properties.In this work,MoS_(2)core-shell nanoparticles were first prepared through the liquid-phase processing of bulk MoS2by a femtosecond laser.The core of prepared nanoparticles was incompletely and weakly crystalline MoS_(2);the shell of prepared nanoparticles was highly crystalline MoS_(2),which wrapped around the core layer by layer.The femtosecond laser simultaneously achieved liquid-phase ablation and light exfoliation.The formation mechanism of the core-shell nanoparticles is to prepare the nanonuclei first by laser liquid-phase ablation and then the nanosheets by light exfoliation;the nanosheets will wrap the nanonuclei layer by layer through van der Waals forces to form core-shell nanoparticles.The MoS_(2)core-shell nanoparticles,because of Mo-S bond breakage and recombination,have high chemical activity for chemical catalysis.Afterward,the nanoparticles were used as a reducing agent to directly prepare three-dimensional(3D)Au-MoS_(2)micro/nanostructures,which were applied as surface-enhanced Raman spectroscopy(SERS)substrates to explore chemical sensing activity.The ultrahigh enhancement factor(1.06×10^(11)),ultralow detection limit(10-13M),and good SERS adaptability demonstrate highly sensitive SERS activity,great ability of ultralow concentration detection,and ability to detect diverse analytes,respectively.This work reveals the tremendous potential of 3D Au-MoS_(2)composite structures as excellent SERS substrates for chemical and biological sensing.展开更多
This paper presents an investigation of the secondary saturation characteristics of a HfTe_(2)saturable absorber.Pulse energies of 5.85 and 7.4 mJ were demonstrated with a high-order Hermite-Gaussian(HG)laser and a vo...This paper presents an investigation of the secondary saturation characteristics of a HfTe_(2)saturable absorber.Pulse energies of 5.85 and 7.4 mJ were demonstrated with a high-order Hermite-Gaussian(HG)laser and a vortex laser,respectively,using alexandrite as the gain medium.To the best of our knowledge,these are the highest pulse energies directly generated with HG and vortex lasers.To broaden the applications of high-energy pulsed HG and vortex lasers,wavelength tuning in the region of 40 nm was achieved using an etalon.pulse energy of 5.85 mJ and a vortex laser with a single pulse energy of 7.4 mJ were obtained in alexandrite.The repetition rates of these lasers were 262 and 196 Hz,respectively.To expand the applications of high-energy structured lasers,wavelength tuning within the range of 747-787 nm was successfully accomplished using an etalon.展开更多
High-aspect-ratio structures with heights or depths significantly exceeding their lateral dimensions hold broad application potential across various fields.The production of these structures is challenging,requiring m...High-aspect-ratio structures with heights or depths significantly exceeding their lateral dimensions hold broad application potential across various fields.The production of these structures is challenging,requiring meticulous control over materials,scale,and precision.We introduce an economical and efficient approach for fabricating high-aspect-ratio nanostructures using a two-photon polymerization process.This approach achieves feature sizes of around 37 nm with an aspect ratio of 10:1 using commercial photoresists.Offering advantages over traditional techniques,our approach simplifies operation and enhances design flexibility,facilitating the creation of smaller,more complex,and high-aspect-ratio structures.The capabilities of this approach are demonstrated by producing arrays of three-dimensional microstructures that exhibit sub-micron scales,extensive periodicity,and pronounced aspect ratios.These developments open new possibilities for applications in biomedical,precision engineering,and optical microdevice manufacturing.展开更多
Processing of materials by ultrashort laser pulses has evolved significantly over the last decade and is starting to reveal its scientific,technological and industrial potential.In ultrafast laser manufacturing,optica...Processing of materials by ultrashort laser pulses has evolved significantly over the last decade and is starting to reveal its scientific,technological and industrial potential.In ultrafast laser manufacturing,optical energy of tightly focused femtosecond or picosecond laser pulses can be delivered to precisely defined positions in the bulk of materials via two-/multi-photon excitation on a timescale much faster than thermal energy exchange between photoexcited electrons and lattice ions.Control of photoionization and thermal processes with the highest precision,inducing local photomodification in sub-100-nm-sized regions has been achieved.State-of-the-art ultrashort laser processing techniques exploit high 0.1–1μm spatial resolution and almost unrestricted three-dimensional structuring capability.Adjustable pulse duration,spatiotemporal chirp,phase front tilt and polarization allow control of photomodification via uniquely wide parameter space.Mature opto-electrical/mechanical technologies have enabled laser processing speeds approaching meters-per-second,leading to a fast lab-to-fab transfer.The key aspects and latest achievements are reviewed with an emphasis on the fundamental relation between spatial resolution and total fabrication throughput.Emerging biomedical applications implementing micrometer feature precision over centimeter-scale scaffolds and photonic wire bonding in telecommunications are highlighted.展开更多
基金supported by National Key Research and Development Program of China(2023YFB3210400)the National Natural Science Foundation of China(52472097 and 52102171)+2 种基金Natural Science Foundation of Shandong Province(ZR2021JQ15,ZR2023LLZ008 and ZR2022YQ42)Taishan Scholar Project of Shandong Province(tstp20240515)Innovative Team Project of Jinan(2021GXRC019).
文摘The laser-assisted manufacturing technology has significant advantages in meeting various demands such as complex structures,functional integration,customized devices,and cost-effectiveness,which makes it a highly attractive option for fabricating sensors.In this review,the latest advancements and strategies in intelligent sensor development through laser processing were surveyed and outlined following the interaction of laser and materials.Laser-assisted manufacturing technologies have been extensively applied in materials science and device processing.Firstly,laser technology can be utilized in a wide range of materials,encompassing carbon-based materials,metals,and metallic oxides.In the field of device scale processing,laser manufacturing is widely used in micro/nano structures,planar device construction,and stereoscopic electronic devices such as cutting,engraving,and lithography.Additionally,laser technology provides robust support for sensor applications,covering fields such as pressure sensing,temperature sensing,gas sensing,and biosensors.Furthermore,laser considerably serves in real application areas such as multifunctional sensing systems,actuators,and robots.The widespread application of laser manufacturing technology in sensor platform fabrication offers effective solutions for realizing the miniaturization,multifunctionality,and integration of sensors.
基金supported by the French ANRT agence nationale de la recherche technologique under the CIFRE conventions industrielles de formation par la recherche framework.
文摘This review examines the state-of-the-art in spatial manipulation of ultrafast laser processing using dynamic light modulators,with a particular focus on liquid crystal-based systems.We discuss phase modulation strategies and highlight the current limitations and challenges in surface and bulk processing.Specifically,we emphasize the delicate balance between high-fidelity beam shaping and energy efficiency,both critical for surface and bulk processing applications.Given the inherent physical limitations of spatial light modulators such as spatial resolution,fill factor,and phase modulation range.We explore techniques developed to bridge the gap between desired intensity distributions and actual experimental beam profiles.We present various laser light modulation technologies and the main algorithmic strategies for obtaining modulation patterns.The paper includes application examples across a wide range of fields,from surgery to surface structuring,cutting,bulk photo-inscription of optical functions,and additive manufacturing,highlighting the significant enhancements in processing speed and precision due to spatial beam shaping.The diverse applications and the technological limitations underscore the need for adapted modulation pattern calculation methods.We discuss several advancements addressing these challenges,involving both experimental and algorithmic developments,including the recent incorporation of artificial intelligence.Additionally,we cover recent progress in phase and pulse front control based on spatial modulators,which introduces an extra control parameter for light excitation with high potential for achieving more controlled processing outcomes.
文摘The concepts of “confining structure” and structure light are illuminated in this paper.A laser theodolite with three freedoms of rotation,which is aimed at “confining structure”,is developed.Various scanning modes and their mathematical models based on laser theodolite with three freedoms of rotation are discussed.According to the features of a huge object,,the structure light engineering surveying based on laser theodolite with three freedoms of rotation is determined as the main method in an actual application.The observation of four sound concrete posts and forced centering plates.Subsequently,it is transformed into the huge object coordinate system.The scanning mode with plumb plane is selected as the main mode in the whole work.And other assistant methods,such as close range photogrammetry and the method of using reflection sheet,are applied to the work of “scanning dead angle”.At last,a surveying accuracy estimation of this method is done and a surveying accuracy test is finished.It can be concluded that the structure light engineering surveying based on laser theodolite with three freedoms of rotation is considered to be an effective and applied method,and has many superiority to some other surveying methods in the work of surveying “confining structure”.
文摘This paper presents the principle and mathematic model for the 3D depth map method based on space encoding images performed by modulating scanning structuredlight according to time sequences,and the synchro control among the camera,laser diode modulation and scanning polyhedron.
基金ACKNOWLEDGMENTS This work was supported by China Tobacco Guangdong Industrial Co., Ltd., National Natural Science Foundation of China （No21234003 and No.51303059）, and the Fundamental Research Funds for Central Universities.
文摘We have investigated the properties of cellulose diacetate in solution by using laser light scattering. The cellulose diacetate molecules can form micelles and micellar clusters in acetone besides the individual chains. As the concentration increases, the average hydrodynamic radius （Rh） linearly increases, whereas the ratio of gyration radius to hydrodynamic radins 〈Rg〉/〈Rh〉 linearly decreases. It indicates that the micelles associate and form micellar clusters due to the intermolecular interactions.
文摘The current work aims at evaluating a proposed method based on a computational tool developed using Object-Oriented Programming to identify the status of micro-structured surfaces. In this case, these are micro-structured coatings with riblet microstructure developed by Fraunhofer Institute–IFAM, by building a graphical reproduction of the analyzed surface and calculating an expected laser reflection intensity acquired by a laser sensor device, the proposed method is assessed by using the simplest case: a flat surface, and an optimal case: an intact riblet surface. The results corroborate the calculations to be applied to further steps from more complex cases of degradation and to diverse riblets geometries. Based on Huygens-Fresnel and Fraunhofer diffraction theories, the calculations developed and demonstrated in this paper improved the nondestructive tests to support the status identification of the micro structured coatings, e.g. riblet structures based on shark skin used in shipping and aerospace industries. This work is assured required quality of the riblet coating identifying the number of structures and expected geometry using implemented calculations to foresee the laser reflection intensity acquired by a laser sensor device with 3 detectors, for instance, a riblet structure could be graphically reproduced, analyzed and completely identified based on the application of the theoretical optics applied on this work.
文摘In this paper,a series of new techniques are used to optimize typical laser scanning sensor.The integrated prototype is compared with traditional approach to demonstrate the much improved performance.In the research and development,camera calibration is achieved by extracting characteristic points of the laser plane,so that the calibra- tion efficiency is improved significantly.With feedback control of its intensity,the laser is automatically adjusted for different material.A modified algorithm is presented to improve the accuracy of laser stripe extraction.The fusion of data extracted from left and right camera is completed with re-sampling technique.The scanner is integrated with a robot arm and some other machinery for on-line measurement and inspection,which provides a flexible measurement tool for reverse engineering.
文摘In this study, a three-dimensional (3D) in-situ laser machining system integrating laser measurement and machining was built using a 3D galvanometer scanner equipped with a side-axis industrial camera. A line structured light measurement model based on a galvanometer scanner was proposed to obtain the 3D information of the workpiece. A height calibration method was proposed to further ensure measurement accuracy, so as to achieve accurate laser focusing. In-situ machining software was developed to realize time-saving and labor-saving 3D laser processing. The feasibility and practicability of this in-situ laser machining system were verified using specific cases. In comparison with the conventional line structured light measurement method, the proposed methods do not require light plane calibration, and do not need additional motion axes for 3D reconstruction;thus they provide technical and cost advantages. The insitu laser machining system realizes a simple operation process by integrating measurement and machining,which greatly reduces labor and time costs.
基金Supported by the National Natural Science Foundation of China(No.51105273)
文摘In this paper, a flexible high-precision calibration method suitable for industrial field was proposed. The complexity of the coordinate transformation was simplified by choosing the camera coordinate system as the unified reference coordinate system. A flexible planar calibration pattern was introduced to the calibration process, which can be arbitrarily placed and from which the known feature points can be extracted to construct other unknown feature points. With the known intrinsic parameters, the laser projector plane equation was fitted by the multi-noncollinear points, which were acquired through the principle of triangulation and the projective invariance of cross ratio. With this method, the strict alignment and multiple times of coordinate transformation can be avoided. Experimental results showed that the arithmetic mean of the root mean square(RMS) error of distance was 0.000 7 mm.
文摘Intraocular lens (IOLs) implants are synthetic lenses used to replace the natural lens of the eye and obtain optical reha- bilitation. The materials and methods of IOLs fabrication have been correlated with postoperative complications such as diffractive aberrations, capsular opacification or discoloration. Thus, several new materials and patterns are studied for the formation and etching of intraocular lenses (IOLs). In our work, we studied the use of UV laser as an alternative method to conventional surface shaping techniques for IOLs etching. Ablation experiments were conducted on hydrophobic acrylic IOLs by a commercial excimer laser system used in photorefractive surgery. The morphology of the irradiated area was observed by scanning electron microscopy (SEM) and a mathematical algorithm was used for SEM image processing. The effect of IOLs exposure to UV light before excimer laser irradiation was also examined, since natural ageing and cross-linking of IOLs material were reported. Conical structures were revealed after UV laser ablation and their population was increased with the number of laser pulses. Period distribution of cones was measured with the combination of image processing and a scanning algorithm which was developed for this reason. According to the graphs, the mean period and the distribution of the cones was depending of the number of irradiation pulses and the exposure to UV lamp before laser irradiation. Although a photochemical and a theoretically smooth-surface ablation mechanism is considered for the UV excimer laser interaction with polymers, surface conical-like abnormalities and thermal degradation of the lenses materials was observed.
文摘Flat, straight sheets of paper, standing vertically on edge cannot support any load placed upon their top edge, but once formed into fractal tube conic sections, they have been measured to support up to 97.52 (± 2.27) kilograms (215 (± 5) pounds) of weight with strength-per-weight ratio up to 10,336 (± 240). So, strength has been discovered to be an emergent characteristic arising solely from addition of intelligent order. It is proposed to impose such intelligent order upon, preferably, at least 6 laser beams by focusing each of them to form cones of light, arranging the cones to form a wall of a larger fractal cone, and converging all of them to a common focal point inside a vacuum chamber to give them sufficient strength near this focal point to attract, hold, and move neutral antimatter, preferably anti-lithium. This opens the new field of structural engineering of light and re-defines the concept of strength. Means of cancelling out radiation pressure by reflection of laser beams back to the common focal point are proposed to enable laser confinement of particles having low polarizability, such as anti-hydrogen. Counter-circulation of light by reflection at grazing incidence is proposed as a means of returning escaping antimatter back to the common focal point containment area. Means are proposed to inject a stream of matter into the contained antimatter to create a matter-antimatter reactor and propulsion engine. Since anti-lithium is not available, yet, means are proposed to test these structures by confining ordinary lithium, instead, and by hitting it with anti-protons and/or positrons. Means are proposed to modulate the matter-antimatter reaction with information to create modulated gravitational waves for communication. The proposed structures would enable efficient, stable, safe confinement of antimatter, which would allow better study of antimatter, and make possible renewable, clean, safe, matter-antimatter reactor generators and propulsion engines, antimatter-assisted fusion reactors, and modulated gravitational wave generators.
基金National Natural Science Foundation of China(61905018)Fundamental Research Funds for the Central Universities(ZDYY202102)State Key Laboratory of InformationPhotonics and Optical Communications(IPOC2021ZR02).
文摘Vortex fiber lasers that directly deliver low-cost and high-performance vortex beams could provide straightfor-ward and compact solutions for structured laser sources and have found applications in various fields.Suffering from either simple and fixed functionality,or large insertion loss together with bulky configurations of phase modulation components such as q-plates and spatial light modulators,the output flexibility and tunability of conventional vortex fiber lasers are limited.Recently,polarization-multiplexing metasurfaces(PMMs)have shown powerful potential for manipulating light in different dimensions.Here we propose and experimentally demonstrate topological charge switchable vortex fiber lasers assisted by on-demand customized PMMs.Importantly,by adjusting the setting of the wave plates within the cavity,the topological charge of the output vortex beams can be effectively switched and even decoupled at will.The design principle and experimental verification offer new perspectives for vortex fiber laser configurations,offering promising applications from large-capacity optical communication and particle manipulation to super-resolution microscopy and quantum information processing.
基金supported by the National Natural Science Foundation of China(No.62288102,62371397,62304182,and 62471396)the Fundamental Research Funds for the Central Universities,the Young Talent Fund of Xi’an Association for Science and Technology(No.959202413089)Engineering Research Center of Flexible Electronics,Universities of Shaanxi Province,and Open Test Funding Project from Analytical&Testing Center of Northwestern Polytechnical University(No.2023T008).
文摘Flexible strain sensors with high sensitivity and stability at high temperatures are significantly desirable for their accurate and long-term signal detection in wearable devices,environment monitoring,and aerospace electronics.Despite the considerable efforts in materials development and structural design,it remains a challenge to develop highly sensitive,flexible strain sensors operating at high temperatures due to the trade-off between sensitivity and stability for the representative sensing materials.Herein,we develop a high-temperature flexible sensor using Mo_(x)W_(1-x)S_(2) alloy films.A pulsed laser is introduced to directly synthesize Mo_(x)W_(1-x)S_(2) patterns with controllable compositions and physical parameters,enabling the realization of flexible sensors without photolithography or transfer procedures.The resultant flexible sensors exhibit a high gauge factor of 97.4,a low strain detection of 4.9με,and strong tolerance to a temperature of 500℃.Owing to its superior performance,we develop a wireless acoustic recognition system to distinguish tiny strain signals of tuning forks with a vibration frequency up to 128 Hz under extreme temperature conditions.The laser method for the direct fabrication of Mo_(x)W_(1-x)S_(2) alloy-based flexible sensors holds great potential in the precise detection of strain signals from complex structures at high temperatures.
基金the support from the National Key Research and Development Program of China(no.2023YFB3209900).
文摘This paper presents a compact and high-performance piezoelectric micro-electro-mechanical system(MEMS)fast steering mirror(FSM)designed for use in laser inter-satellite links(ISLs).The FSM features a large optical aperture of 10 mm and is batch fabricated using an 8-inch wafer-level eutectic bonding process,packaged into a volume of 26×22×3 mm3.Notably,the piezoresistive(PZR)sensor is integrated on the spring of the FSM to facilitate precise beam control.Furthermore,an intermediate directional defect structure is novelly designed to create a Stress Concentration Region(SCR),effectively improving PZR sensitivity from 3.3 mV/(V∙mrad)to 5.4 mV/(V∙mrad).In this article,various performance metrics of the FSM are tested,including the mechanical characteristics,PZR sensor properties,and mirror optical quality,which all meet the requirements for laser ISLs.Results indicate that the FSM achieves a high resonant frequency(>1 kHz)and a low nonlinearity of 0.05%@±2.1 mrad.A remarkable minimum angular resolution of 0.3μrad and a repeated positioning accuracy of 1.11μrad ensure exceptional pointing precision.The open-loop control is driven by the double-step algorithm,resulting in a step response time of 0.41 ms and achieving a control bandwidth over 2 kHz.Additionally,the integrated angular sensor demonstrates a nonlinearity of 0.09%@±1.05 mrad,a sensitivity of 5.1 mV/(V∙mrad),and a minimum angular resolution of 0.3μrad.Under quasi-static driven conditions(500 Hz@±2 mrad),the maximum dynamic deformation of the mirror surface is merely 2 nm.
基金Supported by the Special Fund for Basic Scientific Research of Central-Level Public Welfare Scientific Research Institutes(2024-9007)。
文摘The accuracy of center height detection for corrugated beam guardrails is significantly affected by robot posture in the mobile highway guardrail detection systems based on structured light vision.To address the problem,this paper proposes an integrated calibration method for structured light vision sensors.In the proposed system,the sensor is mounted on a crawler-type mobile robot,which scans and measures the center height of guardrails while in motion.However,due to external disturbances such as uneven road surfaces and vehicle vibrations,the posture of the robot may deviate,causing displacement of the sensor platform and resulting in spatial 3D measurement errors.To overcome this issue,the system integrates inertial measurement unit(IMU)data into the sensor calibration process,enabling realtime correction of posture deviations through sensor fusion.This approach achieves a unified calibration of the structured light vision system,effectively compensates for posture-induced errors,and enhances detection accuracy.A prototype was developed and tested in both laboratory and real highway environments.Experimental results demonstrate that the proposed method enables accurate center height detection of guardrails under complex road conditions,significantly reduces posture-related measurement errors,and greatly improves the efficiency and reliability of traditional detection methods.
基金This work was supported by the National Key R&D Program of China(Grant No.2021YFB2802000)the National Natural Science Foundation of China(Grant Nos.61827826,62175086,62131018)+1 种基金the Natural Science Foundation of Jilin Province(Grant No.20220101107JC)the Education Department of Jilin Province(Grant No.JJKH20221003KJ).
文摘Since the invention of lasers,spatial-light-modulated laser processing has become a powerful tool for various applications.It enables multidimensional and dynamic modulation of the laser beam,which significantly improves the processing efficiency,accuracy,and flexibility,and presents wider prospects over traditional mechanical technologies for machining three-dimensional,hard,brittle,or transparent materials.In this review,we introduce:(1)The role of spatial light modulation technology in the development of femtosecond laser manufacturing;(2)the structured light generated by spatial light modulation and its generation methods;and(3)representative applications of spatial-light-modulated femtosecond laser manufacturing,including aberration correction,parallel processing,focal field engineering,and polarization control.Finally,we summarize the present challenges in the field and possible future research.
基金supported by the National Natural Science Foundation of China(Grant Nos.52105427,U2037205,52005041,51575053,and 51775047)Research Foundation from Ministry of Education of China(Grant No.6141A02033123)+2 种基金Beijing Municipal Commission of Education(Grant No.KM201910005003)Knowledge Innovation Program of Wuhan-Basic Research(Grant No.2022010801010349)Scientific Research Project of Hubei Provincial Department of Education(Grant No.B2022055)。
文摘Molybdenum disulfide(MoS_(2))-based nanostructures are highly desirable for applications such as chemical and biological sensing,photo/electrochemical catalysis,and energy storage due to their unique physical and chemical properties.In this work,MoS_(2)core-shell nanoparticles were first prepared through the liquid-phase processing of bulk MoS2by a femtosecond laser.The core of prepared nanoparticles was incompletely and weakly crystalline MoS_(2);the shell of prepared nanoparticles was highly crystalline MoS_(2),which wrapped around the core layer by layer.The femtosecond laser simultaneously achieved liquid-phase ablation and light exfoliation.The formation mechanism of the core-shell nanoparticles is to prepare the nanonuclei first by laser liquid-phase ablation and then the nanosheets by light exfoliation;the nanosheets will wrap the nanonuclei layer by layer through van der Waals forces to form core-shell nanoparticles.The MoS_(2)core-shell nanoparticles,because of Mo-S bond breakage and recombination,have high chemical activity for chemical catalysis.Afterward,the nanoparticles were used as a reducing agent to directly prepare three-dimensional(3D)Au-MoS_(2)micro/nanostructures,which were applied as surface-enhanced Raman spectroscopy(SERS)substrates to explore chemical sensing activity.The ultrahigh enhancement factor(1.06×10^(11)),ultralow detection limit(10-13M),and good SERS adaptability demonstrate highly sensitive SERS activity,great ability of ultralow concentration detection,and ability to detect diverse analytes,respectively.This work reveals the tremendous potential of 3D Au-MoS_(2)composite structures as excellent SERS substrates for chemical and biological sensing.
基金supported by the National Natural Science Foundation of China(Grant Nos.12204499 and 12174212)the Joint Key Projects of National Natural Science Foundation of China(Grant No.U2032206)。
文摘This paper presents an investigation of the secondary saturation characteristics of a HfTe_(2)saturable absorber.Pulse energies of 5.85 and 7.4 mJ were demonstrated with a high-order Hermite-Gaussian(HG)laser and a vortex laser,respectively,using alexandrite as the gain medium.To the best of our knowledge,these are the highest pulse energies directly generated with HG and vortex lasers.To broaden the applications of high-energy pulsed HG and vortex lasers,wavelength tuning in the region of 40 nm was achieved using an etalon.pulse energy of 5.85 mJ and a vortex laser with a single pulse energy of 7.4 mJ were obtained in alexandrite.The repetition rates of these lasers were 262 and 196 Hz,respectively.To expand the applications of high-energy structured lasers,wavelength tuning within the range of 747-787 nm was successfully accomplished using an etalon.
基金supported by the National Natural Science Foundation of China(Nos.92050202 and 12274299)the Science and Technology Commission of Shanghai Municipality(No.22QA1406600)the Natural Science Foundation of Shanghai(No.20ZR1437600).
文摘High-aspect-ratio structures with heights or depths significantly exceeding their lateral dimensions hold broad application potential across various fields.The production of these structures is challenging,requiring meticulous control over materials,scale,and precision.We introduce an economical and efficient approach for fabricating high-aspect-ratio nanostructures using a two-photon polymerization process.This approach achieves feature sizes of around 37 nm with an aspect ratio of 10:1 using commercial photoresists.Offering advantages over traditional techniques,our approach simplifies operation and enhances design flexibility,facilitating the creation of smaller,more complex,and high-aspect-ratio structures.The capabilities of this approach are demonstrated by producing arrays of three-dimensional microstructures that exhibit sub-micron scales,extensive periodicity,and pronounced aspect ratios.These developments open new possibilities for applications in biomedical,precision engineering,and optical microdevice manufacturing.
基金support by a project‘ReSoft’(SEN-13/2015)from the Research Council of Lithuaniasupport by JSPS Kakenhi Grant No.15K04637+1 种基金support via ARC Discovery DP120102980Gintas Šlekys for the partnership project with Altechna Ltd on industrial fs-laser fabrication.
文摘Processing of materials by ultrashort laser pulses has evolved significantly over the last decade and is starting to reveal its scientific,technological and industrial potential.In ultrafast laser manufacturing,optical energy of tightly focused femtosecond or picosecond laser pulses can be delivered to precisely defined positions in the bulk of materials via two-/multi-photon excitation on a timescale much faster than thermal energy exchange between photoexcited electrons and lattice ions.Control of photoionization and thermal processes with the highest precision,inducing local photomodification in sub-100-nm-sized regions has been achieved.State-of-the-art ultrashort laser processing techniques exploit high 0.1–1μm spatial resolution and almost unrestricted three-dimensional structuring capability.Adjustable pulse duration,spatiotemporal chirp,phase front tilt and polarization allow control of photomodification via uniquely wide parameter space.Mature opto-electrical/mechanical technologies have enabled laser processing speeds approaching meters-per-second,leading to a fast lab-to-fab transfer.The key aspects and latest achievements are reviewed with an emphasis on the fundamental relation between spatial resolution and total fabrication throughput.Emerging biomedical applications implementing micrometer feature precision over centimeter-scale scaffolds and photonic wire bonding in telecommunications are highlighted.
