In this paper, the optical/digital fringe multiplication (O/DFM) is realized in projection moiré using digital image processing (DIP). Both deformed grating and reference grating are captured using a CCD camera. ...In this paper, the optical/digital fringe multiplication (O/DFM) is realized in projection moiré using digital image processing (DIP). Both deformed grating and reference grating are captured using a CCD camera. The reference grating can also be produced using DIP. With the O/DFM, the pattern is multiplied with an image processing software, which is developed using MATLAB 6.5. Also with DIP, the phase shifting can become much simpler, and the automation can be adopted. The multiplied pattern is much thinner and easier to read, and sensitivity of measurement can be enhanced.展开更多
To achieve a low-complexity nonlinearity compensation(NLC)in high-symbol-rate(HSR)systems,we propose a modified weighted digital backpropagation(M-W-DBP)by jointly shifting the calculated position of nonlinear phase n...To achieve a low-complexity nonlinearity compensation(NLC)in high-symbol-rate(HSR)systems,we propose a modified weighted digital backpropagation(M-W-DBP)by jointly shifting the calculated position of nonlinear phase noise and considering the correlation of neighboring symbols in the NLC section of DBP.Based on this model,with the aid of neural network optimization,a learned version of M-W-DBP(M-W-LDBP)is also proposed and explored.Furthermore,enough technical details are revealed for the first time,including the principle of our proposed M-W-DBP and M-W-LDBP,the training process,and the complexity analysis of different DBPclass NLC algorithms.Evaluated numerically with QPSK,16QAM,and PS-64QAM modulation formats,1-step-per-span(1-StPS)M-W-DBP/LDBP achieves up to 1.29/1.49 dB and 0.63/0.74 dB signal-to-noise ratio improvement compared to chromatic dispersion compensation(CDC)in 90-GBaud and 128-GBaud 1000-km single-channel transmission systems,respectively.Moreover,1-StPS M-W-DBP/LDBP provides a more powerful NLC ability than 2-StPS LDBP but only needs about 60%of the complexity.The effectiveness of the proposed M-W-DBP and M-W-LDBP in the presence of laser phase noise is also verified and the necessity of using the learned version of M-WDBP is also discussed.This work is a comprehensive study of M-W-DBP/LDBP and other DBP-class NLC algorithms in HSR systems.展开更多
As a laser passes through a scattering medium,the light interacts with the irregular reflections within the medium,resulting in light scattering and the formation of speckles.In this paper,an image sensor based on the...As a laser passes through a scattering medium,the light interacts with the irregular reflections within the medium,resulting in light scattering and the formation of speckles.In this paper,an image sensor based on the combination of a coreless optical fiber and a digital camera is proposed for liquid refractive index sensing applications.The coreless fiber is used as a sensing unit,and the change in the speckle pattern is measured using the digital correlation method to detect the magnitude of the liquid's refractive index.The experimental results indicate that the laser image sensing technique is capable of effectively distinguishing liquid samples with refractive indices ranging from 1.332 8 to1.390 8,with a sensing sensitivity of-1.306 RIU-l.Moreover,the laser image sensing technique,with its advantages of high experimental reproducibility,simple system design,remote over-control,holds great research significance and potential application in laser communication and sensor integration.展开更多
We present a 1 × 4 Y-branch digital optical switch in which S-bend variable optical attenuators are integrated. The S-bend waveguides, which are always introduced to connect the switch and the standard fiber arra...We present a 1 × 4 Y-branch digital optical switch in which S-bend variable optical attenuators are integrated. The S-bend waveguides, which are always introduced to connect the switch and the standard fiber array, are made use of and designed as variable optical attenuators. A compact device with low crosstalk and larger branching-angle is obtained. The device is fabricated on the thermo-optic polymer materials,and the performance of the device is measured. With an applied driving power of less than 200mW, the device has a low crosstalk of less than - 35dB at a wavelength of 1.55 μm.展开更多
[Objective] The research aimed to study a paraffin method without using the microtome,and also introduced an analysis method for optical information of the plant anatomical digital photographs.[Method] The plant mater...[Objective] The research aimed to study a paraffin method without using the microtome,and also introduced an analysis method for optical information of the plant anatomical digital photographs.[Method] The plant material softened or not was embedded in paraffin according to the paraffin method.Cut the thin paraffin sections from the paraffin block with a sharp two-sided blade under anatomical lens.The thin material sections rolled up when they were cut off.Took the section rolls to a slide,and then heated them to melt the paraffin section roll.When the paraffin melted,the sections of plant material were rolled out.After the common or simplified procedures of staining and mounting,the preparations were finished.When an anatomical digital photograph was processed,copy it into the word file and two copies of the original photograph were obtained.One copy was selected to make it to be a negative photograph,and then press the key ＂Press Screen＂ to copy the screen frame.After it was copied into the word file,cut of the unnecessary parts and other operations were carried out,then processed photograph was obtained.[Results] The anatomical preparation for research was gotten.The analyzed digital photograph of the leaf structure of Salix matsudana var.matsudana f.tortuosa has some a three-dimensional effect,and the different leaf structures and cells,e.g.cuticle,cell wall,protoplast,vein,etc.can be identified easily.[Conclusion]The paraffin method without using the microtome has advantages of low cost and higher efficiency,which could be applied by the beginner or in the time without a microtome to be used.The analysis of the plant anatomical digital photographs can acquire more structural information than the original digital photographs,which shows the potentiality and prospects of the optical information analysis of the microscopic imagery and its digital photograph.展开更多
AIM:To evaluate the agreement of axial length(AL),anterior chamber parameters,and total cornea power obtained by swept-source optical coherence tomography(SS-OCT)-based and Scheimpflug-based optical biometers in myopi...AIM:To evaluate the agreement of axial length(AL),anterior chamber parameters,and total cornea power obtained by swept-source optical coherence tomography(SS-OCT)-based and Scheimpflug-based optical biometers in myopic children.METHODS:AL,steep keratometry(K),flat K,posterior corneal keratometry(PK),total keratometry(TK),anterior chamber depth(ACD),horizontal corneal diameter(CD),and central corneal thickness(CCT)were obtained using IOL Master 700 and Pentacam AXL.The agreement between the devices was evaluated using intraclass correlation coefficients(ICC),Bland-Altman plots,and astigmatism vector analysis.RESULTS:Totally 175 myopic children(48.5%male)with a mean age of 10.29±2.14y were enrolled.The ICC and Bland-Altman plots indicated a satisfactory agreement for AL,ACD,and CCT.The mean difference in CD of-0.31±0.30 mm was considered clinically significant(>0.2 mm).Additionally,measurements of K and TK obtained from the IOL Master 700 showed good agreement.Nevertheless,there were clinically significant differences observed in PK,simulated keratometry(simK),total cornea power,and astigmatism(at least 10%of the cases with a difference of>10 degrees in meridian)between the two devices.CONCLUSION:The study findings demonstrate a significant difference in K,PK,astigmatism,and CD,indicating that the two optical biometers cannot be considered interchangeable.Therefore,it is recommended to utilize one kind device for follow-up examinations in myopic children.展开更多
Scalability remains a major challenge in building practical fault-tolerant quantum computers.Currently,the largest number of qubits achieved across leading quantum platforms ranges from hundreds to thousands.In atom a...Scalability remains a major challenge in building practical fault-tolerant quantum computers.Currently,the largest number of qubits achieved across leading quantum platforms ranges from hundreds to thousands.In atom arrays,scalability is primarily constrained by the capacity to generate large numbers of optical tweezers,and conventional techniques using acousto-optic deflectors or spatial light modulators struggle to produce arrays much beyond∼10,000 tweezers.Moreover,these methods require additional microscope objectives to focus the light into micrometer-sized spots,which further complicates system integration and scalability.Here,we demonstrate the experimental generation of an optical tweezer array containing 280×280 spots using a metasurface,nearly an order of magnitude more than most existing systems.The metasurface leverages a large number of subwavelength phase-control pixels to engineer the wavefront of the incident light,enabling both large-scale tweezer generation and direct focusing into micron-scale spots without the need for a microscope.This result shifts the scalability bottleneck for atom arrays from the tweezer generation hardware to the available laser power.Furthermore,the array shows excellent intensity uniformity exceeding 90%,making it suitable for homogeneous single-atom loading and paving the way for trapping arrays of more than 10,000 atoms in the near future.展开更多
In the realm of secure information storage,optical encryption has emerged as a vital technique,particularly with the miniaturization of encryption devices.However,many existing systems lack the necessary reconfigurabi...In the realm of secure information storage,optical encryption has emerged as a vital technique,particularly with the miniaturization of encryption devices.However,many existing systems lack the necessary reconfigurability and dynamic functionality.This study presents a novel approach through the development of dynamic optical-to-chemical energy conversion metamaterials,which enable enhanced steganography and multilevel information storage.We introduce a micro-dynamic multiple encryption device that leverages programmable optical properties in coumarin-based metamaterials,achieved through a direct laser writing grayscale gradient strategy.This methodology allows for the dynamic regulation of photoluminescent characteristics and cross-linking networks,facilitating innovative steganographic techniques under varying light conditions.The integration of a multi-optical field control system enables real-time adjustments to the material’s properties,enhancing the device’s reconfigurability and storage capabilities.Our findings underscore the potential of these metamaterials in advancing the field of microscale optical encryption,paving the way for future applications in dynamic storage and information security.展开更多
In winter 2018,an aerosol physicochemical experiment was conducted in the Western Pacific Ocean(WPO)aboard the Research Vessel KEXUE of Chinese Academy of Sciences.This study systematically investigated both natural a...In winter 2018,an aerosol physicochemical experiment was conducted in the Western Pacific Ocean(WPO)aboard the Research Vessel KEXUE of Chinese Academy of Sciences.This study systematically investigated both natural and anthropogenic effects on marine aerosols optical properties,as well as the applicability of multi-satellite products and IMPROVE equation.The averaged aerosol optical depth(AOD500 nm)was 0.31±0.16 andÅngström exponent440–675 nm was 0.29±0.30.In offshore China,significant anthropogenic emissions affected the marine environment.In remote WPO,dust aerosols transported from northern China,Siberia,Central Asia,and those settling from the upper troposphere originating from north Africa,Arabian peninsula,and western India,were dominant.The spatial trends of AOD were opposite in the mid-latitude and southern seas of WPO.The highest AOD,0.32±0.23,appeared along the coast of South Asia at mid-latitude,decreasing from offshore seas to remote oceans.In low-latitude and equatorial seas,AOD significantly increased from coast to remote oceans.Ångström exponent dropped significantly from the coast to remote oceans as anthropogenic influence diminished across the entire WPO.Correlation analysis showed that both MODIS-C6 and Himawari AOD prod-ucts showed similar applicability in coastal urban areas,while Himawari AOD is highly recommended for coastal background and marine environment due to its finer resolution.The extinction coefficient derived from PM_(2.5) chemical compositions using IMPROVE algorithm exhibited a significant correlation(R^(2)=0.58)with the con-currently measured AOD in the absence of long-distance transport,suggesting that the IMPROVE is a reasonable proxy of the columnar average of marine aerosol extinctions free from transport influences.展开更多
The evolution of cities into digitally managed environments requires computational systems that can operate in real time while supporting predictive and adaptive infrastructure management.Earlier approaches have often...The evolution of cities into digitally managed environments requires computational systems that can operate in real time while supporting predictive and adaptive infrastructure management.Earlier approaches have often advanced one dimension—such as Internet of Things(IoT)-based data acquisition,Artificial Intelligence(AI)-driven analytics,or digital twin visualization—without fully integrating these strands into a single operational loop.As a result,many existing solutions encounter bottlenecks in responsiveness,interoperability,and scalability,while also leaving concerns about data privacy unresolved.This research introduces a hybrid AI–IoT–Digital Twin framework that combines continuous sensing,distributed intelligence,and simulation-based decision support.The design incorporates multi-source sensor data,lightweight edge inference through Convolutional Neural Networks(CNN)and Long ShortTerm Memory(LSTM)models,and federated learning enhanced with secure aggregation and differential privacy to maintain confidentiality.A digital twin layer extends these capabilities by simulating city assets such as traffic flows and water networks,generating what-if scenarios,and issuing actionable control signals.Complementary modules,including model compression and synchronization protocols,are embedded to ensure reliability in bandwidth-constrained and heterogeneous urban environments.The framework is validated in two urban domains:traffic management,where it adapts signal cycles based on real-time congestion patterns,and pipeline monitoring,where it anticipates leaks through pressure and vibration data.Experimental results show a 28%reduction in response time,a 35%decrease in maintenance costs,and a marked reduction in false positives relative to conventional baselines.The architecture also demonstrates stability across 50+edge devices under federated training and resilience to uneven node participation.The proposed system provides a scalable and privacy-aware foundation for predictive urban infrastructure management.By closing the loop between sensing,learning,and control,it reduces operator dependence,enhances resource efficiency,and supports transparent governance models for emerging smart cities.展开更多
Holography, which was invented by Dennis Gabor in 1948, offers an approach to reconstructing both the amplitude and phase information of a three-dimensional (3D) object [1]. Since its invention, the concept of hologra...Holography, which was invented by Dennis Gabor in 1948, offers an approach to reconstructing both the amplitude and phase information of a three-dimensional (3D) object [1]. Since its invention, the concept of holography has been widely used in various fields, such as microscopy [2], interferometry [3], ultrasonography [4], and holographic display [5]. Optical holography can be divided into two steps: recording and reconstruction. A conventional hologram is recorded onto a photosensitive film as the interference between an object beam carrying the 3D object information and a reference beam. Thereafter, the original object wavefront is reconstructed in the 3D image space by illuminating the reference beam on the recorded hologram.展开更多
The digital coherent detection technique has been investigated without any frequency-scanning device in the Brillouin optical time domain reflectometry （BOTDR）, where the simplex pulse codes are applied in the sensi...The digital coherent detection technique has been investigated without any frequency-scanning device in the Brillouin optical time domain reflectometry （BOTDR）, where the simplex pulse codes are applied in the sensing system. The time domain signal of every code sequence is collected by the data acquisition card （DAQ）. A shift-averaging technique is applied in the frequency domain for the reason that the local oscillator （LO） in the coherent detection is fix-frequency deviated from the primary source. With the 31-bit simplex code, the signal-to-noise ratio （SNR） has 3.5-dB enhancement with the same single pulse traces, accordant with the theoretical analysis. The frequency fluctuation for simplex codes is 14.01 MHz less than that for a single pulse as to 4-m spatial resolution. The results are believed to be beneficial for the BOTDR performance improvement.展开更多
We propose a novel high-performance digital optical sensor based on the Mach-Zehnder interferential effect and the dual-microring resonators with the waveguide-coupled feedback. The simulation results show that the se...We propose a novel high-performance digital optical sensor based on the Mach-Zehnder interferential effect and the dual-microring resonators with the waveguide-coupled feedback. The simulation results show that the sensitivity of the sensor can be orders of magnitude higher than that of aconventional sensor, and high quality factor is not critical in it. Moreover, by optimizing the length of the feedback waveguide to be equal to the perimeter of the ring, the measurement range of the proposed sensor is twice as much as that of the conventional sensor in the weak coupling case.展开更多
We present an optical encryption method of multiple three-dimensional objects based on multiple interferences and single-pixel digital holography. By modifying the Mach-Zehnder interferometer, the interference of the ...We present an optical encryption method of multiple three-dimensional objects based on multiple interferences and single-pixel digital holography. By modifying the Mach-Zehnder interferometer, the interference of the multiple objects beams and the one reference beam is used to simultaneously encrypt multiple objects into a ciphertext. During decryption, each three-dimensional object can be decrypted independently without having to decrypt other objects. Since the single- pixel digital holography based on compressive sensing theory is introduced, the encrypted data of this method is effectively reduced. In addition, recording fewer encrypted data can greatly reduce the bandwidth of network transmission. Moreover, the compressive sensing essentially serves as a secret key that makes an intruder attack invalid, which means that the system is more secure than the conventional encryption method. Simulation results demonstrate the feasibility of the proposed method and show that the system has good security performance.展开更多
Urdu,a prominent subcontinental language,serves as a versatile means of communication.However,its handwritten expressions present challenges for optical character recognition(OCR).While various OCR techniques have bee...Urdu,a prominent subcontinental language,serves as a versatile means of communication.However,its handwritten expressions present challenges for optical character recognition(OCR).While various OCR techniques have been proposed,most of them focus on recognizing printed Urdu characters and digits.To the best of our knowledge,very little research has focused solely on Urdu pure handwriting recognition,and the results of such proposed methods are often inadequate.In this study,we introduce a novel approach to recognizing Urdu pure handwritten digits and characters using Convolutional Neural Networks(CNN).Our proposed method utilizes convolutional layers to extract important features from input images and classifies them using fully connected layers,enabling efficient and accurate detection of Urdu handwritten digits and characters.We implemented the proposed technique on a large publicly available dataset of Urdu handwritten digits and characters.The findings demonstrate that the CNN model achieves an accuracy of 98.30%and an F1 score of 88.6%,indicating its effectiveness in detecting and classifyingUrdu handwritten digits and characters.These results have far-reaching implications for various applications,including document analysis,text recognition,and language understanding,which have previously been unexplored in the context of Urdu handwriting data.This work lays a solid foundation for future research and development in Urdu language detection and processing,opening up new opportunities for advancement in this field.展开更多
Intelligent assembly of large-scale,complex structures using an intelligent manufacturing platform represents the future development direction for industrial manufacturing.During large-scale structural assembly proces...Intelligent assembly of large-scale,complex structures using an intelligent manufacturing platform represents the future development direction for industrial manufacturing.During large-scale structural assembly processes,several bottleneck problems occur in the existing auxiliary assembly technology.First,the traditional LiDARbased assembly technology is often limited by the openness of the manufacturing environment,in which there are blind spots,and continuous online assembly adjustment thus cannot be realized.Second,for assembly of large structures,a single-station LiDAR system cannot achieve complete coverage,which means that a multi-station combination method must be used to acquire the complete three-dimensional data;many more data errors are caused by the transfer between stations than by the measurement accuracy of a single station,which means that the overall system's measurement and adjustment errors are increased greatly.Third,because of the large numbers of structural components contained in a large assembly,the accumulated errors may lead to assembly interference,but the LiDAR-assisted assembly process does not have a feedback perception capability,and thus assembly component loss can easily be caused when assembly interference occurs.Therefore,this paper proposes to combine an optical fiber sensor network with digital twin technology,which will allow the test data from the assembly entity state in the real world to be applied to the"twin"model in the virtual world and thus solve the problems with test openness and data transfer.The problem of station and perception feedback is also addressed and represents the main innovation of this work.The system uses an optical fiber sensor network as a flexible sensing medium to monitor the strain field distribution within a complex area in real time,and then completes real-time parameter adjustment of the virtual assembly based on the distributed data.Complex areas include areas that are laser-unreachable,areas with complex contact surfaces,and areas with large-scale bending deformations.An assembly condition monitoring system is designed based on the optical fiber sensor network,and an assembly condition monitoring algorithm based on multiple physical quantities is proposed.The feasibility of use of the optical fiber sensor network as the real-state parameter acquisition module for the digital twin intelligent assembly system is discussed.The offset of any position in the test area is calculated using the convolutional neural network of a residual module to provide the compensation parameters required for the virtual model of the assembly structure.In the model optimization parameter module,a correction data table is obtained through iterative learning of the algorithm to realize state prediction from the test data.The experiment simulates a largescale structure assembly process,and performs virtual and real mapping for a variety of situations with different assembly errors to enable correction of the digital twin data stream for the assembly process through the optical fiber sensor network.In the plane strain field calibration experiment,the maximum error among the test values for this system is 0.032 mm,and the average error is 0.014 mm.The results show that use of visual calibration can correct the test error to within a very small range.This result is equally applicable to gradient curvature surfaces and freeform surfaces.Statistics show that the average measurement accuracy error for regular surfaces is better than 11.2%,and the average measurement accuracy error for irregular surfaces is better than 14.8%.During simulation of large-scale structure assembly experiments,the average position deviation accuracy is 0.043 mm,which is in line with the designed accuracy.展开更多
Chaotic optical communication has shown large potential as a hardware encryption method in the physical layer.As an important figure of merit,the bit rate–distance product of chaotic optical communication has been co...Chaotic optical communication has shown large potential as a hardware encryption method in the physical layer.As an important figure of merit,the bit rate–distance product of chaotic optical communication has been continually improved to 30 Gb/s×340 km,but it is still far from the requirement for a deployed optical fiber communication system,which is beyond 100 Gb/s×1000 km.A chaotic carrier can be considered as an analog signal and suffers from fiber channel impairments,limiting the transmission distance of high-speed chaotic optical communications.To break the limit,we propose and experimentally demonstrate a pilot-based digital signal processing scheme for coherent chaotic optical communication combined with deep-learning-based chaotic synchronization.Both transmission impairment recovery and chaotic synchronization are realized in the digital domain.The frequency offset of the lasers is accurately estimated and compensated by determining the location of the pilot tone in the frequency domain,and the equalization and phase noise compensation are jointly performed by the least mean square algorithm through the time domain pilot symbols.Using the proposed method,100 Gb∕s chaotically encrypted quadrature phase-shift keying(QPSK)signal over 800 km single-mode fiber(SMF)transmission is experimentally demonstrated.In order to enhance security,40 Gb∕s real-time chaotically encrypted QPSK signal over 800 km SMF transmission is realized by inserting pilot symbols and tone in a field-programmable gate array.This method provides a feasible approach to promote the practical application of chaotic optical communications and guarantees the high security of chaotic encryption.展开更多
The characteristics of optical fiber are quite important for improving the performance of optical fiber communication and sensor systems.Based on the Mach-Zehnder interferometer,a new measuring method is proposed and ...The characteristics of optical fiber are quite important for improving the performance of optical fiber communication and sensor systems.Based on the Mach-Zehnder interferometer,a new measuring method is proposed and the digital holograms between the single mode fibers(SMFs) and specialty double-cladding(DC) fibers are analyzed.The experimental results show that the fringe density can be changed under the conditions of coaxial and off-axial interferences.Therefore it can be used to analyze the optical fiber characteristics including refractive index distribution,fiber modes,phase difference,etc.展开更多
There is a certain failure rate in traditional glaucoma surgery because of the lack of depth information in microscope images.In this work,we present a digital microscope-integrated optical coherence tomography(MIOCT)...There is a certain failure rate in traditional glaucoma surgery because of the lack of depth information in microscope images.In this work,we present a digital microscope-integrated optical coherence tomography(MIOCT)system and several custom-made OCT-compatible instruments for glaucoma surgery.Sixteen ophthalmologists were asked to perform trabeculectomy and canaloplasty on live porcine eyes using the system and instruments.After surgery,a subjective feedback survey about the user experience was taken.The experiment results showed that our system can help surgeons easily locate important tissue structures during surgery.The custom-made instruments also solved the shadowing problem in OCT imaging.Surgeons preferred to use the system in their future practice.展开更多
文摘In this paper, the optical/digital fringe multiplication (O/DFM) is realized in projection moiré using digital image processing (DIP). Both deformed grating and reference grating are captured using a CCD camera. The reference grating can also be produced using DIP. With the O/DFM, the pattern is multiplied with an image processing software, which is developed using MATLAB 6.5. Also with DIP, the phase shifting can become much simpler, and the automation can be adopted. The multiplied pattern is much thinner and easier to read, and sensitivity of measurement can be enhanced.
基金supported in part by National Natural Science Foundation of China(No.62271080)in part by Fund of State Key Laboratory of IPOC(BUPT)(No.IPOC2022ZT06)in part by BUPT Excellent Ph.D Students Foundation(No.CX2022102).
文摘To achieve a low-complexity nonlinearity compensation(NLC)in high-symbol-rate(HSR)systems,we propose a modified weighted digital backpropagation(M-W-DBP)by jointly shifting the calculated position of nonlinear phase noise and considering the correlation of neighboring symbols in the NLC section of DBP.Based on this model,with the aid of neural network optimization,a learned version of M-W-DBP(M-W-LDBP)is also proposed and explored.Furthermore,enough technical details are revealed for the first time,including the principle of our proposed M-W-DBP and M-W-LDBP,the training process,and the complexity analysis of different DBPclass NLC algorithms.Evaluated numerically with QPSK,16QAM,and PS-64QAM modulation formats,1-step-per-span(1-StPS)M-W-DBP/LDBP achieves up to 1.29/1.49 dB and 0.63/0.74 dB signal-to-noise ratio improvement compared to chromatic dispersion compensation(CDC)in 90-GBaud and 128-GBaud 1000-km single-channel transmission systems,respectively.Moreover,1-StPS M-W-DBP/LDBP provides a more powerful NLC ability than 2-StPS LDBP but only needs about 60%of the complexity.The effectiveness of the proposed M-W-DBP and M-W-LDBP in the presence of laser phase noise is also verified and the necessity of using the learned version of M-WDBP is also discussed.This work is a comprehensive study of M-W-DBP/LDBP and other DBP-class NLC algorithms in HSR systems.
文摘As a laser passes through a scattering medium,the light interacts with the irregular reflections within the medium,resulting in light scattering and the formation of speckles.In this paper,an image sensor based on the combination of a coreless optical fiber and a digital camera is proposed for liquid refractive index sensing applications.The coreless fiber is used as a sensing unit,and the change in the speckle pattern is measured using the digital correlation method to detect the magnitude of the liquid's refractive index.The experimental results indicate that the laser image sensing technique is capable of effectively distinguishing liquid samples with refractive indices ranging from 1.332 8 to1.390 8,with a sensing sensitivity of-1.306 RIU-l.Moreover,the laser image sensing technique,with its advantages of high experimental reproducibility,simple system design,remote over-control,holds great research significance and potential application in laser communication and sensor integration.
文摘We present a 1 × 4 Y-branch digital optical switch in which S-bend variable optical attenuators are integrated. The S-bend waveguides, which are always introduced to connect the switch and the standard fiber array, are made use of and designed as variable optical attenuators. A compact device with low crosstalk and larger branching-angle is obtained. The device is fabricated on the thermo-optic polymer materials,and the performance of the device is measured. With an applied driving power of less than 200mW, the device has a low crosstalk of less than - 35dB at a wavelength of 1.55 μm.
基金Supported by National Natural Science Foundation of China(30770124)~~
文摘[Objective] The research aimed to study a paraffin method without using the microtome,and also introduced an analysis method for optical information of the plant anatomical digital photographs.[Method] The plant material softened or not was embedded in paraffin according to the paraffin method.Cut the thin paraffin sections from the paraffin block with a sharp two-sided blade under anatomical lens.The thin material sections rolled up when they were cut off.Took the section rolls to a slide,and then heated them to melt the paraffin section roll.When the paraffin melted,the sections of plant material were rolled out.After the common or simplified procedures of staining and mounting,the preparations were finished.When an anatomical digital photograph was processed,copy it into the word file and two copies of the original photograph were obtained.One copy was selected to make it to be a negative photograph,and then press the key ＂Press Screen＂ to copy the screen frame.After it was copied into the word file,cut of the unnecessary parts and other operations were carried out,then processed photograph was obtained.[Results] The anatomical preparation for research was gotten.The analyzed digital photograph of the leaf structure of Salix matsudana var.matsudana f.tortuosa has some a three-dimensional effect,and the different leaf structures and cells,e.g.cuticle,cell wall,protoplast,vein,etc.can be identified easily.[Conclusion]The paraffin method without using the microtome has advantages of low cost and higher efficiency,which could be applied by the beginner or in the time without a microtome to be used.The analysis of the plant anatomical digital photographs can acquire more structural information than the original digital photographs,which shows the potentiality and prospects of the optical information analysis of the microscopic imagery and its digital photograph.
基金Supported by National Natural Science Foundation of Guangdong,China(No.2020A1515010829,No.2023A1515011652,No.2025A1515012389)Science and Technology Program of Guangzhou,China(No.2025A03J4033).
文摘AIM:To evaluate the agreement of axial length(AL),anterior chamber parameters,and total cornea power obtained by swept-source optical coherence tomography(SS-OCT)-based and Scheimpflug-based optical biometers in myopic children.METHODS:AL,steep keratometry(K),flat K,posterior corneal keratometry(PK),total keratometry(TK),anterior chamber depth(ACD),horizontal corneal diameter(CD),and central corneal thickness(CCT)were obtained using IOL Master 700 and Pentacam AXL.The agreement between the devices was evaluated using intraclass correlation coefficients(ICC),Bland-Altman plots,and astigmatism vector analysis.RESULTS:Totally 175 myopic children(48.5%male)with a mean age of 10.29±2.14y were enrolled.The ICC and Bland-Altman plots indicated a satisfactory agreement for AL,ACD,and CCT.The mean difference in CD of-0.31±0.30 mm was considered clinically significant(>0.2 mm).Additionally,measurements of K and TK obtained from the IOL Master 700 showed good agreement.Nevertheless,there were clinically significant differences observed in PK,simulated keratometry(simK),total cornea power,and astigmatism(at least 10%of the cases with a difference of>10 degrees in meridian)between the two devices.CONCLUSION:The study findings demonstrate a significant difference in K,PK,astigmatism,and CD,indicating that the two optical biometers cannot be considered interchangeable.Therefore,it is recommended to utilize one kind device for follow-up examinations in myopic children.
基金supported by the National Natural Science Foundation of China (Grant No.92576208)Tsinghua University Initiative Scientific Research Program+1 种基金Beijing Science and Technology Planning ProjectTsinghua University Dushi Program。
文摘Scalability remains a major challenge in building practical fault-tolerant quantum computers.Currently,the largest number of qubits achieved across leading quantum platforms ranges from hundreds to thousands.In atom arrays,scalability is primarily constrained by the capacity to generate large numbers of optical tweezers,and conventional techniques using acousto-optic deflectors or spatial light modulators struggle to produce arrays much beyond∼10,000 tweezers.Moreover,these methods require additional microscope objectives to focus the light into micrometer-sized spots,which further complicates system integration and scalability.Here,we demonstrate the experimental generation of an optical tweezer array containing 280×280 spots using a metasurface,nearly an order of magnitude more than most existing systems.The metasurface leverages a large number of subwavelength phase-control pixels to engineer the wavefront of the incident light,enabling both large-scale tweezer generation and direct focusing into micron-scale spots without the need for a microscope.This result shifts the scalability bottleneck for atom arrays from the tweezer generation hardware to the available laser power.Furthermore,the array shows excellent intensity uniformity exceeding 90%,making it suitable for homogeneous single-atom loading and paving the way for trapping arrays of more than 10,000 atoms in the near future.
基金the National Key R&D Program of China(Project No.2022YFB4700100)National Natural Science Foundation of China(Grant Nos.61973298)+2 种基金Hong Kong Research Grants Council(GRF Project Number 11216120)the CAS-RGC Joint Laboratory Funding Scheme(Project Number JLFS/E-104/18)the Innovation Promotion Research Association of the Chinese Academy of Sciences(NO.2022199)。
文摘In the realm of secure information storage,optical encryption has emerged as a vital technique,particularly with the miniaturization of encryption devices.However,many existing systems lack the necessary reconfigurability and dynamic functionality.This study presents a novel approach through the development of dynamic optical-to-chemical energy conversion metamaterials,which enable enhanced steganography and multilevel information storage.We introduce a micro-dynamic multiple encryption device that leverages programmable optical properties in coumarin-based metamaterials,achieved through a direct laser writing grayscale gradient strategy.This methodology allows for the dynamic regulation of photoluminescent characteristics and cross-linking networks,facilitating innovative steganographic techniques under varying light conditions.The integration of a multi-optical field control system enables real-time adjustments to the material’s properties,enhancing the device’s reconfigurability and storage capabilities.Our findings underscore the potential of these metamaterials in advancing the field of microscale optical encryption,paving the way for future applications in dynamic storage and information security.
基金supported by the CAS Strategic Priority Research Program(No.XDB0760102),the Ministry of Science and Technology of China(No.2022YFF0802501)the Major Science and Technology Infrastructure Maintenance and Transformation Project of the Chinese Academy of Sciences,Shanghai Science and Technology Innovation Action Plan-Phospherus Project(No.23YF1426200)the National Key Research and Development Program of China(No.2024YFE0212200).
文摘In winter 2018,an aerosol physicochemical experiment was conducted in the Western Pacific Ocean(WPO)aboard the Research Vessel KEXUE of Chinese Academy of Sciences.This study systematically investigated both natural and anthropogenic effects on marine aerosols optical properties,as well as the applicability of multi-satellite products and IMPROVE equation.The averaged aerosol optical depth(AOD500 nm)was 0.31±0.16 andÅngström exponent440–675 nm was 0.29±0.30.In offshore China,significant anthropogenic emissions affected the marine environment.In remote WPO,dust aerosols transported from northern China,Siberia,Central Asia,and those settling from the upper troposphere originating from north Africa,Arabian peninsula,and western India,were dominant.The spatial trends of AOD were opposite in the mid-latitude and southern seas of WPO.The highest AOD,0.32±0.23,appeared along the coast of South Asia at mid-latitude,decreasing from offshore seas to remote oceans.In low-latitude and equatorial seas,AOD significantly increased from coast to remote oceans.Ångström exponent dropped significantly from the coast to remote oceans as anthropogenic influence diminished across the entire WPO.Correlation analysis showed that both MODIS-C6 and Himawari AOD prod-ucts showed similar applicability in coastal urban areas,while Himawari AOD is highly recommended for coastal background and marine environment due to its finer resolution.The extinction coefficient derived from PM_(2.5) chemical compositions using IMPROVE algorithm exhibited a significant correlation(R^(2)=0.58)with the con-currently measured AOD in the absence of long-distance transport,suggesting that the IMPROVE is a reasonable proxy of the columnar average of marine aerosol extinctions free from transport influences.
基金The researchers would like to thank the Deanship of Graduate Studies and Scientific Research at Qassim University for financial support(QU-APC-2025)。
文摘The evolution of cities into digitally managed environments requires computational systems that can operate in real time while supporting predictive and adaptive infrastructure management.Earlier approaches have often advanced one dimension—such as Internet of Things(IoT)-based data acquisition,Artificial Intelligence(AI)-driven analytics,or digital twin visualization—without fully integrating these strands into a single operational loop.As a result,many existing solutions encounter bottlenecks in responsiveness,interoperability,and scalability,while also leaving concerns about data privacy unresolved.This research introduces a hybrid AI–IoT–Digital Twin framework that combines continuous sensing,distributed intelligence,and simulation-based decision support.The design incorporates multi-source sensor data,lightweight edge inference through Convolutional Neural Networks(CNN)and Long ShortTerm Memory(LSTM)models,and federated learning enhanced with secure aggregation and differential privacy to maintain confidentiality.A digital twin layer extends these capabilities by simulating city assets such as traffic flows and water networks,generating what-if scenarios,and issuing actionable control signals.Complementary modules,including model compression and synchronization protocols,are embedded to ensure reliability in bandwidth-constrained and heterogeneous urban environments.The framework is validated in two urban domains:traffic management,where it adapts signal cycles based on real-time congestion patterns,and pipeline monitoring,where it anticipates leaks through pressure and vibration data.Experimental results show a 28%reduction in response time,a 35%decrease in maintenance costs,and a marked reduction in false positives relative to conventional baselines.The architecture also demonstrates stability across 50+edge devices under federated training and resilience to uneven node participation.The proposed system provides a scalable and privacy-aware foundation for predictive urban infrastructure management.By closing the loop between sensing,learning,and control,it reduces operator dependence,enhances resource efficiency,and supports transparent governance models for emerging smart cities.
基金support from the Australian Research Council (ARC) through the Discovery Project (DP180102402)support from a scholarship from theChina Scholarship Council (201706190189)financial support from the Humboldt Research Fellowship from the Alexander von Humboldt Foundation
文摘Holography, which was invented by Dennis Gabor in 1948, offers an approach to reconstructing both the amplitude and phase information of a three-dimensional (3D) object [1]. Since its invention, the concept of holography has been widely used in various fields, such as microscopy [2], interferometry [3], ultrasonography [4], and holographic display [5]. Optical holography can be divided into two steps: recording and reconstruction. A conventional hologram is recorded onto a photosensitive film as the interference between an object beam carrying the 3D object information and a reference beam. Thereafter, the original object wavefront is reconstructed in the 3D image space by illuminating the reference beam on the recorded hologram.
基金supported by the National High Technology Research and Development Program of China(Grant No.2012AA041203)the National Natural Science Foundation of China(Grant Nos.61377062 and 31201377)+1 种基金the Program of Shanghai Excellent Technical Leaders,China(Grant No.13XD1425400)the Doctorial Fund of Zhengzhou University of Light Industry,China(Grant No.2013BSJJ012)
文摘The digital coherent detection technique has been investigated without any frequency-scanning device in the Brillouin optical time domain reflectometry （BOTDR）, where the simplex pulse codes are applied in the sensing system. The time domain signal of every code sequence is collected by the data acquisition card （DAQ）. A shift-averaging technique is applied in the frequency domain for the reason that the local oscillator （LO） in the coherent detection is fix-frequency deviated from the primary source. With the 31-bit simplex code, the signal-to-noise ratio （SNR） has 3.5-dB enhancement with the same single pulse traces, accordant with the theoretical analysis. The frequency fluctuation for simplex codes is 14.01 MHz less than that for a single pulse as to 4-m spatial resolution. The results are believed to be beneficial for the BOTDR performance improvement.
基金Project supported by the National Basic Research Program of China(Grant No.2010CB327601)
文摘We propose a novel high-performance digital optical sensor based on the Mach-Zehnder interferential effect and the dual-microring resonators with the waveguide-coupled feedback. The simulation results show that the sensitivity of the sensor can be orders of magnitude higher than that of aconventional sensor, and high quality factor is not critical in it. Moreover, by optimizing the length of the feedback waveguide to be equal to the perimeter of the ring, the measurement range of the proposed sensor is twice as much as that of the conventional sensor in the weak coupling case.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61405130 and 61320106015)
文摘We present an optical encryption method of multiple three-dimensional objects based on multiple interferences and single-pixel digital holography. By modifying the Mach-Zehnder interferometer, the interference of the multiple objects beams and the one reference beam is used to simultaneously encrypt multiple objects into a ciphertext. During decryption, each three-dimensional object can be decrypted independently without having to decrypt other objects. Since the single- pixel digital holography based on compressive sensing theory is introduced, the encrypted data of this method is effectively reduced. In addition, recording fewer encrypted data can greatly reduce the bandwidth of network transmission. Moreover, the compressive sensing essentially serves as a secret key that makes an intruder attack invalid, which means that the system is more secure than the conventional encryption method. Simulation results demonstrate the feasibility of the proposed method and show that the system has good security performance.
文摘Urdu,a prominent subcontinental language,serves as a versatile means of communication.However,its handwritten expressions present challenges for optical character recognition(OCR).While various OCR techniques have been proposed,most of them focus on recognizing printed Urdu characters and digits.To the best of our knowledge,very little research has focused solely on Urdu pure handwriting recognition,and the results of such proposed methods are often inadequate.In this study,we introduce a novel approach to recognizing Urdu pure handwritten digits and characters using Convolutional Neural Networks(CNN).Our proposed method utilizes convolutional layers to extract important features from input images and classifies them using fully connected layers,enabling efficient and accurate detection of Urdu handwritten digits and characters.We implemented the proposed technique on a large publicly available dataset of Urdu handwritten digits and characters.The findings demonstrate that the CNN model achieves an accuracy of 98.30%and an F1 score of 88.6%,indicating its effectiveness in detecting and classifyingUrdu handwritten digits and characters.These results have far-reaching implications for various applications,including document analysis,text recognition,and language understanding,which have previously been unexplored in the context of Urdu handwriting data.This work lays a solid foundation for future research and development in Urdu language detection and processing,opening up new opportunities for advancement in this field.
基金supported by the National Science Foundation of China(Theoretical Model and Experimental Research on the Novel FBG Sensing System based on the Fusion Algorithm,No.61703056)the Jilin Province Science and Technology Development Plan Project(No.20190103154JH)。
文摘Intelligent assembly of large-scale,complex structures using an intelligent manufacturing platform represents the future development direction for industrial manufacturing.During large-scale structural assembly processes,several bottleneck problems occur in the existing auxiliary assembly technology.First,the traditional LiDARbased assembly technology is often limited by the openness of the manufacturing environment,in which there are blind spots,and continuous online assembly adjustment thus cannot be realized.Second,for assembly of large structures,a single-station LiDAR system cannot achieve complete coverage,which means that a multi-station combination method must be used to acquire the complete three-dimensional data;many more data errors are caused by the transfer between stations than by the measurement accuracy of a single station,which means that the overall system's measurement and adjustment errors are increased greatly.Third,because of the large numbers of structural components contained in a large assembly,the accumulated errors may lead to assembly interference,but the LiDAR-assisted assembly process does not have a feedback perception capability,and thus assembly component loss can easily be caused when assembly interference occurs.Therefore,this paper proposes to combine an optical fiber sensor network with digital twin technology,which will allow the test data from the assembly entity state in the real world to be applied to the"twin"model in the virtual world and thus solve the problems with test openness and data transfer.The problem of station and perception feedback is also addressed and represents the main innovation of this work.The system uses an optical fiber sensor network as a flexible sensing medium to monitor the strain field distribution within a complex area in real time,and then completes real-time parameter adjustment of the virtual assembly based on the distributed data.Complex areas include areas that are laser-unreachable,areas with complex contact surfaces,and areas with large-scale bending deformations.An assembly condition monitoring system is designed based on the optical fiber sensor network,and an assembly condition monitoring algorithm based on multiple physical quantities is proposed.The feasibility of use of the optical fiber sensor network as the real-state parameter acquisition module for the digital twin intelligent assembly system is discussed.The offset of any position in the test area is calculated using the convolutional neural network of a residual module to provide the compensation parameters required for the virtual model of the assembly structure.In the model optimization parameter module,a correction data table is obtained through iterative learning of the algorithm to realize state prediction from the test data.The experiment simulates a largescale structure assembly process,and performs virtual and real mapping for a variety of situations with different assembly errors to enable correction of the digital twin data stream for the assembly process through the optical fiber sensor network.In the plane strain field calibration experiment,the maximum error among the test values for this system is 0.032 mm,and the average error is 0.014 mm.The results show that use of visual calibration can correct the test error to within a very small range.This result is equally applicable to gradient curvature surfaces and freeform surfaces.Statistics show that the average measurement accuracy error for regular surfaces is better than 11.2%,and the average measurement accuracy error for irregular surfaces is better than 14.8%.During simulation of large-scale structure assembly experiments,the average position deviation accuracy is 0.043 mm,which is in line with the designed accuracy.
基金supported by the National Nature Science Foundation of China (Grant No.62025503).
文摘Chaotic optical communication has shown large potential as a hardware encryption method in the physical layer.As an important figure of merit,the bit rate–distance product of chaotic optical communication has been continually improved to 30 Gb/s×340 km,but it is still far from the requirement for a deployed optical fiber communication system,which is beyond 100 Gb/s×1000 km.A chaotic carrier can be considered as an analog signal and suffers from fiber channel impairments,limiting the transmission distance of high-speed chaotic optical communications.To break the limit,we propose and experimentally demonstrate a pilot-based digital signal processing scheme for coherent chaotic optical communication combined with deep-learning-based chaotic synchronization.Both transmission impairment recovery and chaotic synchronization are realized in the digital domain.The frequency offset of the lasers is accurately estimated and compensated by determining the location of the pilot tone in the frequency domain,and the equalization and phase noise compensation are jointly performed by the least mean square algorithm through the time domain pilot symbols.Using the proposed method,100 Gb∕s chaotically encrypted quadrature phase-shift keying(QPSK)signal over 800 km single-mode fiber(SMF)transmission is experimentally demonstrated.In order to enhance security,40 Gb∕s real-time chaotically encrypted QPSK signal over 800 km SMF transmission is realized by inserting pilot symbols and tone in a field-programmable gate array.This method provides a feasible approach to promote the practical application of chaotic optical communications and guarantees the high security of chaotic encryption.
基金supported by the Key Program of the National Natural Science Foundation of China (No.60937003)the Science and Technology Commission of Shanghai Municipality (STCSM) (No.0952nm06800)
文摘The characteristics of optical fiber are quite important for improving the performance of optical fiber communication and sensor systems.Based on the Mach-Zehnder interferometer,a new measuring method is proposed and the digital holograms between the single mode fibers(SMFs) and specialty double-cladding(DC) fibers are analyzed.The experimental results show that the fringe density can be changed under the conditions of coaxial and off-axial interferences.Therefore it can be used to analyze the optical fiber characteristics including refractive index distribution,fiber modes,phase difference,etc.
基金support of the foundations:National Key R&D Program of China,Grant Nos.2022YFC2404201CAS Project for Young Scientists in Basic Research,Grant Nos.YSBR-067+2 种基金The Gusu Innovation and Entrepreneurship Leading Talents in Suzhou City,Grant Nos.ZXL2021425Jiangsu Science and Technology Plan Program,Grant Nos.BK20220263National Key R&D Program of China,Grant Nos.2021YFF0700503.
文摘There is a certain failure rate in traditional glaucoma surgery because of the lack of depth information in microscope images.In this work,we present a digital microscope-integrated optical coherence tomography(MIOCT)system and several custom-made OCT-compatible instruments for glaucoma surgery.Sixteen ophthalmologists were asked to perform trabeculectomy and canaloplasty on live porcine eyes using the system and instruments.After surgery,a subjective feedback survey about the user experience was taken.The experiment results showed that our system can help surgeons easily locate important tissue structures during surgery.The custom-made instruments also solved the shadowing problem in OCT imaging.Surgeons preferred to use the system in their future practice.
