The effective detection depth of the needle-like optical probe is studied. The light transport model in highly scattering tissue is the diffusion equation and the boundary is Neuman. The sensitivity matrix is related ...The effective detection depth of the needle-like optical probe is studied. The light transport model in highly scattering tissue is the diffusion equation and the boundary is Neuman. The sensitivity matrix is related to the position of the light source and the detector. It can be used to evaluate the effective detection depth. The sensitivity matrix is defined as the multiplication of the source and detector hght distribution. Six different groups about ix parameters including the source diameter and detector fibers, the core-to-core distance between the source and detector fibers, the opotode depth, the absorption, and reduced scattering coefficient, are used as experimental models. The relationship between the six parameters and the effective detection depth is analyzed. Resuits can be used to study the spatial resolution and the depth of multi-fibers.展开更多
Infrared signal detection is widely used in many fields.Due to the detection principle,however,the accuracy and range of detection are limited.Thanks to the ultra stability of the^(87)Sr optical lattice clock,external...Infrared signal detection is widely used in many fields.Due to the detection principle,however,the accuracy and range of detection are limited.Thanks to the ultra stability of the^(87)Sr optical lattice clock,external infrared electromagnetic wave disturbances can be responded to.Utilizing the ac Stark shift of the clock transition,we propose a new method to detect infrared signals.According to our calculations,the theoretical detection accuracy in the vicinity of its resonance band of 2.6μm can reach the order of 10-14W,while the minimum detectable signal of common detectors is on the order of 10^(-10)W.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
The optical wireless communication (OWC) is afading channel because of the effect of atmosphericattenuation. We introduce a cumulant-based adaptive detection technique to providehigh performance for OWC. The received ...The optical wireless communication (OWC) is afading channel because of the effect of atmosphericattenuation. We introduce a cumulant-based adaptive detection technique to providehigh performance for OWC. The received signalof OWC over strong turbulence channels is assumedto be a mixture of K-distributed fading andGaussian distributed thermal noise. In order tomitigate the fading induced by turbulence, thedecision threshold-updating algorithm based onsecond and higher order cumulants is proposed,which is able to operate in an unknown turbulenceenvironment. The performance of the adaptiveprocessing scheme has been evaluated by meansof Monte Carlo simulations. It is shown that theproposed approach proves valuable for a limitednumber K of memory data.展开更多
The measurement and control of high temperature play very important roles in national defense,military,scientific experiments,industrial and agricultural production.Photoelectric pyrometer is one of the important radi...The measurement and control of high temperature play very important roles in national defense,military,scientific experiments,industrial and agricultural production.Photoelectric pyrometer is one of the important radiation thermometers for non-contact temperature measurement.It has an important application in the field of high temperature measurement,and its performance directly affects the accuracy of temperature measurement.By improving the design of the detection optical system of the photoelectric pyrometer,the imaging performance of the photoelectric pyrometer can be improved effectively,and the temperature measurement accuracy can be improved.In this paper,the temperature measurement principle of photoelectric pyrometer,the wo rking principle of the detection optical system and the composition of the system are introduced.The optical components that affect the imaging of the optical system of the photoelectric pyrometer are analyzed.The optical pyrometer detection optical system is simulated by ZEMAX software,based on the analysis results,the Modulation Transfer Function(MTF)and the spot Diagram are used as the main evaluation criteria to optimize the design of the objective lens of the photoelectric pyrometer detection optical system.The imaging performance of the photoelectric pyrometer detection optical system and the accuracy of temperature measurement of the photoelectric pyrometer are improved by optimization design of the detection optical system.展开更多
To improve the detection accuracy and robustness of crowd anomaly detection,especially crowd emergency evacuation detection,the abnormal crowd behavior detection method is proposed.This method is based on the improved...To improve the detection accuracy and robustness of crowd anomaly detection,especially crowd emergency evacuation detection,the abnormal crowd behavior detection method is proposed.This method is based on the improved statistical global optical flow entropy which can better describe the degree of chaos of crowd.First,the optical flow field is extracted from the video sequences and a 2D optical flow histogram is gained.Then,the improved optical flow entropy,combining information theory with statistical physics is calculated from 2D optical flow histograms.Finally,the anomaly can be detected according to the abnormality judgment formula.The experimental results show that the detection accuracy achieved over 95%in three public video datasets,which indicates that the proposed algorithm outperforms other state-of-the-art algorithms.展开更多
Wheat quality detection is essential to ensure the safety ofwheat circulation and storage.The traditional wheat quality detection methods mainly include artificial sensory evaluation and physicochemical index analysis...Wheat quality detection is essential to ensure the safety ofwheat circulation and storage.The traditional wheat quality detection methods mainly include artificial sensory evaluation and physicochemical index analysis,which are difficult to meet the requirements for high accuracy and efficiency in modern wheat quality detection due to the disadvantages of subjectivity,destruction of sample integrity and low efficiency.With the rapid development of optical technology,various optical-based methods,using near-infrared spectroscopy technology,hyperspectral imaging technology and terahertz,etc.,have been proposed for wheat quality detection.These methods have the characteristics of nondestructiveness and high efficiency which make them popular in wheat quality detection in recent years.In this paper,various state-of-the-art optical-based techniques of wheat quality detection are analyzed and summarized in detail.Firstly,the principle and process of common optical non-destructive detection methods for wheat quality are introduced.Then,the optical techniques used in these detection methods are divided into seven categories,and the comparison of these technologies and their advantages and disadvantages are further discussed.It shows that terahertz technology is regarded as the most promising wheat quality detection method compared with other optical detection technologies,because it can not only detect most types of wheat deterioration,but also has higher accuracy and efficiency.Finally,the research of optical technology in wheat quality detection is prospected.The future research of optical technology-based wheat quality detection mainly includes the construction of wheat quality optical detection standardization database,the fusion of multiple optical detection technologies and multiple quality index information,the improvement of the anti-interference of optical technology and the industrialization of optical inspection technology for wheat quality.These studies are of great significance to improve the detection technology of wheat and ensure the storage safety of wheat in the future.展开更多
Co-phasing between different sub-apertures is important for sparse optical synthetic aperture telescope systems to achieve high-resolution imaging. For co-phasing detection in such a system, a new aspect of the system...Co-phasing between different sub-apertures is important for sparse optical synthetic aperture telescope systems to achieve high-resolution imaging. For co-phasing detection in such a system, a new aspect of the system＇s far-field interferometry is analysed and used to construct a novel method to detect piston errors. An optical setup is built to demonstrate the efficacy of this method. Experimental results show that the relative differences between measurements by this method and the criterion are less than 4%, and their residual detecting errors are about 0.01 A for different piston errors, which makes the use of co-phasing detection within such a system promising.展开更多
We demonstrated a new method of atom detection by means of the magnetic optical effect. The number density of the atom cloud was measured by detecting the rotation angle of the polarization plane of linearly polarized...We demonstrated a new method of atom detection by means of the magnetic optical effect. The number density of the atom cloud was measured by detecting the rotation angle of the polarization plane of linearly polarized probe light when propagating inside the atomic cloud. Detuning, the magnetic field and light intensity dependencies of the rotation angle were studied theoretically and experimentally to find the best parameter for atom detection. In this way, we managed to achieve a rotation angle of 0.22 rad with a signal to noise ratio （SNR） of 75 and a contrast of 87.5%.展开更多
Picosecond optical parametric generation and amplification in the near-infrared region within 1.361-1.656 μm and the mid-infrared region within 2.976-4.875 μm is constructed on the basis of bulk MgO：LiNbO 3 crystal...Picosecond optical parametric generation and amplification in the near-infrared region within 1.361-1.656 μm and the mid-infrared region within 2.976-4.875 μm is constructed on the basis of bulk MgO：LiNbO 3 crystals pumped at 1.064 μm.The maximum pulse energy reaches 1.3 mJ at 1.464 μm and 0.47 mJ at 3.894 μm,corresponding to a pumpto-idler photon conversion efficiency of 25%.By seeding the hard-to-measure mid-infrared radiation as the idler in the optical parametric amplification and measuring the amplified and frequency up-converted signal in the near-infrared or even visible region,one can measure very week mid-infrared radiation with ordinary detectors,which are insensitive to mid-infrared radiation,with a very high gain.A maximum gain factor of about 7 脳 10 7 is achieved at the mid-infrared wavelength of 3.374 μm and the corresponding energy detection limit is as low as about 390 aJ per pulse.展开更多
Deep learning(DL)is one of the fastest developing areas in artificial intelligence,it has been recently gained studies and application in computer vision,automatic driving,automatic speech recognition,and communicatio...Deep learning(DL)is one of the fastest developing areas in artificial intelligence,it has been recently gained studies and application in computer vision,automatic driving,automatic speech recognition,and communication.This paper uses the DL method to design a symbol detection algorithm in receiver for optical communication systems.The proposed DL based method is implemented by a non-causal temporal convolutional network(ncTCN),which is a convolutional neural network and appropriate for sequence processing.Meanwhile,we adopt three methods to realize the training process for multiple signal-to-noise ratios of the AWGN channel.Furthermore,we apply two nonlinear activation functions for the noise robustness to the proposed ncTCN.Without losing generality,we apply the ncTCN-based receiver to the 16-ary quadrature amplitude modulation optical communication system in the simulation experiment.According to the experiment results,the proposed method can obtain some bit error rate performance gain compared to some conventional receivers.展开更多
Friction plays a critical role in dexterous robotic manipulation.However,realizing friction sensing remains a challenge due to the difficulty in designing sensing structures to decouple multi-axial forces.Inspired by ...Friction plays a critical role in dexterous robotic manipulation.However,realizing friction sensing remains a challenge due to the difficulty in designing sensing structures to decouple multi-axial forces.Inspired by the topological mechanics of knots,we construct optical fiber knot(OFN)sensors for slip detection and friction measurement.By introducing localized self-contacts along the fiber,the knot structure enables anisotropic responses to normal and frictional forces.By employing OFNs and a change point detection algorithm,we demonstrate adaptive robotic grasping of slipping cups.We further develop a robotic finger that can measure tri-axial forces via a centrosymmetric architecture composed of five OFNs.Such a tactile finger allows a robotic hand to manipulate human tools dexterously.This work could provide a straightforward and cost-effective strategy for promoting adaptive grasping,dexterous manipulation,and human-robot interaction with tactile sensing.展开更多
Development of a prototype of a portable optical sensing system is presented for fast detecting of samples’fluorescence spectra.A compact configuration is achieved by integrating a small spectrometer,a microcontrolle...Development of a prototype of a portable optical sensing system is presented for fast detecting of samples’fluorescence spectra.A compact configuration is achieved by integrating a small spectrometer,a microcontroller,a Universal Serial Bus(USB)Host Shield,a network module,and a web server.The fluorescence spectra of a tested sample can be obtained.Then the test data are sent through network communication to our Cloud Server which can store the data for further analyses.With this configuration,test results can be revealed in a short time and downloaded by users to their laptops,tablets or cellphones anytime and anywhere.展开更多
The specific detection of tumor markers is crucial in early tumor screening and subsequent treatment processes.To ac-curately distinguish the signal response caused by trace markers,the high demodulation resolution of...The specific detection of tumor markers is crucial in early tumor screening and subsequent treatment processes.To ac-curately distinguish the signal response caused by trace markers,the high demodulation resolution of the sensor is necessary.In this paper,we propose a dual-wavelength fiber laser sensing system enhanced with microwave photonics de-modulation technology to achieve high-resolution tumor marker detection.This sensing system can simultaneously perform spectral wavelength-domain and frequency-domain analyses.Experimental results demonstrate that this system's refractive index(RI)sensitivity reaches 1083 nm/RIU by wavelength analysis and-1902 GHz/RIU by frequency analysis,with ideal detection resolutions of 1.85×10^(-5)RIU and 5.26×10^(-8)RIU,respectively.Compared with traditional wavelength domain analysis,the demodulation resolution is improved by three orders of magnitude,based on the same sensing structure.To validate its biosensing performance,carcinoembryonic antigen-related cell adhesion molecule 5(CEACAM5)is selected as the detection target.Experimental results show that the improved sensing system has a limit of detection(LOD)of 0.076 ng/mL and a detection resolution of 0.008 ng/mL.Experimental results obtained from human serum samples are consistent with clinical data,highlighting the strong clinical application potential of the proposed sens-ing system and analysis method.展开更多
We carried out a proof-of-principle demonstration of the reconstruction of a static vector magnetic field involving adjacent three nitrogen-vacancy(NV) sensors with corresponding different NV symmetry axes in a bulk d...We carried out a proof-of-principle demonstration of the reconstruction of a static vector magnetic field involving adjacent three nitrogen-vacancy(NV) sensors with corresponding different NV symmetry axes in a bulk diamond. By means of optical detection of the magnetic resonance(ODMR) techniques, our experiment employs the continuous wave(CW) to monitor resonance frequencies and it extracts the information of the detected field strength and polar angles with respect to each NV frame of reference. Finally, the detected magnetic field relative to a fixed laboratory reference frame was reconstructed from the information acquired by the multi-NV sensor.展开更多
Grazing incidence optics （GIO） is the most important compound in an x-ray detection system; it is used to concentrate the x-ray photons from outer space. A nested planar GIO for x-ray concentration is designed and d...Grazing incidence optics （GIO） is the most important compound in an x-ray detection system; it is used to concentrate the x-ray photons from outer space. A nested planar GIO for x-ray concentration is designed and developed by authors in this paper; planar segments are used as the reflection mirror instead of curved segments because of the simple process and low cost. After the complex assembling process with a special metal supporter, a final circle light spot of φ 12 mm was obtained in the visible light testing experiment of GIO; the effective area of 1710.51 mm^2@ 1 keV and 530 mm^2@8 keV is obtained in the x-ray testing experiment with the GIO-SDD combination, which is supposed to be a concentrating detector in xray detection systems.展开更多
In optical performance monitoring system,the analog to digital converter is needed to detect the peak of nanosecond pulse and get the signal envelope.A scheme based on a designed anti-aliasing filter and analog to dig...In optical performance monitoring system,the analog to digital converter is needed to detect the peak of nanosecond pulse and get the signal envelope.A scheme based on a designed anti-aliasing filter and analog to digital converter is proposed to broaden the nanosecond pulse and make it easier for the analog to digital converter to catch the peak of the nanosecond pulse.The experimental results demonstrate that,with the proposed scheme,the optical performance system needs less time to get the recovered eye-diagram of high speed optical data signal,and is robust to phase mismatch in the analog to digital converter circuit.展开更多
On the basis of Hartmann Shack sensor imaging analysis, a new method is presented with which the wavefront slope can be obtained when the object is incoherent and extended. This method, which is demonstrated by both ...On the basis of Hartmann Shack sensor imaging analysis, a new method is presented with which the wavefront slope can be obtained when the object is incoherent and extended. This method, which is demonstrated by both theoretical interpreting and computer simulation, explains how to measure the wavefront slope difference between two sub apertures through the determination of image displacements on detector plane. It includes a fast and accurate digital algorithm for detecting wavefront disturbance, which is much suitable for realization in such electrical hardwares as digital signal processors.展开更多
Frequency up-conversion is an effective method of mid-infrared(MIR) detection by converting long-wavelength photons to the visible domain, where efficient detectors are readily available. Here, we generate MIR light c...Frequency up-conversion is an effective method of mid-infrared(MIR) detection by converting long-wavelength photons to the visible domain, where efficient detectors are readily available. Here, we generate MIR light carrying orbital angular momentum(OAM) from a difference frequency generation process and perform up-conversion on it via sum frequency conversion in a bulk quasi-phase-matching crystal. The maximum quantum conversion efficiencies from MIR to visible are 34.0%, 10.4%, and 3.5% for light with topological charges of 0, 1, and 2, respectively, achieved by utilizing an optimized strong pump light. We also verify the OAM conservation with a specially designed interferometer, and the results agree well with the numerical simulations. Our study opens up the possibilities for generating, manipulating, and detecting MIR light that carries OAM, and will have great potential for optical communications and remote sensing in the MIR regime.展开更多
Phase is one of the most important parameters of electromagnetic waves. It is the phase distribution that determines the propagation, reflection, refraction, focusing, divergence, and coupling features of light, and f...Phase is one of the most important parameters of electromagnetic waves. It is the phase distribution that determines the propagation, reflection, refraction, focusing, divergence, and coupling features of light, and further affects the intensity distribution. In recent years, the designs of surface plasmon polariton （SPP） devices have mostly been based on the phase modulation and manipulation. Here we demonstrate a phase sensitive multi-parameter heterodyne scanning near-field opti- cal microscope （SNOM） with an aperture probe in the visible range, with which the near field optical phase and amplitude distributions can be simultaneously obtained. A novel architecture combining a spatial optical path and a fiber optical path is employed for stability and flexibility. Two kinds of typical nano-photonic devices are tested with the system. With the phase-sensitive SNOM, the phase and amplitude distributions of any nano-optical field and localized field generated with any SPP nano-structures and irregular phase modulation surfaces can be investigated. The phase distribution and the interference pattern will help us to gain a better understanding of how light interacts with SPP structures and how SPP waves generate, localize, convert, and propagate on an SPP surface. This will be a significant guidance on SPP nano-structure design and optimization.展开更多
基金Supported by the Natural Science Foundation of Jiangsu Province (BK2009371)the National High Technology Research and Development Program of China ("863" Program) (2008AA02Z438)~~
文摘The effective detection depth of the needle-like optical probe is studied. The light transport model in highly scattering tissue is the diffusion equation and the boundary is Neuman. The sensitivity matrix is related to the position of the light source and the detector. It can be used to evaluate the effective detection depth. The sensitivity matrix is defined as the multiplication of the source and detector hght distribution. Six different groups about ix parameters including the source diameter and detector fibers, the core-to-core distance between the source and detector fibers, the opotode depth, the absorption, and reduced scattering coefficient, are used as experimental models. The relationship between the six parameters and the effective detection depth is analyzed. Resuits can be used to study the spatial resolution and the depth of multi-fibers.
基金Project supported by the National Natural Science Foundation of China (Grant No.12274045)。
文摘Infrared signal detection is widely used in many fields.Due to the detection principle,however,the accuracy and range of detection are limited.Thanks to the ultra stability of the^(87)Sr optical lattice clock,external infrared electromagnetic wave disturbances can be responded to.Utilizing the ac Stark shift of the clock transition,we propose a new method to detect infrared signals.According to our calculations,the theoretical detection accuracy in the vicinity of its resonance band of 2.6μm can reach the order of 10-14W,while the minimum detectable signal of common detectors is on the order of 10^(-10)W.
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.
文摘The optical wireless communication (OWC) is afading channel because of the effect of atmosphericattenuation. We introduce a cumulant-based adaptive detection technique to providehigh performance for OWC. The received signalof OWC over strong turbulence channels is assumedto be a mixture of K-distributed fading andGaussian distributed thermal noise. In order tomitigate the fading induced by turbulence, thedecision threshold-updating algorithm based onsecond and higher order cumulants is proposed,which is able to operate in an unknown turbulenceenvironment. The performance of the adaptiveprocessing scheme has been evaluated by meansof Monte Carlo simulations. It is shown that theproposed approach proves valuable for a limitednumber K of memory data.
基金Jilin Province Science and Technology Development Plan Project(20190701024GH)。
文摘The measurement and control of high temperature play very important roles in national defense,military,scientific experiments,industrial and agricultural production.Photoelectric pyrometer is one of the important radiation thermometers for non-contact temperature measurement.It has an important application in the field of high temperature measurement,and its performance directly affects the accuracy of temperature measurement.By improving the design of the detection optical system of the photoelectric pyrometer,the imaging performance of the photoelectric pyrometer can be improved effectively,and the temperature measurement accuracy can be improved.In this paper,the temperature measurement principle of photoelectric pyrometer,the wo rking principle of the detection optical system and the composition of the system are introduced.The optical components that affect the imaging of the optical system of the photoelectric pyrometer are analyzed.The optical pyrometer detection optical system is simulated by ZEMAX software,based on the analysis results,the Modulation Transfer Function(MTF)and the spot Diagram are used as the main evaluation criteria to optimize the design of the objective lens of the photoelectric pyrometer detection optical system.The imaging performance of the photoelectric pyrometer detection optical system and the accuracy of temperature measurement of the photoelectric pyrometer are improved by optimization design of the detection optical system.
基金National Natural Science Foundation of China(61701029)。
文摘To improve the detection accuracy and robustness of crowd anomaly detection,especially crowd emergency evacuation detection,the abnormal crowd behavior detection method is proposed.This method is based on the improved statistical global optical flow entropy which can better describe the degree of chaos of crowd.First,the optical flow field is extracted from the video sequences and a 2D optical flow histogram is gained.Then,the improved optical flow entropy,combining information theory with statistical physics is calculated from 2D optical flow histograms.Finally,the anomaly can be detected according to the abnormality judgment formula.The experimental results show that the detection accuracy achieved over 95%in three public video datasets,which indicates that the proposed algorithm outperforms other state-of-the-art algorithms.
基金supported by the scientific and technological key project in Henan Province (No.212102210148)Open fund of Key Laboratory of Grain Information Processing and Control (No.KFJJ-2018-101)
文摘Wheat quality detection is essential to ensure the safety ofwheat circulation and storage.The traditional wheat quality detection methods mainly include artificial sensory evaluation and physicochemical index analysis,which are difficult to meet the requirements for high accuracy and efficiency in modern wheat quality detection due to the disadvantages of subjectivity,destruction of sample integrity and low efficiency.With the rapid development of optical technology,various optical-based methods,using near-infrared spectroscopy technology,hyperspectral imaging technology and terahertz,etc.,have been proposed for wheat quality detection.These methods have the characteristics of nondestructiveness and high efficiency which make them popular in wheat quality detection in recent years.In this paper,various state-of-the-art optical-based techniques of wheat quality detection are analyzed and summarized in detail.Firstly,the principle and process of common optical non-destructive detection methods for wheat quality are introduced.Then,the optical techniques used in these detection methods are divided into seven categories,and the comparison of these technologies and their advantages and disadvantages are further discussed.It shows that terahertz technology is regarded as the most promising wheat quality detection method compared with other optical detection technologies,because it can not only detect most types of wheat deterioration,but also has higher accuracy and efficiency.Finally,the research of optical technology in wheat quality detection is prospected.The future research of optical technology-based wheat quality detection mainly includes the construction of wheat quality optical detection standardization database,the fusion of multiple optical detection technologies and multiple quality index information,the improvement of the anti-interference of optical technology and the industrialization of optical inspection technology for wheat quality.These studies are of great significance to improve the detection technology of wheat and ensure the storage safety of wheat in the future.
基金Project supported by the Young Scientists Fund of the National Natural Science Foundation of China (Grant No. 61008038)
文摘Co-phasing between different sub-apertures is important for sparse optical synthetic aperture telescope systems to achieve high-resolution imaging. For co-phasing detection in such a system, a new aspect of the system＇s far-field interferometry is analysed and used to construct a novel method to detect piston errors. An optical setup is built to demonstrate the efficacy of this method. Experimental results show that the relative differences between measurements by this method and the criterion are less than 4%, and their residual detecting errors are about 0.01 A for different piston errors, which makes the use of co-phasing detection within such a system promising.
基金Project supported by the National Basic Research Program of China (Grant No. 2011CB921504)the National Natural Science Foundation of China (Grant No. 10974210)
文摘We demonstrated a new method of atom detection by means of the magnetic optical effect. The number density of the atom cloud was measured by detecting the rotation angle of the polarization plane of linearly polarized probe light when propagating inside the atomic cloud. Detuning, the magnetic field and light intensity dependencies of the rotation angle were studied theoretically and experimentally to find the best parameter for atom detection. In this way, we managed to achieve a rotation angle of 0.22 rad with a signal to noise ratio （SNR） of 75 and a contrast of 87.5%.
基金Project supported by the National Natural Science Foundation of China (Grant No. 61078005)the National Basic ResearchProgram of China (Grant No. 2007CB613205)the China Postdoctoral Science Foundation
文摘Picosecond optical parametric generation and amplification in the near-infrared region within 1.361-1.656 μm and the mid-infrared region within 2.976-4.875 μm is constructed on the basis of bulk MgO：LiNbO 3 crystals pumped at 1.064 μm.The maximum pulse energy reaches 1.3 mJ at 1.464 μm and 0.47 mJ at 3.894 μm,corresponding to a pumpto-idler photon conversion efficiency of 25%.By seeding the hard-to-measure mid-infrared radiation as the idler in the optical parametric amplification and measuring the amplified and frequency up-converted signal in the near-infrared or even visible region,one can measure very week mid-infrared radiation with ordinary detectors,which are insensitive to mid-infrared radiation,with a very high gain.A maximum gain factor of about 7 脳 10 7 is achieved at the mid-infrared wavelength of 3.374 μm and the corresponding energy detection limit is as low as about 390 aJ per pulse.
基金supported by National Key Research and Development Plan(2018YFB1801500)Manned Space Pre-research Project(N0.060501)。
文摘Deep learning(DL)is one of the fastest developing areas in artificial intelligence,it has been recently gained studies and application in computer vision,automatic driving,automatic speech recognition,and communication.This paper uses the DL method to design a symbol detection algorithm in receiver for optical communication systems.The proposed DL based method is implemented by a non-causal temporal convolutional network(ncTCN),which is a convolutional neural network and appropriate for sequence processing.Meanwhile,we adopt three methods to realize the training process for multiple signal-to-noise ratios of the AWGN channel.Furthermore,we apply two nonlinear activation functions for the noise robustness to the proposed ncTCN.Without losing generality,we apply the ncTCN-based receiver to the 16-ary quadrature amplitude modulation optical communication system in the simulation experiment.According to the experiment results,the proposed method can obtain some bit error rate performance gain compared to some conventional receivers.
基金grateful for financial supports from National Natural Science Foundation of China(61975173)China Postdoctoral Science Foundation(2022M722907,2022M722909)+2 种基金Zhejiang Provincial Natural Science Foundation of China(LQ23F010015)Key Research and Development Project of Zhejiang Province(2021C05003)Major Scientific Research Project of Zhejiang Lab(2019MC0AD01).
文摘Friction plays a critical role in dexterous robotic manipulation.However,realizing friction sensing remains a challenge due to the difficulty in designing sensing structures to decouple multi-axial forces.Inspired by the topological mechanics of knots,we construct optical fiber knot(OFN)sensors for slip detection and friction measurement.By introducing localized self-contacts along the fiber,the knot structure enables anisotropic responses to normal and frictional forces.By employing OFNs and a change point detection algorithm,we demonstrate adaptive robotic grasping of slipping cups.We further develop a robotic finger that can measure tri-axial forces via a centrosymmetric architecture composed of five OFNs.Such a tactile finger allows a robotic hand to manipulate human tools dexterously.This work could provide a straightforward and cost-effective strategy for promoting adaptive grasping,dexterous manipulation,and human-robot interaction with tactile sensing.
基金supported by the National Key Development Program (2016YFB1102704)Natural Science Foundation of Liaoning Province (2015020115)+1 种基金National Natural Science Foundation of China (U1609209)National Science Fund for Distinguished Youth Scholars (51625504)
文摘Development of a prototype of a portable optical sensing system is presented for fast detecting of samples’fluorescence spectra.A compact configuration is achieved by integrating a small spectrometer,a microcontroller,a Universal Serial Bus(USB)Host Shield,a network module,and a web server.The fluorescence spectra of a tested sample can be obtained.Then the test data are sent through network communication to our Cloud Server which can store the data for further analyses.With this configuration,test results can be revealed in a short time and downloaded by users to their laptops,tablets or cellphones anytime and anywhere.
基金supported in part by the Science and Technology Department of Guangdong Province(2021A0505080002)Department of Natural Resources of Guangdong Province(GDNRC[2022]No.22)+2 种基金Science,Technology and Innovation Commission of Shenzhen Municipality(20220815121807001)Hunan Provincial Natural Science Foundation of China(under Grant Nos.2023JJ30209)Hunan Provincial Education Department Science Research Fund of China(under Grant Nos.22B0862).
文摘The specific detection of tumor markers is crucial in early tumor screening and subsequent treatment processes.To ac-curately distinguish the signal response caused by trace markers,the high demodulation resolution of the sensor is necessary.In this paper,we propose a dual-wavelength fiber laser sensing system enhanced with microwave photonics de-modulation technology to achieve high-resolution tumor marker detection.This sensing system can simultaneously perform spectral wavelength-domain and frequency-domain analyses.Experimental results demonstrate that this system's refractive index(RI)sensitivity reaches 1083 nm/RIU by wavelength analysis and-1902 GHz/RIU by frequency analysis,with ideal detection resolutions of 1.85×10^(-5)RIU and 5.26×10^(-8)RIU,respectively.Compared with traditional wavelength domain analysis,the demodulation resolution is improved by three orders of magnitude,based on the same sensing structure.To validate its biosensing performance,carcinoembryonic antigen-related cell adhesion molecule 5(CEACAM5)is selected as the detection target.Experimental results show that the improved sensing system has a limit of detection(LOD)of 0.076 ng/mL and a detection resolution of 0.008 ng/mL.Experimental results obtained from human serum samples are consistent with clinical data,highlighting the strong clinical application potential of the proposed sens-ing system and analysis method.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11305074,11135002,11804112,and 11275083)the Key Program of the Education Department Outstanding Youth Foundation of Anhui Province,China(Grant No.gxyqZD2017080)+2 种基金the Natural Science Foundation of Anhui Province,China(Grant No.KJHS2015B09)the Open Fund of Anhui Ley Laboratory for Condensed Matter Physics under Extreme Conditions and CAS Key Laboratory of Microscale Magnetic Resonance(Grant No.KLMMR201804)the Fund of Scientific Research Platform of Huangshan University
文摘We carried out a proof-of-principle demonstration of the reconstruction of a static vector magnetic field involving adjacent three nitrogen-vacancy(NV) sensors with corresponding different NV symmetry axes in a bulk diamond. By means of optical detection of the magnetic resonance(ODMR) techniques, our experiment employs the continuous wave(CW) to monitor resonance frequencies and it extracts the information of the detected field strength and polar angles with respect to each NV frame of reference. Finally, the detected magnetic field relative to a fixed laboratory reference frame was reconstructed from the information acquired by the multi-NV sensor.
基金supported by the National Natural Science Foundation of China(Grant No.61471357)the State Key Laboratory of Geo-Information Engineering Foundation(Grant No.SKLGIE2014-M-2-1)
文摘Grazing incidence optics （GIO） is the most important compound in an x-ray detection system; it is used to concentrate the x-ray photons from outer space. A nested planar GIO for x-ray concentration is designed and developed by authors in this paper; planar segments are used as the reflection mirror instead of curved segments because of the simple process and low cost. After the complex assembling process with a special metal supporter, a final circle light spot of φ 12 mm was obtained in the visible light testing experiment of GIO; the effective area of 1710.51 mm^2@ 1 keV and 530 mm^2@8 keV is obtained in the x-ray testing experiment with the GIO-SDD combination, which is supposed to be a concentrating detector in xray detection systems.
基金supported by National 863 Program of China(2013AA013401),P.R.ChinaNational Natural Science Foundation of China under Grant No.61177067,No.61027007,and No.61331010
文摘In optical performance monitoring system,the analog to digital converter is needed to detect the peak of nanosecond pulse and get the signal envelope.A scheme based on a designed anti-aliasing filter and analog to digital converter is proposed to broaden the nanosecond pulse and make it easier for the analog to digital converter to catch the peak of the nanosecond pulse.The experimental results demonstrate that,with the proposed scheme,the optical performance system needs less time to get the recovered eye-diagram of high speed optical data signal,and is robust to phase mismatch in the analog to digital converter circuit.
文摘On the basis of Hartmann Shack sensor imaging analysis, a new method is presented with which the wavefront slope can be obtained when the object is incoherent and extended. This method, which is demonstrated by both theoretical interpreting and computer simulation, explains how to measure the wavefront slope difference between two sub apertures through the determination of image displacements on detector plane. It includes a fast and accurate digital algorithm for detecting wavefront disturbance, which is much suitable for realization in such electrical hardwares as digital signal processors.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 92065101 and 11934013)Anhui Initiative In Quantum Information Technologies (Grant No. AHY020200)。
文摘Frequency up-conversion is an effective method of mid-infrared(MIR) detection by converting long-wavelength photons to the visible domain, where efficient detectors are readily available. Here, we generate MIR light carrying orbital angular momentum(OAM) from a difference frequency generation process and perform up-conversion on it via sum frequency conversion in a bulk quasi-phase-matching crystal. The maximum quantum conversion efficiencies from MIR to visible are 34.0%, 10.4%, and 3.5% for light with topological charges of 0, 1, and 2, respectively, achieved by utilizing an optimized strong pump light. We also verify the OAM conservation with a specially designed interferometer, and the results agree well with the numerical simulations. Our study opens up the possibilities for generating, manipulating, and detecting MIR light that carries OAM, and will have great potential for optical communications and remote sensing in the MIR regime.
基金supported by the National Natural Science Foundation of China(Grant Nos.61177089,61227014,and 60978047)
文摘Phase is one of the most important parameters of electromagnetic waves. It is the phase distribution that determines the propagation, reflection, refraction, focusing, divergence, and coupling features of light, and further affects the intensity distribution. In recent years, the designs of surface plasmon polariton （SPP） devices have mostly been based on the phase modulation and manipulation. Here we demonstrate a phase sensitive multi-parameter heterodyne scanning near-field opti- cal microscope （SNOM） with an aperture probe in the visible range, with which the near field optical phase and amplitude distributions can be simultaneously obtained. A novel architecture combining a spatial optical path and a fiber optical path is employed for stability and flexibility. Two kinds of typical nano-photonic devices are tested with the system. With the phase-sensitive SNOM, the phase and amplitude distributions of any nano-optical field and localized field generated with any SPP nano-structures and irregular phase modulation surfaces can be investigated. The phase distribution and the interference pattern will help us to gain a better understanding of how light interacts with SPP structures and how SPP waves generate, localize, convert, and propagate on an SPP surface. This will be a significant guidance on SPP nano-structure design and optimization.
