The interfacial debonding in fiber-reinforced plastic(FRP)strengthened repair material will affect the bonding strength and lead to failure of the repair without warning.Unfortunately the interfacial damage is normall...The interfacial debonding in fiber-reinforced plastic(FRP)strengthened repair material will affect the bonding strength and lead to failure of the repair without warning.Unfortunately the interfacial damage is normally invisible and often in the form of a patch rather than a through-width crack.Therefore,a debonding patch detection technique based on fiber optic interferometry is proposed.A quasi-impulse loading is applied with a rubberhead hammer and the total elongation of a surface-mounted optical fiber along the length of the repair material is measured as a function of load position.When a debonding patch is present,the induced sudden slope or sign change on the plot of fiber integral strain v.s.load position will reveal the extent and the location of the debonded area.The results of the study indicate that the proposed technique is applicable for debonding patch detection in repaired members under various support conditions.展开更多
Fiber-optic sensing technology has the advantages of passivity, anti-electromagnetic interference, longdistancemeasurement, high sensitivity and high accuracy, small size, and adaptability to harsh environments such a...Fiber-optic sensing technology has the advantages of passivity, anti-electromagnetic interference, longdistancemeasurement, high sensitivity and high accuracy, small size, and adaptability to harsh environments such ashigh-vacuum, high-pressure, and strong magnetic fields compared with the traditional electrical sensing technology.However, with the increasing application requirements, how to further improve the sensitivity of fiber-optic sensors,extend the detection limit and improve the maintenance-free capability has become one of the core issues of thecurrent research. This paper reviews the principle, preparation, and application of fiber-optic microstructured sensingbased on abrupt field type. It specifically outlines the development and applications of micro-nano optical fibers,photonic crystal optical fibers, optical fiber gratings and structured optical fibers, and lists the main preparationmethods of two types of micro-nano optical fibers from the basic theory of optical fiber microstructured sensordevices.展开更多
Laser-driven inertial confinement fusion(ICF)is an important experimental platform for high-energy-density physics research under extreme conditions.In ICF research,high-quality shock waves are key to fusion energy re...Laser-driven inertial confinement fusion(ICF)is an important experimental platform for high-energy-density physics research under extreme conditions.In ICF research,high-quality shock waves are key to fusion energy release.The velocity interferometer system for any reflector(VISAR)is the most important diagnostic technique for measuring quantities such as shock wave and particle velocities with high precision and high spatiotemporal resolution.This paper provides a detailed introduction to the various configurations of VISAR on 10 and 100 kJ-level laser facilities in China,including Line VISAR,Dual-Axis VISAR,Wide-Angle VISAR,and Compressed Ultrafast Photography-VISAR.Recent advances and applications of VISAR diagnostics at these laser facilities are presented,and the future trend of development of high-spatiotemporal-resolution velocity diagnostic technology is described.展开更多
Ultrasound neuromodulation offers a non-invasive approach to modulate neural activity in the central nervous system.Precise,minimally invasive devices capable of targeted stimulation remain limited.A 200μm diameter f...Ultrasound neuromodulation offers a non-invasive approach to modulate neural activity in the central nervous system.Precise,minimally invasive devices capable of targeted stimulation remain limited.A 200μm diameter fiber-optic photoacoustic emitter(FPE)was developed,coated with a MXene(Ti3C2Tx)and polydimethylsiloxane composite to generate controllable,broadband ultrasonic waves with high spatial precision.Using this FPE to stimulate the medial prefrontal cortex in mice,it was observed marked alleviation of acute social defeat stress-induced emotional stress,evidenced by reduced anxiety-like behavior and increased social interaction.This approach enables near-field,broadband,and tunable ultrasound neuromodulation with potential applications in treating neuropsychiatric disorders involving emotional regulation.展开更多
We theoretically investigate the phase sensitivity of a truncated SU(1,1)interferometer fed with a two-mode coherent state and employing double-port homodyne detection.On the one hand,we analytically demonstrate that ...We theoretically investigate the phase sensitivity of a truncated SU(1,1)interferometer fed with a two-mode coherent state and employing double-port homodyne detection.On the one hand,we analytically demonstrate that the two-mode coherent state provides better phase sensitivity than the single-mode coherent state.In addition,we show that the doubleport homodyne detection is a quasi-optimal measurement.For a bright coherent-state input,the sensitivity of this scheme saturates the phase-sensitivity bound determined by the quantum Fisher information.On the other hand,we quantitatively illustrate the advantage of double-port homodyne detection over the single-port scheme under ideal conditions and in the presence of photon loss,respectively.Furthermore,our analysis indicates that the scheme we propose is robust against photon loss.展开更多
Rotating Single-Baseline Interferometer(RSBI)systems have attracted considerable attention for Direct Position Determination(DPD)due to their simplicity and high localization accuracy.Nevertheless,the growing complexi...Rotating Single-Baseline Interferometer(RSBI)systems have attracted considerable attention for Direct Position Determination(DPD)due to their simplicity and high localization accuracy.Nevertheless,the growing complexity of electromagnetic environments has led to scenarios with multiple time-frequency aliased sources,rendering conventional DPD methods for RSBI systems ineffective.Previous studies have predominantly concentrated on deploying antenna arrays and applying related signal-processing techniques for localization.Typically,these approaches necessitate that the number of physical antennas exceeds the number of sources.For RSBI systems already in practical operation,this would entail the installation of additional physical antennas,which implies equipment recycling and hardware upgrades.In numerous cases,such modifications are unfeasible.This paper proposes a novel Relative Offset-based Direct Position Determination(RO-DPD)method for RSBI systems that can handle multiple time-frequency aliased sources.The proposed method overcomes the challenge of simultaneous positioning without requiring hardware modifications by leveraging time accumulation and algorithmic enhancements.The implementation of the method involves three key steps.Firstly,the rotation of the interferometer is synthesized into a virtual Uniform Circular Array(UCA).Secondly,a novel estimation variable,termed relative offset,is introduced.The variable serves as an intermediate parameter to establish correlation equations between the positions of multiple time-frequency aliased sources and the intercepted signals.Thirdly,the relative offset model in the UCA is transformed into a virtual Uniform Linear Array(ULA)model,from which the cost function can be derived via the Spatial Smoothing(SS)MUSIC algorithm.Theoretical analysis and simulation results verify the effectiveness of the proposed method.Compared with traditional approaches,the RO-DPD method maintains the low complexity of RSBI systems while demonstrating robust performance in complex electromagnetic environments.展开更多
Tilt-to-length(TTL)coupling noise is a critical issue in space-based gravitational wave detection due to its complex dependence on multiple interacting factors,which complicates the identification of dominant paramete...Tilt-to-length(TTL)coupling noise is a critical issue in space-based gravitational wave detection due to its complex dependence on multiple interacting factors,which complicates the identification of dominant parameters.To address this challenge,we develop a simulation model of the Taiji scientific interferometer,generating noise datasets under multiparameter conditions.Given the uniqueness of the telescope as well as the convergence behavior of the algorithm,the analysis is structured hierarchically:(i)the telescope level and(ii)the optical bench level.A hierarchical framework combining XGBoost and SHapley Additive exPlanations(SHAP)values is employed to model the intricate relationships between parameters and TTL coupling noise,supplemented by sensitivity analysis.Our results identify pointing jitter and telescope radius as the dominant parameters at the telescope level,while the angles of the plane mirrors and beam splitters are most influential at the optical bench level.The parameter space is reduced from 86 dimensions to 14 dimensions without sacrificing model accuracy.This approach offers actionable insights for optimizing the Taiji interferometer design.展开更多
An ultrasonic sensitivity-improved fiber-optic Fabry-Perot interferometer （FPI） is proposed and employed for ultra- sonic imaging of seismic physical models （SPMs）. The FPI comprises a flexible ultra-thin gold fil...An ultrasonic sensitivity-improved fiber-optic Fabry-Perot interferometer （FPI） is proposed and employed for ultra- sonic imaging of seismic physical models （SPMs）. The FPI comprises a flexible ultra-thin gold film and the end face of a graded-index multimode fiber （MMF）, both of which are enclosed in a ceramic tube. The MMF in a specified length can collimate the diverged light beam and compensate for the light loss inside the air cavity, leading to an increased spectral fringe visibility and thus a steeper spectral slope. By using the spectral sideband filtering technique, the collimated FP1 shows an improved ultrasonic response. Moreover, two-dimensional images of two SPMs are achieved in air by recon- structing the pulse-echo signals through using the time-of-flight approach. The proposed sensor with easy fabrication and compact size can be a good candidate for high-sensitivity and high-precision nondestructive testing of SPMs.展开更多
In order to improve the multiplexing capability of the optical sensors based on the lower interferential optic fiber sensing technology and the white light fiber-optic Mach-Zehnder interferometer,reflective ladder top...In order to improve the multiplexing capability of the optical sensors based on the lower interferential optic fiber sensing technology and the white light fiber-optic Mach-Zehnder interferometer,reflective ladder topology network ( RLT) with tailored formula was proposed. The topology network consists of 6 rungs sensing elements linked by 5 couplers. Two cases with different choices of couplers were contrasted: one is equal coupling ratio,and the other is tailored coupling ratio. Through the simulation of these two cases,the detailed multiplexing capability was analyzed,and accordingly the experiments were also carried out. The simulation results showed that,the tailored formula enhances the multiplexing capability of the structure. In the first case, the maximum number of sensors which can be multiplexed is 8,and in the other case is 12 fiber optic sensors. The experimental results have a good agreement with numerical simulation results. Thus,it is considered expedient to incorporate RLT into large-scale building,grounds,bridges,dams,tunnels,highways and perimeter security.展开更多
Fiber optic Mach Zehnder interferometer(MZI) can be used as wavelength multiplexers and demultiplexers. The △ L and △ directly influence the properties of MZI. To lengthen the △ L can demultiplex much more wavelen...Fiber optic Mach Zehnder interferometer(MZI) can be used as wavelength multiplexers and demultiplexers. The △ L and △ directly influence the properties of MZI. To lengthen the △ L can demultiplex much more wavelengths, but when the △ L is longer, the temperature will influence MZI more seriously. A method to solve this problem is proposed, which enables MZI to work stably. The wavelength distance is 0.8 nm, and the extinction ratio is high.展开更多
According to the fact that the surface of liquid with low viscosity coefficient is a good reflection plane for a broadband light beam, liquid-level measurement in micrometer resolution is designed based on a fiber-opt...According to the fact that the surface of liquid with low viscosity coefficient is a good reflection plane for a broadband light beam, liquid-level measurement in micrometer resolution is designed based on a fiber-optic low coherence interferometer in Michelson configuration. The wave front of the reflected light beam is well enough to form an interferogram with a beam reflected from an optic mirror mounted on a stepping scanning-motor. The central peak of the interferogram is read as a measure of the liquid level. Experimental results show that this noncontact method can reach a resolution of ±1.25 μm in the measurement range of 86 mm.展开更多
A compact and high-resolution fiber-optic refractive index(RI)sensor based on a microwave photonic filter(MPF)is proposed and experimentally validated.The sensing head utilizes a cascaded in-line interferometer fabric...A compact and high-resolution fiber-optic refractive index(RI)sensor based on a microwave photonic filter(MPF)is proposed and experimentally validated.The sensing head utilizes a cascaded in-line interferometer fabricated by an input single-mode fiber(SMF)tapered fusion with no-core fiber-thin-core fiber(TCF)-SMF.The surrounding RI(SRI)can be demodulated by tracing the passband’s central frequency of the MPF,which is constructed by the cascaded in-line interferometer,electro-optic modulator,and a section of dispersion compensation fiber.The sensitivity of the sensor is tailorable through the use of different lengths of TCF.Experimental results reveal that with a 30 mm length of TCF,the sensor achieves a maximum theoretical sensitivity and resolution of-1.403 GHz∕refractive index unit eRIUT and 1.425×10^(-7) RIU,respectively,which is at least 6.3 times higher than what has been reported previously.Furthermore,the sensor exhibits temperature-insensitive characteristics within the range of 25℃-75℃,with a temperatureinduced frequency change of only±1.5 MHz.This value is significantly lower than the frequency change induced by changes in the SRI.The proposed MPF-based cascaded in-line interferometer RI sensor possesses benefits such as easy manufacture,low cost,high resolution,and temperature insensitivity.展开更多
Interferometry is a crucial investigative technique used across diverse fields to achieve highprecision measurements.It works by analyzing the phase difference between two interfering waves,which results from variatio...Interferometry is a crucial investigative technique used across diverse fields to achieve highprecision measurements.It works by analyzing the phase difference between two interfering waves,which results from variations in optical path lengths within an interferometer.We introduce a novel method for directly measuring changes in the phase difference within an optical interferometer,importantly,with the added advantage of a controllable enhancement factor.This approach is achieved through a two-step process:first,the optical phase difference is encoded into a sub-GHz radiofrequency(RF)signal using microwave-photonic manipulation;then,RF interferometry-assisted phase amplification is implemented at the destructive interference point.In our experiments,we demonstrate a phase sensitivity of 2.14 rad∕nm operating at 140 MHz using a miniature in-fiber Fabry-Pérot interferometer for sub-nanometer displacement sensing,which reveals a sensitivity magnification factor of 258.6.With further refinement,we anticipate that even higher enhancement factors can be achieved,paving the way for the development of cost-effective,ultrasensitive interferometry-based instruments for high-precision optical measurements.展开更多
A novel near-infrared all-fiber mode monitor based on a mini-two-path Mach-Zehnder interferometer(MTP-MZI)is proposed.The MTP-MZI mode monitor is created by fusing a section of(no-core fiber,NCF)and a(single-mode fibe...A novel near-infrared all-fiber mode monitor based on a mini-two-path Mach-Zehnder interferometer(MTP-MZI)is proposed.The MTP-MZI mode monitor is created by fusing a section of(no-core fiber,NCF)and a(single-mode fiber,SMF)together with an optical fiber fusion splicer,establishing two distinct centimeter-level optical transmission paths.Since the high-order modes in NCF transmit near-infrared light more sensitively to curvature-induced energy leakage than the fundamental mode in SMF,the near-infrared high-order mode light leaks out of NCF when the curvature changes,causing the MTP-MZI transmission spectrum to change.By ana⁃lyzing the relationship between the curvature,transmission spectrum,and spatial frequency spectrum,the modes involved in the interference can be studied,thereby revealing the mode transmission characteristics of near-infra⁃red light in optical fibers.In the verification experiments,higher-order modes were excited by inserting a novel hollow-core fiber(HCF)into the MTP-MZI.When the curvature of the MTP-MZI changes,the near-infrared light high-order mode introduced into the device leaks out,causing the transmission spectrum to return to its origi⁃nal state before bending and before the HCF was spliced.The experimental results demonstrate that the MTP-MZI mode monitor can monitor the fiber modes introduced from the external environment,providing both theoretical and experimental foundations for near-infrared all-fiber mode monitoring in optical information systems.展开更多
An optical fiber dual Fabry-Perot interferometric carbon monoxide gas sensor based on PANI/Co3 O4/GO(PCG)sensing membrane coated on the end face of the optical fiber is proposed and fabricated.One end face of photonic...An optical fiber dual Fabry-Perot interferometric carbon monoxide gas sensor based on PANI/Co3 O4/GO(PCG)sensing membrane coated on the end face of the optical fiber is proposed and fabricated.One end face of photonic crystal fiber(PCF)without cut-off wavelength is fused with a single-mode fiber(SMF),and the other end face of the PCF is coated with PCG sensing membrane.The collapsed layer formed during the air hole fusion of PCF is used as the first reflector,the interface between PCF and sensing membrane is used as the second reflector,and the interface between the sensing membrane and the air is used as the third reflector,thus the dual Fabry-Pe rot structure sensor is formed.The results show that the sensor has excellent sensitivity and selectivity to carbon monoxide.With the increasing concentration of carbon monoxide gas in the range of 0-60 ppm,the intensity of interference spectrum decreases.The sensitivity of the sensor is 0.3473 dB m/ppm,and its linearity is good.The response time and recovery time are 68 s and 106 s,respectively.The sensor has the advantages of the compact size,low cost,high sensitivity,strong selectivity and simple structure.It is suitable for the sensing detection of low concentration carbon monoxide gas.展开更多
Ultrasonic neuromodulation has gained recognition as a promising therapeutic approach.A miniature transducer capable of generating suitable-strength and broadband ultrasound is of great significance for achieving high...Ultrasonic neuromodulation has gained recognition as a promising therapeutic approach.A miniature transducer capable of generating suitable-strength and broadband ultrasound is of great significance for achieving high spatial precision ultrasonic neural stimulation.However,the ultrasound transducer with the above integrated is yet to be challenged.Here,we developed a fiber-optic photoacoustic emitter(FPE)with a diameter of 200μm,featuring controllable sound intensity and a broadband response(−6 dB bandwidth:162%).The device integrates MXene(Ti_(3)C_(2)Tx),known for its exceptional photothermal properties,and polydimethylsiloxane,which offers a high thermal expansion coefficient.This FPE,exhibiting high spatial precision(lateral:163.3μm,axial:207μm),is capable of selectively activating neurons in targeted regions.Using the TetTagging method to selectively express a cfos-promoter-inducible mCHERRY gene within the medial prefrontal cortex(mPFC),we found that photoacoustic stimulation significantly and temporarily activated the neurons.In vivo fiber photometry demonstrated that photoacoustic stimulation induced substantial calcium transients in mPFC neurons.Furthermore,we confirmed that photoacoustic stimulation of the mPFC using FPE markedly alleviates acute social defeat stress-induced emotional stress in mice.This work demonstrates the potential of FPEs for clinical applications,with a particular focus on modulating neural activity to regulate emotions.展开更多
According to the measurement principle of the traditional interferometer,a narrowband signal model is established and used,however,for wideband signals or multiple signals,this model is invalid.For the problems of dir...According to the measurement principle of the traditional interferometer,a narrowband signal model is established and used,however,for wideband signals or multiple signals,this model is invalid.For the problems of direction finding with interferometer for wideband signals and multiple signals scene,a frequency domain phase interferometer is proposed and the concrete implementation scheme is given.The proposed method computes the phase difference in frequency domain,and finds multi-target results with judging the spectrum amplitude changing,and uses the frequency phase difference to compute the arrival angle.Theoretical analysis and simulation results show that the proposed method effectively solves the problem of the angle estimation with phase interferometer for wideband signals,and has good performance in multiple signals scene with nonoverlapping spectrum or partially overlapping.In addition,the wider the signal bandwidth,the better direction finding performance of this algorithm.展开更多
Accurate and real-time detection of hydrogen(H_(2))is essential for ensuring energy security.Fiber-optic H_(2) sensors are gaining attention for their integration and remote sensing capabilities.However,they face chal...Accurate and real-time detection of hydrogen(H_(2))is essential for ensuring energy security.Fiber-optic H_(2) sensors are gaining attention for their integration and remote sensing capabilities.However,they face challenges,including complex fabrication processes and limited response times.Here,we propose a fiber-optic H_(2) sensing tip based on Tamm plasmon polariton(TPP)resonance,consisting of a multilayer metal/dielectric Bragg reflector deposited directly on the fiber end facet,simplifying the fabrication process.The fiber-optic TPP(FOTPP)tip exhibits both TPP and multiple Fabry-Perot(FP)resonances simultaneously,with the TPP employed for highly sensitive H_(2) detection.Compared to FP resonance,TPP exhibits more than twice the sensitivity under the same structural dimension without cavity geometry deformation.The excellent performance is attributed to alterations in phase-matching conditions,driven by changes in penetration depth of TPP.Furthermore,the FP mode is utilized to achieve an efficient photothermal effect to catalyze the reaction between H_(2) and the FOTPP structure.Consequently,the response and recovery speeds of the FOTPP tip under resonance-enhanced photothermal assistance are improved by 6.5 and 2.1 times,respectively.Our work offers a novel strategy for developing TPP-integrated fiber-optic tips,refines the theoretical framework of photothermal-assisted detection systems,and provides clear experimental evidence.展开更多
In x-ray dark-field imaging using dual phase grating interferometer,multi-contrast signals are extracted from a set of acquired phase-stepping data by using the least-squares fitting algorithm.The extracted mean inten...In x-ray dark-field imaging using dual phase grating interferometer,multi-contrast signals are extracted from a set of acquired phase-stepping data by using the least-squares fitting algorithm.The extracted mean intensity,amplitude and visibility signals may be intrinsically biased.However,it is still unclear how large these biases are and how the data acquisition parameters influence the biases in the extracted signals.This work set out to address these questions.Analytical expressions of the biases of the extracted signals were theoretically derived by using a second-order Taylor series expansion.Extensive numerical simulations were performed to validate the theoretical results.It is illustrated that while the estimated mean intensity signal is always unbiased,the estimated amplitude and visibility signals are both positively biased.While the biases of the estimated amplitude signals are proportional to the inverse of the total number of phase steps,the biases of the estimated visibility signals are inversely proportional to the product of the total number of phase steps and the mean number of photons counted per phase step.Meanwhile,it is demonstrated that the dependence of the biases on the mean visibility is quite different from that of Talbot-Lau interferometer due to the difference in the intensity model.We expect that these results can be useful for data acquisition optimizations and interpretation of x-ray dark-field images.展开更多
Temporal optics,which enables lossless manipulation of ultrafast pulses,offers a new dimension for the regulation of quantum optical fields.In this paper,we established a temporal Fourier transform(TF)system based on ...Temporal optics,which enables lossless manipulation of ultrafast pulses,offers a new dimension for the regulation of quantum optical fields.In this paper,we established a temporal Fourier transform(TF)system based on a four-wave mixing(FWM)time lens and constructed a full quantum theoretical model for the resulting temporal SU(1,1)interferometer.This interferometer has high temporal resolution,can impose interference in both time and frequency domains,and is sensitive to the phase derivative.By introducing linear time-varying phase modulation,we achieved sub-picosecond precision in temporal autocorrelation measurements and generatedan optical frequency comb with a fixed interval based on a feedback iteration mechanism.Theoretical analysis revealsthe crucial regulatory role of time-frequency coupling in quantum interference,providing novel solutions for ultrafast quantum imaging,temporal mode encoding,and the generation of optical frequency quantization.展开更多
基金supported by the National Natural Science Foundation of China(No.51278156)the Basic Project of Shenzhen Science & Technology Program(No.JCYJ2017030155815876)
文摘The interfacial debonding in fiber-reinforced plastic(FRP)strengthened repair material will affect the bonding strength and lead to failure of the repair without warning.Unfortunately the interfacial damage is normally invisible and often in the form of a patch rather than a through-width crack.Therefore,a debonding patch detection technique based on fiber optic interferometry is proposed.A quasi-impulse loading is applied with a rubberhead hammer and the total elongation of a surface-mounted optical fiber along the length of the repair material is measured as a function of load position.When a debonding patch is present,the induced sudden slope or sign change on the plot of fiber integral strain v.s.load position will reveal the extent and the location of the debonded area.The results of the study indicate that the proposed technique is applicable for debonding patch detection in repaired members under various support conditions.
基金support by National Natural Science Foundation of China (Nos. 51606158, 12104402)
文摘Fiber-optic sensing technology has the advantages of passivity, anti-electromagnetic interference, longdistancemeasurement, high sensitivity and high accuracy, small size, and adaptability to harsh environments such ashigh-vacuum, high-pressure, and strong magnetic fields compared with the traditional electrical sensing technology.However, with the increasing application requirements, how to further improve the sensitivity of fiber-optic sensors,extend the detection limit and improve the maintenance-free capability has become one of the core issues of thecurrent research. This paper reviews the principle, preparation, and application of fiber-optic microstructured sensingbased on abrupt field type. It specifically outlines the development and applications of micro-nano optical fibers,photonic crystal optical fibers, optical fiber gratings and structured optical fibers, and lists the main preparationmethods of two types of micro-nano optical fibers from the basic theory of optical fiber microstructured sensordevices.
基金supported by the National Key Laboratory of Plasma Physics,Laser Fusion Research Center,China Academy of Engineering Physics under the National Natural Science Foundation of China(Grant Nos.12127810 and 12475242).
文摘Laser-driven inertial confinement fusion(ICF)is an important experimental platform for high-energy-density physics research under extreme conditions.In ICF research,high-quality shock waves are key to fusion energy release.The velocity interferometer system for any reflector(VISAR)is the most important diagnostic technique for measuring quantities such as shock wave and particle velocities with high precision and high spatiotemporal resolution.This paper provides a detailed introduction to the various configurations of VISAR on 10 and 100 kJ-level laser facilities in China,including Line VISAR,Dual-Axis VISAR,Wide-Angle VISAR,and Compressed Ultrafast Photography-VISAR.Recent advances and applications of VISAR diagnostics at these laser facilities are presented,and the future trend of development of high-spatiotemporal-resolution velocity diagnostic technology is described.
文摘Ultrasound neuromodulation offers a non-invasive approach to modulate neural activity in the central nervous system.Precise,minimally invasive devices capable of targeted stimulation remain limited.A 200μm diameter fiber-optic photoacoustic emitter(FPE)was developed,coated with a MXene(Ti3C2Tx)and polydimethylsiloxane composite to generate controllable,broadband ultrasonic waves with high spatial precision.Using this FPE to stimulate the medial prefrontal cortex in mice,it was observed marked alleviation of acute social defeat stress-induced emotional stress,evidenced by reduced anxiety-like behavior and increased social interaction.This approach enables near-field,broadband,and tunable ultrasound neuromodulation with potential applications in treating neuropsychiatric disorders involving emotional regulation.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12104193 and U24A2017)National Undergraduate Training Program for Innovation and Entrepreneurship(Grant No.202411463037Z)the project of Changzhou Physics Society Fund(Grant No.CW20250102)。
文摘We theoretically investigate the phase sensitivity of a truncated SU(1,1)interferometer fed with a two-mode coherent state and employing double-port homodyne detection.On the one hand,we analytically demonstrate that the two-mode coherent state provides better phase sensitivity than the single-mode coherent state.In addition,we show that the doubleport homodyne detection is a quasi-optimal measurement.For a bright coherent-state input,the sensitivity of this scheme saturates the phase-sensitivity bound determined by the quantum Fisher information.On the other hand,we quantitatively illustrate the advantage of double-port homodyne detection over the single-port scheme under ideal conditions and in the presence of photon loss,respectively.Furthermore,our analysis indicates that the scheme we propose is robust against photon loss.
基金partially supported by the National Natural Science Foundation of China(Nos.61901494,62101563)。
文摘Rotating Single-Baseline Interferometer(RSBI)systems have attracted considerable attention for Direct Position Determination(DPD)due to their simplicity and high localization accuracy.Nevertheless,the growing complexity of electromagnetic environments has led to scenarios with multiple time-frequency aliased sources,rendering conventional DPD methods for RSBI systems ineffective.Previous studies have predominantly concentrated on deploying antenna arrays and applying related signal-processing techniques for localization.Typically,these approaches necessitate that the number of physical antennas exceeds the number of sources.For RSBI systems already in practical operation,this would entail the installation of additional physical antennas,which implies equipment recycling and hardware upgrades.In numerous cases,such modifications are unfeasible.This paper proposes a novel Relative Offset-based Direct Position Determination(RO-DPD)method for RSBI systems that can handle multiple time-frequency aliased sources.The proposed method overcomes the challenge of simultaneous positioning without requiring hardware modifications by leveraging time accumulation and algorithmic enhancements.The implementation of the method involves three key steps.Firstly,the rotation of the interferometer is synthesized into a virtual Uniform Circular Array(UCA).Secondly,a novel estimation variable,termed relative offset,is introduced.The variable serves as an intermediate parameter to establish correlation equations between the positions of multiple time-frequency aliased sources and the intercepted signals.Thirdly,the relative offset model in the UCA is transformed into a virtual Uniform Linear Array(ULA)model,from which the cost function can be derived via the Spatial Smoothing(SS)MUSIC algorithm.Theoretical analysis and simulation results verify the effectiveness of the proposed method.Compared with traditional approaches,the RO-DPD method maintains the low complexity of RSBI systems while demonstrating robust performance in complex electromagnetic environments.
基金Project supported by the National Key Research and Development Program of China(Grant No.2020YFC2200100)the CAS's Strategic Pioneer Program on Space Science(Grant No.XDA1502110201)。
文摘Tilt-to-length(TTL)coupling noise is a critical issue in space-based gravitational wave detection due to its complex dependence on multiple interacting factors,which complicates the identification of dominant parameters.To address this challenge,we develop a simulation model of the Taiji scientific interferometer,generating noise datasets under multiparameter conditions.Given the uniqueness of the telescope as well as the convergence behavior of the algorithm,the analysis is structured hierarchically:(i)the telescope level and(ii)the optical bench level.A hierarchical framework combining XGBoost and SHapley Additive exPlanations(SHAP)values is employed to model the intricate relationships between parameters and TTL coupling noise,supplemented by sensitivity analysis.Our results identify pointing jitter and telescope radius as the dominant parameters at the telescope level,while the angles of the plane mirrors and beam splitters are most influential at the optical bench level.The parameter space is reduced from 86 dimensions to 14 dimensions without sacrificing model accuracy.This approach offers actionable insights for optimizing the Taiji interferometer design.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61735014,61327012,and 61275088)the Scientific Research Program Funded by Shaanxi Provincial Education Department,China(Grant No.08JZ58)the Northwest University Graduate Innovation and Creativity Funds,China(Grant No.YZZ17088)
文摘An ultrasonic sensitivity-improved fiber-optic Fabry-Perot interferometer （FPI） is proposed and employed for ultra- sonic imaging of seismic physical models （SPMs）. The FPI comprises a flexible ultra-thin gold film and the end face of a graded-index multimode fiber （MMF）, both of which are enclosed in a ceramic tube. The MMF in a specified length can collimate the diverged light beam and compensate for the light loss inside the air cavity, leading to an increased spectral fringe visibility and thus a steeper spectral slope. By using the spectral sideband filtering technique, the collimated FP1 shows an improved ultrasonic response. Moreover, two-dimensional images of two SPMs are achieved in air by recon- structing the pulse-echo signals through using the time-of-flight approach. The proposed sensor with easy fabrication and compact size can be a good candidate for high-sensitivity and high-precision nondestructive testing of SPMs.
基金Sponsored by the Natural Science Foundation of Heilongjiang Province (Grant No. QC2012C081)the Creative Qualified Scientists and Technicians Foundation of Harbin City (Grant No. RC2012QN001025)the National Natural Science Foundation of China (Grant No. 61107069 and 41174161)
文摘In order to improve the multiplexing capability of the optical sensors based on the lower interferential optic fiber sensing technology and the white light fiber-optic Mach-Zehnder interferometer,reflective ladder topology network ( RLT) with tailored formula was proposed. The topology network consists of 6 rungs sensing elements linked by 5 couplers. Two cases with different choices of couplers were contrasted: one is equal coupling ratio,and the other is tailored coupling ratio. Through the simulation of these two cases,the detailed multiplexing capability was analyzed,and accordingly the experiments were also carried out. The simulation results showed that,the tailored formula enhances the multiplexing capability of the structure. In the first case, the maximum number of sensors which can be multiplexed is 8,and in the other case is 12 fiber optic sensors. The experimental results have a good agreement with numerical simulation results. Thus,it is considered expedient to incorporate RLT into large-scale building,grounds,bridges,dams,tunnels,highways and perimeter security.
文摘Fiber optic Mach Zehnder interferometer(MZI) can be used as wavelength multiplexers and demultiplexers. The △ L and △ directly influence the properties of MZI. To lengthen the △ L can demultiplex much more wavelengths, but when the △ L is longer, the temperature will influence MZI more seriously. A method to solve this problem is proposed, which enables MZI to work stably. The wavelength distance is 0.8 nm, and the extinction ratio is high.
基金Dalian Science and Technology Foundation and National Science Foundation(30470416)
文摘According to the fact that the surface of liquid with low viscosity coefficient is a good reflection plane for a broadband light beam, liquid-level measurement in micrometer resolution is designed based on a fiber-optic low coherence interferometer in Michelson configuration. The wave front of the reflected light beam is well enough to form an interferogram with a beam reflected from an optic mirror mounted on a stepping scanning-motor. The central peak of the interferogram is read as a measure of the liquid level. Experimental results show that this noncontact method can reach a resolution of ±1.25 μm in the measurement range of 86 mm.
基金supported by the National Natural Science Foundation of China(Grant No.61975167).
文摘A compact and high-resolution fiber-optic refractive index(RI)sensor based on a microwave photonic filter(MPF)is proposed and experimentally validated.The sensing head utilizes a cascaded in-line interferometer fabricated by an input single-mode fiber(SMF)tapered fusion with no-core fiber-thin-core fiber(TCF)-SMF.The surrounding RI(SRI)can be demodulated by tracing the passband’s central frequency of the MPF,which is constructed by the cascaded in-line interferometer,electro-optic modulator,and a section of dispersion compensation fiber.The sensitivity of the sensor is tailorable through the use of different lengths of TCF.Experimental results reveal that with a 30 mm length of TCF,the sensor achieves a maximum theoretical sensitivity and resolution of-1.403 GHz∕refractive index unit eRIUT and 1.425×10^(-7) RIU,respectively,which is at least 6.3 times higher than what has been reported previously.Furthermore,the sensor exhibits temperature-insensitive characteristics within the range of 25℃-75℃,with a temperatureinduced frequency change of only±1.5 MHz.This value is significantly lower than the frequency change induced by changes in the SRI.The proposed MPF-based cascaded in-line interferometer RI sensor possesses benefits such as easy manufacture,low cost,high resolution,and temperature insensitivity.
基金support from the Roy A.Wilkens Professorship Endowment。
文摘Interferometry is a crucial investigative technique used across diverse fields to achieve highprecision measurements.It works by analyzing the phase difference between two interfering waves,which results from variations in optical path lengths within an interferometer.We introduce a novel method for directly measuring changes in the phase difference within an optical interferometer,importantly,with the added advantage of a controllable enhancement factor.This approach is achieved through a two-step process:first,the optical phase difference is encoded into a sub-GHz radiofrequency(RF)signal using microwave-photonic manipulation;then,RF interferometry-assisted phase amplification is implemented at the destructive interference point.In our experiments,we demonstrate a phase sensitivity of 2.14 rad∕nm operating at 140 MHz using a miniature in-fiber Fabry-Pérot interferometer for sub-nanometer displacement sensing,which reveals a sensitivity magnification factor of 258.6.With further refinement,we anticipate that even higher enhancement factors can be achieved,paving the way for the development of cost-effective,ultrasensitive interferometry-based instruments for high-precision optical measurements.
基金Supported by the Central Government Guidance on Local Science and Technology Development Funds(2023ZY1023)the Six Talent Peaks Project in Jiangsu Province(KTHY-052).
文摘A novel near-infrared all-fiber mode monitor based on a mini-two-path Mach-Zehnder interferometer(MTP-MZI)is proposed.The MTP-MZI mode monitor is created by fusing a section of(no-core fiber,NCF)and a(single-mode fiber,SMF)together with an optical fiber fusion splicer,establishing two distinct centimeter-level optical transmission paths.Since the high-order modes in NCF transmit near-infrared light more sensitively to curvature-induced energy leakage than the fundamental mode in SMF,the near-infrared high-order mode light leaks out of NCF when the curvature changes,causing the MTP-MZI transmission spectrum to change.By ana⁃lyzing the relationship between the curvature,transmission spectrum,and spatial frequency spectrum,the modes involved in the interference can be studied,thereby revealing the mode transmission characteristics of near-infra⁃red light in optical fibers.In the verification experiments,higher-order modes were excited by inserting a novel hollow-core fiber(HCF)into the MTP-MZI.When the curvature of the MTP-MZI changes,the near-infrared light high-order mode introduced into the device leaks out,causing the transmission spectrum to return to its origi⁃nal state before bending and before the HCF was spliced.The experimental results demonstrate that the MTP-MZI mode monitor can monitor the fiber modes introduced from the external environment,providing both theoretical and experimental foundations for near-infrared all-fiber mode monitoring in optical information systems.
基金supported by the National Natural Science Foundation of China(No.51574054)the University Innovation Team Building Program of Chongqing(No.CXTDX201601030)+2 种基金Scientific and Technological Research Program of Chongqing Municipal Education Commission(No.KJZD-M201901102)Chongqing Science and Technology Bureau(Nos.cstc2017shmsA20017,cstc2018jcyjAX0294,CSTCCXLJRC 201905)the Innovation Leader Project of Chongqing Science and Technology Bureau(No.CSTCCXLJRC201905)。
文摘An optical fiber dual Fabry-Perot interferometric carbon monoxide gas sensor based on PANI/Co3 O4/GO(PCG)sensing membrane coated on the end face of the optical fiber is proposed and fabricated.One end face of photonic crystal fiber(PCF)without cut-off wavelength is fused with a single-mode fiber(SMF),and the other end face of the PCF is coated with PCG sensing membrane.The collapsed layer formed during the air hole fusion of PCF is used as the first reflector,the interface between PCF and sensing membrane is used as the second reflector,and the interface between the sensing membrane and the air is used as the third reflector,thus the dual Fabry-Pe rot structure sensor is formed.The results show that the sensor has excellent sensitivity and selectivity to carbon monoxide.With the increasing concentration of carbon monoxide gas in the range of 0-60 ppm,the intensity of interference spectrum decreases.The sensitivity of the sensor is 0.3473 dB m/ppm,and its linearity is good.The response time and recovery time are 68 s and 106 s,respectively.The sensor has the advantages of the compact size,low cost,high sensitivity,strong selectivity and simple structure.It is suitable for the sensing detection of low concentration carbon monoxide gas.
基金supported by the National Nature Science Foundation of China(Grant Number:U24A20306,12102140,6227031087,62035006,and 6207030117).
文摘Ultrasonic neuromodulation has gained recognition as a promising therapeutic approach.A miniature transducer capable of generating suitable-strength and broadband ultrasound is of great significance for achieving high spatial precision ultrasonic neural stimulation.However,the ultrasound transducer with the above integrated is yet to be challenged.Here,we developed a fiber-optic photoacoustic emitter(FPE)with a diameter of 200μm,featuring controllable sound intensity and a broadband response(−6 dB bandwidth:162%).The device integrates MXene(Ti_(3)C_(2)Tx),known for its exceptional photothermal properties,and polydimethylsiloxane,which offers a high thermal expansion coefficient.This FPE,exhibiting high spatial precision(lateral:163.3μm,axial:207μm),is capable of selectively activating neurons in targeted regions.Using the TetTagging method to selectively express a cfos-promoter-inducible mCHERRY gene within the medial prefrontal cortex(mPFC),we found that photoacoustic stimulation significantly and temporarily activated the neurons.In vivo fiber photometry demonstrated that photoacoustic stimulation induced substantial calcium transients in mPFC neurons.Furthermore,we confirmed that photoacoustic stimulation of the mPFC using FPE markedly alleviates acute social defeat stress-induced emotional stress in mice.This work demonstrates the potential of FPEs for clinical applications,with a particular focus on modulating neural activity to regulate emotions.
文摘According to the measurement principle of the traditional interferometer,a narrowband signal model is established and used,however,for wideband signals or multiple signals,this model is invalid.For the problems of direction finding with interferometer for wideband signals and multiple signals scene,a frequency domain phase interferometer is proposed and the concrete implementation scheme is given.The proposed method computes the phase difference in frequency domain,and finds multi-target results with judging the spectrum amplitude changing,and uses the frequency phase difference to compute the arrival angle.Theoretical analysis and simulation results show that the proposed method effectively solves the problem of the angle estimation with phase interferometer for wideband signals,and has good performance in multiple signals scene with nonoverlapping spectrum or partially overlapping.In addition,the wider the signal bandwidth,the better direction finding performance of this algorithm.
基金financial supports from National Key Research and Development Program of China(2023YFB3209500)National Natural Science Foundation of China(NSFC)(12274052 and 62171076)+1 种基金Fundamental Research Funds for the Central Universities(DUT24ZD203)Bolian Research Funds of Dalian Maritime University and Fundamental Research Funds for the Central Universities(3132024605).
文摘Accurate and real-time detection of hydrogen(H_(2))is essential for ensuring energy security.Fiber-optic H_(2) sensors are gaining attention for their integration and remote sensing capabilities.However,they face challenges,including complex fabrication processes and limited response times.Here,we propose a fiber-optic H_(2) sensing tip based on Tamm plasmon polariton(TPP)resonance,consisting of a multilayer metal/dielectric Bragg reflector deposited directly on the fiber end facet,simplifying the fabrication process.The fiber-optic TPP(FOTPP)tip exhibits both TPP and multiple Fabry-Perot(FP)resonances simultaneously,with the TPP employed for highly sensitive H_(2) detection.Compared to FP resonance,TPP exhibits more than twice the sensitivity under the same structural dimension without cavity geometry deformation.The excellent performance is attributed to alterations in phase-matching conditions,driven by changes in penetration depth of TPP.Furthermore,the FP mode is utilized to achieve an efficient photothermal effect to catalyze the reaction between H_(2) and the FOTPP structure.Consequently,the response and recovery speeds of the FOTPP tip under resonance-enhanced photothermal assistance are improved by 6.5 and 2.1 times,respectively.Our work offers a novel strategy for developing TPP-integrated fiber-optic tips,refines the theoretical framework of photothermal-assisted detection systems,and provides clear experimental evidence.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U1532113,11475170,11905041)Anhui Provincial Natural Science Foundation(Grant No.2208085MA18)Fundamental Research Funds for the Central Universities(Grant No.JZ2022HGTB0244)。
文摘In x-ray dark-field imaging using dual phase grating interferometer,multi-contrast signals are extracted from a set of acquired phase-stepping data by using the least-squares fitting algorithm.The extracted mean intensity,amplitude and visibility signals may be intrinsically biased.However,it is still unclear how large these biases are and how the data acquisition parameters influence the biases in the extracted signals.This work set out to address these questions.Analytical expressions of the biases of the extracted signals were theoretically derived by using a second-order Taylor series expansion.Extensive numerical simulations were performed to validate the theoretical results.It is illustrated that while the estimated mean intensity signal is always unbiased,the estimated amplitude and visibility signals are both positively biased.While the biases of the estimated amplitude signals are proportional to the inverse of the total number of phase steps,the biases of the estimated visibility signals are inversely proportional to the product of the total number of phase steps and the mean number of photons counted per phase step.Meanwhile,it is demonstrated that the dependence of the biases on the mean visibility is quite different from that of Talbot-Lau interferometer due to the difference in the intensity model.We expect that these results can be useful for data acquisition optimizations and interpretation of x-ray dark-field images.
文摘Temporal optics,which enables lossless manipulation of ultrafast pulses,offers a new dimension for the regulation of quantum optical fields.In this paper,we established a temporal Fourier transform(TF)system based on a four-wave mixing(FWM)time lens and constructed a full quantum theoretical model for the resulting temporal SU(1,1)interferometer.This interferometer has high temporal resolution,can impose interference in both time and frequency domains,and is sensitive to the phase derivative.By introducing linear time-varying phase modulation,we achieved sub-picosecond precision in temporal autocorrelation measurements and generatedan optical frequency comb with a fixed interval based on a feedback iteration mechanism.Theoretical analysis revealsthe crucial regulatory role of time-frequency coupling in quantum interference,providing novel solutions for ultrafast quantum imaging,temporal mode encoding,and the generation of optical frequency quantization.
