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
Landslide susceptibility mapping(LSM)is an essential tool for mitigating the escalating global risk of landslides.However,challenges such as the heterogeneity of different landslide triggers,extensive engineering acti...Landslide susceptibility mapping(LSM)is an essential tool for mitigating the escalating global risk of landslides.However,challenges such as the heterogeneity of different landslide triggers,extensive engineering activities exacerbated reactivation,and the interpretability of data-driven models have hindered the practical application of LSM.This work proposes a novel framework for enhancing LSM considering different triggers for accumulation and rock landslides,leveraging interpretable machine learning and Multi-temporal Interferometric Synthetic Aperture Radar(MT-InSAR)technology.Initially,a refined fieldinvestigation was conducted to delineate the accumulation and rock area according to landslide types,leading to the identificationof relevant contributing factors.Deformation along the slope was then combined with time-series analysis to derive a landslide activity level(AL)index to recognize the likelihood of reactivation or dormancy.The SHapley Additive exPlanation(SHAP)technique facilitated the interpretation of factors and the identificationof determinants in high susceptibility areas.The results indicate that random forest(RF)outperformed other models in both accumulation and rock areas.Key factors including thickness and weak intercalation were identifiedfor accumulation and rock landslides.The introduction of AL substantially enhanced the predictive capability of the LSM and outperformed models that neglect movement trends or deformation rates with an average ratio of 81.23%in high susceptibility zones.Besides,the fieldvalidation confirmedthat 83.8%of newly identifiedlandslides were correctly upgraded.Given its efficiencyand operational simplicity,the proposed hybrid model opens new avenues for the feasibility of enhancement in LSM at urban settlements worldwide.展开更多
We demonstrate a silicon nitride photonics-based imaging system that can perform one-dimensional interferometric imaging around the 1550-nm wavelength.The magnetograph using interferometric and computational imaging f...We demonstrate a silicon nitride photonics-based imaging system that can perform one-dimensional interferometric imaging around the 1550-nm wavelength.The magnetograph using interferometric and computational imaging for remote observations(MICRO)design uses silicon nitride on a Si platform to replace the bulky free-space optics of traditional magnetograph imaging systems with nanofabricated structures of a fraction of the size.The photonic integrated circuit(PIC)uses an array of lenslets that couple light into four input waveguides with spacing arranged along a Golomb ruler,where each aperture pair formed has a unique length.Each aperture is mixed with a 13-dBm reference laser and separated inside a 2×4 optical hybrid to generate in-phase and quadrature-phase signals to be detected in balanced detectors at the output of the PIC.We use a field programmable gate array(FPGA)board to digitize and process the measurements.The FPGAs and PIC are combined to reduce the overall size,weight,and power of the system,paving the way for a compact imaging system.We demonstrate a PIC-based imager design and experimental testbed for spectrometry applications.展开更多
Single-wavelength interferometry achieves high resolution for smooth surfaces but struggles with rough industrially relevant ones due to limited unambiguous measuring range and speckle effects.Multiwavelength interfer...Single-wavelength interferometry achieves high resolution for smooth surfaces but struggles with rough industrially relevant ones due to limited unambiguous measuring range and speckle effects.Multiwavelength interferometry addresses these challenges using synthetic wavelengths,enabling a balance between extended measurement range and resolution by combining several synthetic wavelengths.This approach holds immense potential for diverse industrial applications,yet it remains largely untapped due to the lack of suitable light sources.Existing solutions are constrained by limited flexibility in synthetic-wavelength generation and slow switching speeds.We demonstrate a light source for multiwavelength interferometry based on electro-optic single-sideband modulation.It reliably generates synthetic wavelengths with arbitrary values from centimeters to meters and switching time below 30 ms.This breakthrough paves the way for dynamic reconfigurable multiwavelength interferometry capable of adapting to complex surfaces and operating efficiently even outside laboratory settings.These capabilities unlock the full potential of multiwavelength interferometry,offering unprecedented flexibility and speed for industrial and technological applications.展开更多
Laser frequency combs,which are composed of a series of equally spaced coherent frequency components,have triggered revolutionary progress in precision spectroscopy and optical metrology.Length/distance is of fundamen...Laser frequency combs,which are composed of a series of equally spaced coherent frequency components,have triggered revolutionary progress in precision spectroscopy and optical metrology.Length/distance is of fundamental importance in both science and technology.We describe a ranging scheme based on chirped pulse interferometry.In contrast to the traditional spectral interferometry,the local oscillator is strongly chirped which is able to meet the measurement pulses at arbitrary distances,and therefore,the dead zones can be removed.The distances can be precisely determined via two measurement steps based on the time-of-flight method and synthetic wavelength interferometry,respectively.To overcome the speed limitation of the optical spectrum analyzer,the spectrograms are stretched and detected by a fast photodetector and oscilloscope and consequently mapped into the time domain in real time.The experimental results indicate that the measurement uncertainty can be well within±2μm,compared with the reference distance meter.The Allan deviation can reach 0.4μm at 4 ns averaging time and 25 nm at 1μs and can achieve 2 nm at 100μs averaging time.We also measured a spinning disk with grooves of different depths to verify the measurement speed,and the results show that the grooves with about 150 m∕s line speed can be clearly captured.Our method provides a unique combination of non-dead zones,ultrafast measurement speed,high precision and accuracy,large ambiguity range,and only one single comb source.This system could offer a powerful solution for field measurements in practical applications in the future.展开更多
Acoustic detection has many applications across science and technology from medicine to imaging and communications.However,most acoustic sensors have a common limitation in that the detection must be near the acoustic...Acoustic detection has many applications across science and technology from medicine to imaging and communications.However,most acoustic sensors have a common limitation in that the detection must be near the acoustic source.Alternatively,laser interferometry with picometer-scale motional displacement detection can rapidly and precisely measure sound-induced minute vibrations on remote surfaces.Here,we demonstrate the feasibility of sound detection up to 100 kHz at remote sites with≈60 m optical path length via laser homodyne interferometry.Based on our ultrastable hertz linewidth laser with 10-15 fractional stability,our laser interferometer achieves 0.5 pm/Hz1/2 displacement sensitivity near 10 kHz,bounded only by laser frequency noise over 10 kHz.Between 140 Hz and 15 kHz,we achieve a homodyne acoustic sensing sensitivity of subnanometer/Pascal across our conversational frequency overtones.The minimal sound pressure detectable over 60 m optical path length is≈2 mPa,with dynamic ranges over 100 dB.With the demonstrated standoff picometric distance metrology,we successfully detected and reconstructed musical scores of normal conversational volumes with high fidelity.The acoustic detection via this precision laser interferometer could be applied to selective area sound sensing for remote acoustic metrology,optomechanical vibrational motion sensing,and ultrasensitive optical microphones at the laser frequency noise limits.展开更多
Laser frequency microcombs provide a series of equidistant,coherent frequency markers across a broad spectrum,enabling advancements in laser spectroscopy,dense optical communications,precision distance metrology,and a...Laser frequency microcombs provide a series of equidistant,coherent frequency markers across a broad spectrum,enabling advancements in laser spectroscopy,dense optical communications,precision distance metrology,and astronomy.Here,we design and fabricate silicon nitride,dispersion-managed microresonators that effectively suppress avoided-mode crossings and achieve close-to-zero averaged dispersion.Both the stochastic noise and mode-locking dynamics of the resonator are numerically and experimentally investigated.First,we experimentally demonstrate thermally stabilized microcomb formation in the microresonator across different mode-locked states,showing negligible center frequency shifts and a broad frequency bandwidth.Next,we characterize the femtosecond timing jitter of the microcombs,supported by precise metrology of the timing phase and relative intensity noise.For the single-soliton state,we report a relative intensity noise of−153.2 dB∕Hz,close to the shot-noise limit,and a quantum-noise–limited timing jitter power spectral density of 0.4 as 2∕Hz at a 100 kHz offset frequency,measured using a self-heterodyne linear interferometer.In addition,we achieve an integrated timing jitter of 1.7 fs±0.07 fs,measured from 10 kHz to 1 MHz.Measuring and understanding these fundamental noise parameters in high clock rate frequency microcombs is critical for advancing soliton physics and enabling new applications in precision metrology.展开更多
Null compensation interferometry is the primary testing method for the manufacture of ultra-high-precision aspheric mirrors.The crosstalk fringes generated by stray light in interferometry can affect accuracy and pote...Null compensation interferometry is the primary testing method for the manufacture of ultra-high-precision aspheric mirrors.The crosstalk fringes generated by stray light in interferometry can affect accuracy and potentially prevent the testing from proceeding normally.Position errors include the decenter error,tilt error,and distance error.During the testing process,position errors will impact the testing accuracy and the crosstalk fringes generated by stray light.To determine the specific impact of position errors,we use the concept of Hindle shell testing of a convex aspheric mirror,and propose the simulation method of crosstalk fringes in null compensation interferometry.We also propose evaluation indices of crosstalk fringes in interferometry and simulate the influence of position errors on the crosstalk fringes.This work aims to help improve the design of compensation interferometry schemes,enhance the feasibility of the design,reduce engineering risks,and improve efficiency.展开更多
We propose a quantum-enhanced metrological scheme utilizing unbalanced entangled coherent states(ECSs) generated by passing a coherent state and a coherent state superposition through an unbalanced beam splitter(BS). ...We propose a quantum-enhanced metrological scheme utilizing unbalanced entangled coherent states(ECSs) generated by passing a coherent state and a coherent state superposition through an unbalanced beam splitter(BS). We identify the optimal phase sensitivity of this scheme by maximizing the quantum Fisher information(QFI) with respect to the BS transmission ratio. Our scheme outperforms the conventional scheme with a balanced BS, particularly in the presence of single-mode photon loss. Notably, our scheme retains quantum advantage in phase sensitivity in the limit of high photon intensity, where the balanced scheme offers no advantage over the classical strategy.展开更多
The Mach-Zehnder interferometer is a fundamental tool for measuring phase shifts between two light paths,serving as a crucial prototype for achieving high-precision measurements in various scientific and technological...The Mach-Zehnder interferometer is a fundamental tool for measuring phase shifts between two light paths,serving as a crucial prototype for achieving high-precision measurements in various scientific and technological applications.In this study,we analyze different models for estimating the relative phase shift in a general two-arm Mach-Zehnder interferometer.We demonstrated that single-parameter estimation models can be reduced from the two-parameter estimation model by imposing appropriate constraints on the parameter space.To make quantum Fisher information of the single-parameter estimation models meaningful,the corresponding constraints must be guaranteed in the experiment implementation.Furthermore,we apply the quantum Fisher information approach to analyze the Mach-Zehnder interferometer with the an input state composed of a displaced squeezed vacuum state and a coherent state,providing insights into the precision limits of such configurations.展开更多
Laser interferometry with higher resolution,faster update rate,and larger dynamic range is highly anticipated in the exploration of physics frontiers,advanced manufacturing,and precision sensing.Real-time dispersive s...Laser interferometry with higher resolution,faster update rate,and larger dynamic range is highly anticipated in the exploration of physics frontiers,advanced manufacturing,and precision sensing.Real-time dispersive spectral interferometry(DSI)shows promise for high-speed precision measurements,whereas the resolution of subnanometers has not yet been achieved.We present a comprehensive theoretical framework to analyze the limitations of real-time DSI based on the signal-to-noise ratio and data volume.A real-time orthogonal polarization spectral interferometry technique is proposed,which utilizes a pair of interferograms with the pi-phase shift to effectively mitigate the phase noise embedded in real-time spectral envelopes,thereby enabling the precise measurements with subnanometer resolution at megahertz frame rates.The recorded time series data are processed through interpolation,segmentation,time–frequency mapping,and de-enveloping to regain the typical cosine-shaped spectral evolution,followed by a fitting-based phase retrieval method to extract the interference phase.The phase resolution of 1.1 mrad(0.91 as for time delay and 0.3 nm for distance)is obtained at the update rate of 22.2 MHz even under the detection bandwidth of 500 MHz,and can be further enhanced to 0.29 mrad(0.24 as for time delay)after 500 times averaging(∼0.5 MHz).Our approach is validated through periodic phase modulations and applied to measure the rapid damped oscillations of a piezo stage,yielding results consistent with those obtained from a commercial picometer interferometer.展开更多
Microsphere assisted microscopy(MAM)has been rapidly developed to meet the measurement needs of microstructures.MAM can be integrated with optical interference microscopy(OIM)to achieve high lateral resolution surface...Microsphere assisted microscopy(MAM)has been rapidly developed to meet the measurement needs of microstructures.MAM can be integrated with optical interference microscopy(OIM)to achieve high lateral resolution surface profile measurement.However,the microspheres introduce intricate phase changes,resulting in optical path asymmetry which is very challenging to compensate for.This limitation constrains the application of MAM in OIM.In this paper,simulation analysis reveals that the phase transmission of the microsphere is influenced by parameters such as microsphere diameter and its relative position to the sample.It is concluded that a unique compensation process must be adopted for each individual microsphere.Addressing this issue,we proposed a phase compensation algorithm based on the three-dimensional position control of the microsphere and integrated it into our combined system of MAM and white light interferometry(WLI),reducing the phase errors introduced by the microspheres while enhancing the lateral resolution of optical system.This approach improved the profile measurement accuracy,offering a perspective for optically measuring the surface profile of intricate microstructures.展开更多
The semiconductor bridge(SCB)ignites through bridge film discharge,offering advantages such as low ignition energy,high safety,and compatibility with digital logic circuits.The study uses laser interferometry to inves...The semiconductor bridge(SCB)ignites through bridge film discharge,offering advantages such as low ignition energy,high safety,and compatibility with digital logic circuits.The study uses laser interferometry to investigate the gas dynamics of the bridge film after SCB plasma extinction.Interferometric images of the SCB film gas were obtained through a laser interferometry optical path.After the degradation model of digital image processing,clearer images were produced to facilitate analysis and calculation.The results show that the gas temperature at the center of the SCB film reaches a maximum of 1000 K,and the temperature rapidly decreases along the axial direction of the bridge surface to room temperature at 300 K.The maximum diffusion velocity of the plasma is 1.8 km/s.These findings provide critical insights for SCB design and ignition control.展开更多
In this paper,we image the subsurface reflectors by interferometric imaging using primary and downgoing first-order free-surface related multiple reflections in walkaway VSP data.By analyzing the stack fold distributi...In this paper,we image the subsurface reflectors by interferometric imaging using primary and downgoing first-order free-surface related multiple reflections in walkaway VSP data.By analyzing the stack fold distribution,we find that primary-direct interferometric imaging has a smaller image range,but its stack fold is higher near the well while ghostdirect interferometric imaging is the opposite.We try to solve this problem by the joint interferometric imaging of walkaway VSP data,combining primary-direct interferometric imaging with ghost-direct interferometric imaging.In this way,we can effectively widen the imaging range,simultaneously increase the fold（especially near the well）,suppress spurious interference,and improve the image SNR,so that we can get a more credible image.Test results on synthetic walkaway VSP data and field data show that joint interferometric imaging is very effective.展开更多
In order to suppress the airwave noise in marine controlled-source electromagnetic （CSEM） data, we propose a 3D deconvolution （3DD） interferometry method with a synthetic aperture source and obtain the relative an...In order to suppress the airwave noise in marine controlled-source electromagnetic （CSEM） data, we propose a 3D deconvolution （3DD） interferometry method with a synthetic aperture source and obtain the relative anomaly coefficient （RAC） of the EM field reflection responses to show the degree for suppressing the airwave. We analyze the potential of the proposed method for suppressing the airwave, and compare the proposed method with traditional methods in their effectiveness. A method to select synthetic source length is derived and the effect of the water depth on RAC is examined via numerical simulations. The results suggest that 3DD interferometry method with a synthetic source can effectively suppress the airwave and enhance the potential of marine CSEM to hydrocarbon exploration.展开更多
选取厦门新机场填海区为研究对象,收集2016年12月至2018年11月期间的56景升轨Sentinel-1雷达影像,采用多时相In SAR(Multi-temporal In SAR,MT-InSAR)技术,获取了填海区由软土层固结压缩引起的沉降场。针对不同填海时间的场地,探讨其形...选取厦门新机场填海区为研究对象,收集2016年12月至2018年11月期间的56景升轨Sentinel-1雷达影像,采用多时相In SAR(Multi-temporal In SAR,MT-InSAR)技术,获取了填海区由软土层固结压缩引起的沉降场。针对不同填海时间的场地,探讨其形变特征及原因,并对比分析了In SAR监测结果与同期水准测量结果。结果表明,一期填海区沉降主要发生在2017年6月份以前,后期已趋于平稳,监测点最大沉降速率为-43.6mm/yr;二期填海区场地整体表现出不同程度的沉降,主要沉降区位于新近完成填海的区域,监测点最大沉降速率为-129.1mm/yr,且场地沉降量与淤泥厚度之间具有较高的正相关性。同时In SAR与水准数据具有较高的一致性,验证了MT-InSAR技术在填海区沉降监测方面的适用性,后续可为机场沉降灾害的预防和控制提供科学依据。展开更多
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 National Key R&D Program of China(Grant No.2023YFC3007201)the National Natural Science Foundation of China(Grant No.42377161)the Opening Fund of Key Laboratory of Geological Survey and Evaluation of Ministry of Education(Grant No.GLAB 2024ZR03).
文摘Landslide susceptibility mapping(LSM)is an essential tool for mitigating the escalating global risk of landslides.However,challenges such as the heterogeneity of different landslide triggers,extensive engineering activities exacerbated reactivation,and the interpretability of data-driven models have hindered the practical application of LSM.This work proposes a novel framework for enhancing LSM considering different triggers for accumulation and rock landslides,leveraging interpretable machine learning and Multi-temporal Interferometric Synthetic Aperture Radar(MT-InSAR)technology.Initially,a refined fieldinvestigation was conducted to delineate the accumulation and rock area according to landslide types,leading to the identificationof relevant contributing factors.Deformation along the slope was then combined with time-series analysis to derive a landslide activity level(AL)index to recognize the likelihood of reactivation or dormancy.The SHapley Additive exPlanation(SHAP)technique facilitated the interpretation of factors and the identificationof determinants in high susceptibility areas.The results indicate that random forest(RF)outperformed other models in both accumulation and rock areas.Key factors including thickness and weak intercalation were identifiedfor accumulation and rock landslides.The introduction of AL substantially enhanced the predictive capability of the LSM and outperformed models that neglect movement trends or deformation rates with an average ratio of 81.23%in high susceptibility zones.Besides,the fieldvalidation confirmedthat 83.8%of newly identifiedlandslides were correctly upgraded.Given its efficiencyand operational simplicity,the proposed hybrid model opens new avenues for the feasibility of enhancement in LSM at urban settlements worldwide.
基金supported by the National Aeronautics and Space Administration(Grant No.80NSSC20K0914)the Lockheed Martin Internal Research Funds(IRAD).
文摘We demonstrate a silicon nitride photonics-based imaging system that can perform one-dimensional interferometric imaging around the 1550-nm wavelength.The magnetograph using interferometric and computational imaging for remote observations(MICRO)design uses silicon nitride on a Si platform to replace the bulky free-space optics of traditional magnetograph imaging systems with nanofabricated structures of a fraction of the size.The photonic integrated circuit(PIC)uses an array of lenslets that couple light into four input waveguides with spacing arranged along a Golomb ruler,where each aperture pair formed has a unique length.Each aperture is mixed with a 13-dBm reference laser and separated inside a 2×4 optical hybrid to generate in-phase and quadrature-phase signals to be detected in balanced detectors at the output of the PIC.We use a field programmable gate array(FPGA)board to digitize and process the measurements.The FPGAs and PIC are combined to reduce the overall size,weight,and power of the system,paving the way for a compact imaging system.We demonstrate a PIC-based imager design and experimental testbed for spectrometry applications.
基金supported by the German Federal Ministry of Education and Research,Research Program Quantum Systems(Grant No.13N16774).
文摘Single-wavelength interferometry achieves high resolution for smooth surfaces but struggles with rough industrially relevant ones due to limited unambiguous measuring range and speckle effects.Multiwavelength interferometry addresses these challenges using synthetic wavelengths,enabling a balance between extended measurement range and resolution by combining several synthetic wavelengths.This approach holds immense potential for diverse industrial applications,yet it remains largely untapped due to the lack of suitable light sources.Existing solutions are constrained by limited flexibility in synthetic-wavelength generation and slow switching speeds.We demonstrate a light source for multiwavelength interferometry based on electro-optic single-sideband modulation.It reliably generates synthetic wavelengths with arbitrary values from centimeters to meters and switching time below 30 ms.This breakthrough paves the way for dynamic reconfigurable multiwavelength interferometry capable of adapting to complex surfaces and operating efficiently even outside laboratory settings.These capabilities unlock the full potential of multiwavelength interferometry,offering unprecedented flexibility and speed for industrial and technological applications.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFC2204601)the National Natural Science Foundation of China(Grant Nos.11925503 and 12275093)+1 种基金the Natural Science Foundation of Hubei Province(Grant No.2021CFB019)the State Key Laboratory of Applied Optics(Grant No.SKLAO2022001A10).
文摘Laser frequency combs,which are composed of a series of equally spaced coherent frequency components,have triggered revolutionary progress in precision spectroscopy and optical metrology.Length/distance is of fundamental importance in both science and technology.We describe a ranging scheme based on chirped pulse interferometry.In contrast to the traditional spectral interferometry,the local oscillator is strongly chirped which is able to meet the measurement pulses at arbitrary distances,and therefore,the dead zones can be removed.The distances can be precisely determined via two measurement steps based on the time-of-flight method and synthetic wavelength interferometry,respectively.To overcome the speed limitation of the optical spectrum analyzer,the spectrograms are stretched and detected by a fast photodetector and oscilloscope and consequently mapped into the time domain in real time.The experimental results indicate that the measurement uncertainty can be well within±2μm,compared with the reference distance meter.The Allan deviation can reach 0.4μm at 4 ns averaging time and 25 nm at 1μs and can achieve 2 nm at 100μs averaging time.We also measured a spinning disk with grooves of different depths to verify the measurement speed,and the results show that the grooves with about 150 m∕s line speed can be clearly captured.Our method provides a unique combination of non-dead zones,ultrafast measurement speed,high precision and accuracy,large ambiguity range,and only one single comb source.This system could offer a powerful solution for field measurements in practical applications in the future.
基金supported by the Office of Naval Research(Grant Nos.N00014-16-1-2094 and N00014-24-1-2547)the Lawrence Livermore National Laboratory(Grant No.B622827)the National Science Foundation.Y.-S.J.acknowledges support from KRISS(Grant Nos.25011026 and 25011211).
文摘Acoustic detection has many applications across science and technology from medicine to imaging and communications.However,most acoustic sensors have a common limitation in that the detection must be near the acoustic source.Alternatively,laser interferometry with picometer-scale motional displacement detection can rapidly and precisely measure sound-induced minute vibrations on remote surfaces.Here,we demonstrate the feasibility of sound detection up to 100 kHz at remote sites with≈60 m optical path length via laser homodyne interferometry.Based on our ultrastable hertz linewidth laser with 10-15 fractional stability,our laser interferometer achieves 0.5 pm/Hz1/2 displacement sensitivity near 10 kHz,bounded only by laser frequency noise over 10 kHz.Between 140 Hz and 15 kHz,we achieve a homodyne acoustic sensing sensitivity of subnanometer/Pascal across our conversational frequency overtones.The minimal sound pressure detectable over 60 m optical path length is≈2 mPa,with dynamic ranges over 100 dB.With the demonstrated standoff picometric distance metrology,we successfully detected and reconstructed musical scores of normal conversational volumes with high fidelity.The acoustic detection via this precision laser interferometer could be applied to selective area sound sensing for remote acoustic metrology,optomechanical vibrational motion sensing,and ultrasensitive optical microphones at the laser frequency noise limits.
基金support from the Lawrence Livermore National Laboratory(Grant No.B622827)the National Science Foundation(Grant Nos.1824568,1810506,1741707,and 1829071)the Office of Naval Research(Grant No.N00014-16-1-2094).
文摘Laser frequency microcombs provide a series of equidistant,coherent frequency markers across a broad spectrum,enabling advancements in laser spectroscopy,dense optical communications,precision distance metrology,and astronomy.Here,we design and fabricate silicon nitride,dispersion-managed microresonators that effectively suppress avoided-mode crossings and achieve close-to-zero averaged dispersion.Both the stochastic noise and mode-locking dynamics of the resonator are numerically and experimentally investigated.First,we experimentally demonstrate thermally stabilized microcomb formation in the microresonator across different mode-locked states,showing negligible center frequency shifts and a broad frequency bandwidth.Next,we characterize the femtosecond timing jitter of the microcombs,supported by precise metrology of the timing phase and relative intensity noise.For the single-soliton state,we report a relative intensity noise of−153.2 dB∕Hz,close to the shot-noise limit,and a quantum-noise–limited timing jitter power spectral density of 0.4 as 2∕Hz at a 100 kHz offset frequency,measured using a self-heterodyne linear interferometer.In addition,we achieve an integrated timing jitter of 1.7 fs±0.07 fs,measured from 10 kHz to 1 MHz.Measuring and understanding these fundamental noise parameters in high clock rate frequency microcombs is critical for advancing soliton physics and enabling new applications in precision metrology.
基金the National Key Research and Development Program of China(2022YFB3403404)the Youth Innovation Promotion Association,CAS(2022213)the National Natural Science Foundation of China(62127901 and 62305334).
文摘Null compensation interferometry is the primary testing method for the manufacture of ultra-high-precision aspheric mirrors.The crosstalk fringes generated by stray light in interferometry can affect accuracy and potentially prevent the testing from proceeding normally.Position errors include the decenter error,tilt error,and distance error.During the testing process,position errors will impact the testing accuracy and the crosstalk fringes generated by stray light.To determine the specific impact of position errors,we use the concept of Hindle shell testing of a convex aspheric mirror,and propose the simulation method of crosstalk fringes in null compensation interferometry.We also propose evaluation indices of crosstalk fringes in interferometry and simulate the influence of position errors on the crosstalk fringes.This work aims to help improve the design of compensation interferometry schemes,enhance the feasibility of the design,reduce engineering risks,and improve efficiency.
基金supported by the National Natural Science Foundation of China (Grant No. 12005106)support from the National Natural Science Foundation of China (Grant No. 11974189)+1 种基金support from the National Natural Science Foundation of China (Grant No. 12175106)the Postgraduate Research and Practice Innovation Program of Jiangsu Province (Grant No. JSCX23-0260)。
文摘We propose a quantum-enhanced metrological scheme utilizing unbalanced entangled coherent states(ECSs) generated by passing a coherent state and a coherent state superposition through an unbalanced beam splitter(BS). We identify the optimal phase sensitivity of this scheme by maximizing the quantum Fisher information(QFI) with respect to the BS transmission ratio. Our scheme outperforms the conventional scheme with a balanced BS, particularly in the presence of single-mode photon loss. Notably, our scheme retains quantum advantage in phase sensitivity in the limit of high photon intensity, where the balanced scheme offers no advantage over the classical strategy.
基金supported by the National Natural Science Foundation of China(Grants Nos.92476118 and 12275062).
文摘The Mach-Zehnder interferometer is a fundamental tool for measuring phase shifts between two light paths,serving as a crucial prototype for achieving high-precision measurements in various scientific and technological applications.In this study,we analyze different models for estimating the relative phase shift in a general two-arm Mach-Zehnder interferometer.We demonstrated that single-parameter estimation models can be reduced from the two-parameter estimation model by imposing appropriate constraints on the parameter space.To make quantum Fisher information of the single-parameter estimation models meaningful,the corresponding constraints must be guaranteed in the experiment implementation.Furthermore,we apply the quantum Fisher information approach to analyze the Mach-Zehnder interferometer with the an input state composed of a displaced squeezed vacuum state and a coherent state,providing insights into the precision limits of such configurations.
基金supported by the National Natural Science Foundation of China(Grant No.61705193)the Natural Science Foundation of Zhejiang Province(Grant No.LGG20F050002)the Jinhua Science and Technology Plan(Project No.2024-1-064).
文摘Laser interferometry with higher resolution,faster update rate,and larger dynamic range is highly anticipated in the exploration of physics frontiers,advanced manufacturing,and precision sensing.Real-time dispersive spectral interferometry(DSI)shows promise for high-speed precision measurements,whereas the resolution of subnanometers has not yet been achieved.We present a comprehensive theoretical framework to analyze the limitations of real-time DSI based on the signal-to-noise ratio and data volume.A real-time orthogonal polarization spectral interferometry technique is proposed,which utilizes a pair of interferograms with the pi-phase shift to effectively mitigate the phase noise embedded in real-time spectral envelopes,thereby enabling the precise measurements with subnanometer resolution at megahertz frame rates.The recorded time series data are processed through interpolation,segmentation,time–frequency mapping,and de-enveloping to regain the typical cosine-shaped spectral evolution,followed by a fitting-based phase retrieval method to extract the interference phase.The phase resolution of 1.1 mrad(0.91 as for time delay and 0.3 nm for distance)is obtained at the update rate of 22.2 MHz even under the detection bandwidth of 500 MHz,and can be further enhanced to 0.29 mrad(0.24 as for time delay)after 500 times averaging(∼0.5 MHz).Our approach is validated through periodic phase modulations and applied to measure the rapid damped oscillations of a piezo stage,yielding results consistent with those obtained from a commercial picometer interferometer.
基金supported by National Natural Science Foundation of China(No.52275540).
文摘Microsphere assisted microscopy(MAM)has been rapidly developed to meet the measurement needs of microstructures.MAM can be integrated with optical interference microscopy(OIM)to achieve high lateral resolution surface profile measurement.However,the microspheres introduce intricate phase changes,resulting in optical path asymmetry which is very challenging to compensate for.This limitation constrains the application of MAM in OIM.In this paper,simulation analysis reveals that the phase transmission of the microsphere is influenced by parameters such as microsphere diameter and its relative position to the sample.It is concluded that a unique compensation process must be adopted for each individual microsphere.Addressing this issue,we proposed a phase compensation algorithm based on the three-dimensional position control of the microsphere and integrated it into our combined system of MAM and white light interferometry(WLI),reducing the phase errors introduced by the microspheres while enhancing the lateral resolution of optical system.This approach improved the profile measurement accuracy,offering a perspective for optically measuring the surface profile of intricate microstructures.
基金supported by the Anhui Zhongchuang Energy New Energy Technology Co.,Ltd.,Entrusted Project.
文摘The semiconductor bridge(SCB)ignites through bridge film discharge,offering advantages such as low ignition energy,high safety,and compatibility with digital logic circuits.The study uses laser interferometry to investigate the gas dynamics of the bridge film after SCB plasma extinction.Interferometric images of the SCB film gas were obtained through a laser interferometry optical path.After the degradation model of digital image processing,clearer images were produced to facilitate analysis and calculation.The results show that the gas temperature at the center of the SCB film reaches a maximum of 1000 K,and the temperature rapidly decreases along the axial direction of the bridge surface to room temperature at 300 K.The maximum diffusion velocity of the plasma is 1.8 km/s.These findings provide critical insights for SCB design and ignition control.
基金supported by the National 863 Program of China (Grant No.2006A09A102-11)National Natural Science Foundation of China (Grant No.40730424)Important National Science & Technology Specific Projects (Grant No.2008ZX05023-005)
文摘In this paper,we image the subsurface reflectors by interferometric imaging using primary and downgoing first-order free-surface related multiple reflections in walkaway VSP data.By analyzing the stack fold distribution,we find that primary-direct interferometric imaging has a smaller image range,but its stack fold is higher near the well while ghostdirect interferometric imaging is the opposite.We try to solve this problem by the joint interferometric imaging of walkaway VSP data,combining primary-direct interferometric imaging with ghost-direct interferometric imaging.In this way,we can effectively widen the imaging range,simultaneously increase the fold（especially near the well）,suppress spurious interference,and improve the image SNR,so that we can get a more credible image.Test results on synthetic walkaway VSP data and field data show that joint interferometric imaging is very effective.
基金supported by the national project"Deep Exploration Technology and Experimentation"(SinoProbe-09-02)
文摘In order to suppress the airwave noise in marine controlled-source electromagnetic （CSEM） data, we propose a 3D deconvolution （3DD） interferometry method with a synthetic aperture source and obtain the relative anomaly coefficient （RAC） of the EM field reflection responses to show the degree for suppressing the airwave. We analyze the potential of the proposed method for suppressing the airwave, and compare the proposed method with traditional methods in their effectiveness. A method to select synthetic source length is derived and the effect of the water depth on RAC is examined via numerical simulations. The results suggest that 3DD interferometry method with a synthetic source can effectively suppress the airwave and enhance the potential of marine CSEM to hydrocarbon exploration.
