This paper presents a method to measure the in-plane displacement fields of curved surface by moire interferometry of partial coherent light.The method has the following advantages:simple optical system,no requirement...This paper presents a method to measure the in-plane displacement fields of curved surface by moire interferometry of partial coherent light.The method has the following advantages:simple optical system,no requirement on vibration isolation,high sensitivity,large measuring range,high contrast of inter ference fringes and availability to in-situ structural testing.The present paper also gives theoretical analysis of the method and the formulas of light intensity and displacement field,and introduces a replication technique to form a high frequency reflectance grating on the curved surface.The experiments achieved the measurement of the surface displacement field of a cylindrical shell—the simultaneous circumferential,axial and 45° displacement fields.The torsional test data for surface displacement of a circular bar agree well with the theoretical result.展开更多
Unidirectional imagers form images of input objects only in one direction,e.g.,from field-of-view(FOV)A to FOV B,while blocking the image formation in the reverse direction,from FOV B to FOV A.Here,we report unidirect...Unidirectional imagers form images of input objects only in one direction,e.g.,from field-of-view(FOV)A to FOV B,while blocking the image formation in the reverse direction,from FOV B to FOV A.Here,we report unidirectional imaging under spatially partially coherent light and demonstrate high-quality imaging only in the forward direction(A→B)with high power efficiency while distorting the image formation in the backward direction(B→A)along with low power efficiency.Our reciprocal design features a set of spatially engineered linear diffractive layers that are statistically optimized for partially coherent illumination with a given phase correlation length.Our analyses reveal that when illuminated by a partially coherent beam with a correlation length of≥∼1.5λ,whereλis the wavelength of light,diffractive unidirectional imagers achieve robust performance,exhibiting asymmetric imaging performance between the forward and backward directions—as desired.A partially coherent unidirectional imager designed with a smaller correlation length of<1.5λstill supports unidirectional image transmission but with a reduced figure of merit.These partially coherent diffractive unidirectional imagers are compact(axially spanning<75λ),polarization-independent,and compatible with various types of illumination sources,making them well-suited for applications in asymmetric visual information processing and communication.展开更多
Starting from the Rayleigh-Sommerfeld diffraction integral, this paper studies the spectral behavior in Young＇s experiment illuminated by nonparaxial partially coherent light and compares with the paraxial case, wher...Starting from the Rayleigh-Sommerfeld diffraction integral, this paper studies the spectral behavior in Young＇s experiment illuminated by nonparaxial partially coherent light and compares with the paraxial case, where the influence of nonparaxiality of partially coherent light on the spectral shifts and spectral switches is stressed. It is shown that there is a spectral shift in the nonparaxial case relative to the paraxial one and the critical position changes, at which the spectral switch occurs. The ratio of the waist width to the central wavelength ω0/λ0 and relative spatial correlation length △ affect the spectral difference. The smaller ω0/λ0 is, the larger the difference between the nonparaxial and paraxial results appears. The effect of relative spatial correlation length △ is relatively small.展开更多
Optical coherence is a fundamental property of light,playing a key role in understanding interference,propagation,and light-matter interactions for both classical and quantum light.Measuring the coherence properties o...Optical coherence is a fundamental property of light,playing a key role in understanding interference,propagation,and light-matter interactions for both classical and quantum light.Measuring the coherence properties of an optical field is crucial for a wide range of applications.However,despite many proposed measurement schemes,significant challenges still remain.In this work,we present a protocol to measure the full-dimensional coherence properties of a partially coherent beam.The method is based on tomographing the complex coherent modes of the partially coherent field within its coherence time.Once the complex coherent modes are reconstructed,all coherence properties including field correlation and its higher-order correlations(e.g.,intensity correlation)can be recovered for beams that are either spatially uniformly or non-uniformly correlated.We perform a proof-of-principle experiment to measure the complex field correlation and intensity correlation of a structured partially coherent beam synthesized by random modes.Additionally,we discuss the application of full-dimensional complex coherence function tomography in coherence-based multi-cipher information security.The robustness of our system in complex environments is also evaluated.展开更多
Optical encryption strategies utilizing fully coherent light have been widely explored but often face challenges such as speckle noise and beam instabilities.In this work,we introduce a novel protocol for multi-channe...Optical encryption strategies utilizing fully coherent light have been widely explored but often face challenges such as speckle noise and beam instabilities.In this work,we introduce a novel protocol for multi-channel optical information encoding and encryption using vectorial spatial coherence engineering of a partially coherent light beam.By characterizing the beam’s spatial coherence structure with a 2×2 coherence matrix,we demonstrate independent control over the three components of the coherence Stokes vector.This allows for three-channel optical information encoding and encryption,with applications in color image representation.Unlike existing methods based on fully coherent light modulations,our approach utilizes a two-point dependent coherence Stokes vector,proving resilient to random noise in experimental scenarios.Our findings provide a robust foundation for higher-dimensional optical encoding and encryption,addressing limitations associated with partially coherent light in complex environments.展开更多
Based on the propagation theory of partially coherent light in the space-frequency domain, the anomalous spectral behavior and spectral switches in the far field of partially coherent and polychromatic light diffracte...Based on the propagation theory of partially coherent light in the space-frequency domain, the anomalous spectral behavior and spectral switches in the far field of partially coherent and polychromatic light diffracted at an aperture are studied. It is shown that, as compared with spatially fully coherent and polychromatic light whose spectral anomalies are induced only by aperture diffraction, the spectral anomalies and spectral switches of partially coherent and polychromatic light depend on the aperture diffraction, spatial correlationβ and bandwidth of the original spectrum. Detailed numerical calculations are made to illustrate the behavior of spectral switches of partially coherent and polychromatic light, and the results for spatially fully coherent and polychromatic light are treated as a special case ofβ=1 and included in our theory.展开更多
In this Letter,we designed a random laser based on a nematic liquid crystal with titanium nitride nanoparticles,which has low spatial coherence,and its spatial coherence can be dynamically manipulated by the applied v...In this Letter,we designed a random laser based on a nematic liquid crystal with titanium nitride nanoparticles,which has low spatial coherence,and its spatial coherence can be dynamically manipulated by the applied voltage.In a scattering environment,the speckle effect can be effectively suppressed using the random laser as the light source,and the speckle degree is controlled by the applied voltage.Moreover,with the decrease of the spatial coherence of the random laser,the imaging edges become blurred.We provided a quantitative way to optimize the image quality between uniformity and edge sharpness while improving the signal-to-noise ratio.展开更多
基金The project supported by National Natural Science Foundation of China.
文摘This paper presents a method to measure the in-plane displacement fields of curved surface by moire interferometry of partial coherent light.The method has the following advantages:simple optical system,no requirement on vibration isolation,high sensitivity,large measuring range,high contrast of inter ference fringes and availability to in-situ structural testing.The present paper also gives theoretical analysis of the method and the formulas of light intensity and displacement field,and introduces a replication technique to form a high frequency reflectance grating on the curved surface.The experiments achieved the measurement of the surface displacement field of a cylindrical shell—the simultaneous circumferential,axial and 45° displacement fields.The torsional test data for surface displacement of a circular bar agree well with the theoretical result.
文摘Unidirectional imagers form images of input objects only in one direction,e.g.,from field-of-view(FOV)A to FOV B,while blocking the image formation in the reverse direction,from FOV B to FOV A.Here,we report unidirectional imaging under spatially partially coherent light and demonstrate high-quality imaging only in the forward direction(A→B)with high power efficiency while distorting the image formation in the backward direction(B→A)along with low power efficiency.Our reciprocal design features a set of spatially engineered linear diffractive layers that are statistically optimized for partially coherent illumination with a given phase correlation length.Our analyses reveal that when illuminated by a partially coherent beam with a correlation length of≥∼1.5λ,whereλis the wavelength of light,diffractive unidirectional imagers achieve robust performance,exhibiting asymmetric imaging performance between the forward and backward directions—as desired.A partially coherent unidirectional imager designed with a smaller correlation length of<1.5λstill supports unidirectional image transmission but with a reduced figure of merit.These partially coherent diffractive unidirectional imagers are compact(axially spanning<75λ),polarization-independent,and compatible with various types of illumination sources,making them well-suited for applications in asymmetric visual information processing and communication.
基金suported by the National Natural Science Foundation of China (Grant No 10574097)the Outstanding Young Researcher Foundation of Sichuan Province,China (Grant No 03ZQ026-061)+1 种基金the Applied and Basic Research Foundation of Sichuan Province,China (Grant No 05J Y029-102)the Natural Science Foundation of Yibin University,China (Grant No 2008B04)
文摘Starting from the Rayleigh-Sommerfeld diffraction integral, this paper studies the spectral behavior in Young＇s experiment illuminated by nonparaxial partially coherent light and compares with the paraxial case, where the influence of nonparaxiality of partially coherent light on the spectral shifts and spectral switches is stressed. It is shown that there is a spectral shift in the nonparaxial case relative to the paraxial one and the critical position changes, at which the spectral switch occurs. The ratio of the waist width to the central wavelength ω0/λ0 and relative spatial correlation length △ affect the spectral difference. The smaller ω0/λ0 is, the larger the difference between the nonparaxial and paraxial results appears. The effect of relative spatial correlation length △ is relatively small.
基金supports from the National Key Research and Development Project of China(2022YFA1404800)the National Natural Science Foundation of China(NSFC)(12404348,12347114,12274311,12274310,12192254,92250304,W2441005)+1 种基金the China Postdoctoral Science Foundation(2024M752311)the Jiangsu Funding Program for Excellent Postdoctoral Talent(2023ZB185).
文摘Optical coherence is a fundamental property of light,playing a key role in understanding interference,propagation,and light-matter interactions for both classical and quantum light.Measuring the coherence properties of an optical field is crucial for a wide range of applications.However,despite many proposed measurement schemes,significant challenges still remain.In this work,we present a protocol to measure the full-dimensional coherence properties of a partially coherent beam.The method is based on tomographing the complex coherent modes of the partially coherent field within its coherence time.Once the complex coherent modes are reconstructed,all coherence properties including field correlation and its higher-order correlations(e.g.,intensity correlation)can be recovered for beams that are either spatially uniformly or non-uniformly correlated.We perform a proof-of-principle experiment to measure the complex field correlation and intensity correlation of a structured partially coherent beam synthesized by random modes.Additionally,we discuss the application of full-dimensional complex coherence function tomography in coherence-based multi-cipher information security.The robustness of our system in complex environments is also evaluated.
基金National Key Research and Development Program of China(2022YFA1404800,2019YFA0705000)National Natural Science Foundation of China(11974218,12192254,12274310,12274311,92250304,12347114)Jiangsu Funding Program for Excellent Postdoctoral Talent(2023ZB185).
文摘Optical encryption strategies utilizing fully coherent light have been widely explored but often face challenges such as speckle noise and beam instabilities.In this work,we introduce a novel protocol for multi-channel optical information encoding and encryption using vectorial spatial coherence engineering of a partially coherent light beam.By characterizing the beam’s spatial coherence structure with a 2×2 coherence matrix,we demonstrate independent control over the three components of the coherence Stokes vector.This allows for three-channel optical information encoding and encryption,with applications in color image representation.Unlike existing methods based on fully coherent light modulations,our approach utilizes a two-point dependent coherence Stokes vector,proving resilient to random noise in experimental scenarios.Our findings provide a robust foundation for higher-dimensional optical encoding and encryption,addressing limitations associated with partially coherent light in complex environments.
文摘Based on the propagation theory of partially coherent light in the space-frequency domain, the anomalous spectral behavior and spectral switches in the far field of partially coherent and polychromatic light diffracted at an aperture are studied. It is shown that, as compared with spatially fully coherent and polychromatic light whose spectral anomalies are induced only by aperture diffraction, the spectral anomalies and spectral switches of partially coherent and polychromatic light depend on the aperture diffraction, spatial correlationβ and bandwidth of the original spectrum. Detailed numerical calculations are made to illustrate the behavior of spectral switches of partially coherent and polychromatic light, and the results for spatially fully coherent and polychromatic light are treated as a special case ofβ=1 and included in our theory.
基金supported by the National Key Research and Development Program of China(Nos.2022YFA1404800 and 2019YFA0705000)the National Natural Science Foundation of China(Nos.12104268,12474332,12192254,92250304,and 12304325)the Natural Science Foundation of Shandong Province(Nos.ZR2024QA064 and ZR2023MA073)。
文摘In this Letter,we designed a random laser based on a nematic liquid crystal with titanium nitride nanoparticles,which has low spatial coherence,and its spatial coherence can be dynamically manipulated by the applied voltage.In a scattering environment,the speckle effect can be effectively suppressed using the random laser as the light source,and the speckle degree is controlled by the applied voltage.Moreover,with the decrease of the spatial coherence of the random laser,the imaging edges become blurred.We provided a quantitative way to optimize the image quality between uniformity and edge sharpness while improving the signal-to-noise ratio.
