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
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
The field entropy of the system with two moving atoms interacting with the coherent state is investigated by means of the full quantum theory. Under the different initial states with two atoms, the influences of the l...The field entropy of the system with two moving atoms interacting with the coherent state is investigated by means of the full quantum theory. Under the different initial states with two atoms, the influences of the light field intensity and the atomic motion on the field entropy are discussed. The results indicate that the motion of the atoms leads to strict periodicity in the field entropy evolution. When the two atoms are in the Bell state ｜β11〉 initially, the system is in a completely disentangled state. For the atoms initially at other Bell states, the field periodically entangles with the atoms.展开更多
This paper presents a comprehensive technical overview of the Linac Coherent Light Source II(LCLS-II)photoinjector laser system,its first and foremost component.The LCLS-II photoinjector laser system serves as an upgr...This paper presents a comprehensive technical overview of the Linac Coherent Light Source II(LCLS-II)photoinjector laser system,its first and foremost component.The LCLS-II photoinjector laser system serves as an upgrade to the original LCLS at SLAC National Accelerator Laboratory.This advanced laser system generates high-quality laser beams for the LCLS-II,contributing to the instrument's unprecedented brightness,precision and flexibility.Our discussion extends to the various subsystems that comprise the photoinjector,including the photocathode laser,laser heater and beam transport systems.Lastly,we draw attention to the ongoing research and development infrastructure underway to enhance the functionality and efficiency of the LCLS-II,and similar X-ray free-electron laser facilities around the world,thereby contributing to the future of laser technology and its applications.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
The spectral behavior of polychromatic spatially fully coherent light diffracted by an annular aperture in the far field is studied. It is shown that the spectrum in the far field is generally different from that at t...The spectral behavior of polychromatic spatially fully coherent light diffracted by an annular aperture in the far field is studied. It is shown that the spectrum in the far field is generally different from that at the aperture, i.e., the spectrum in the far field is proportional to the spectrum at the aperture and a spectral modifier, which depends on the central obstruction ratio ε and diffraction angle θ. Detailed numerical calculation results indicate that significant spectral changes take place in the vicinity of zeros of the Airy pattern. It is found that at the critical diffraction angle θc, the spectrum is split into two lines, while at a diffraction angle a little smaller than θc, the spectrum is red-shifted, and at a diffraction angle a little larger than θc, the spectrum is blue-shifted. The influence of the central obstruction ratio on the spectral anomalies is presented.展开更多
We present a computer simulation model for the Hanbury Brown-Twiss experiment that is entirely particle-based and reproduces the results of wave theory. Themodel is solely based on experimental facts, satisfies Einst...We present a computer simulation model for the Hanbury Brown-Twiss experiment that is entirely particle-based and reproduces the results of wave theory. Themodel is solely based on experimental facts, satisfies Einstein’s criterion of local causality and does not require knowledge of the solution of a wave equation. The simulationmodel is fully consistent with earlier work and provides another demonstration thatit is possible to give a particle-only description of wave phenomena, rendering theconcept of wave-particle duality superfluous.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
Coherent broadband light generation has attracted massive attention due to its numerous applications ranging from metrology,sensing,and imaging to communication.In general,spectral broadening is realized via third-ord...Coherent broadband light generation has attracted massive attention due to its numerous applications ranging from metrology,sensing,and imaging to communication.In general,spectral broadening is realized via third-order and higher-order nonlinear optical processes(e.g.,self-phase modulation,Raman transition,four-wave mixing,multiwave mixing),which are typically weak and thus require a long interaction length and the phase matching condition to enhance the efficient nonlinear light-matter interaction for broad-spectrum generation.Here,for the first time,we report octave-spanning coherent light generation at the nanometer scale enabled by a phase-matching-free frequency down-conversion process.Up to octave-spanning coherent light generation with a-4odB spectral width covering from~565 to 1906 nm is demonstrated in discreate manner via difference-frequency generation,a second-order nonlinear process in galium selenide and niobium oxide diodide crystals at the 100-nanometer scale.Compared with conventional coherent broadband light sources based on bulk materials,our demonstration is~5 orders of magnitude thinner and requires~3 orders of magnitude lower excitation power.Our results open a new way to possibly create compact,versatile and integrated ultra-broadband light sources.展开更多
In this review,we describe our research on the development of the 13.5 nm coherent microscope using high-order harmonics for the mask inspection of extreme ultraviolet(EUV)lithography.EUV lithography is a game-changin...In this review,we describe our research on the development of the 13.5 nm coherent microscope using high-order harmonics for the mask inspection of extreme ultraviolet(EUV)lithography.EUV lithography is a game-changing piece of technology for high-volume manufacturing of commercial semiconductors.Many top manufacturers apply EUV technology for fabricating the most critical layers of 7 nm chips.Fabrication and inspection of defect-free masks,however,still remain critical issues in EUV technology.Thus,in our pursuit for a resolution,we have developed the coherent EUV scatterometry microscope(CSM)system with a synchrotron radiation(SR)source to establish the actinic metrology,along with inspection algorithms.The intensity and phase images of patterned EUV masks were reconstructed from diffraction patterns using ptychography algorithms.To expedite the practical application of the CSM,we have also developed a standalone CSM,based on high-order harmonic generation,as an alternative to the SR-CSM.Since the application of a coherent 13.5 nm harmonic enabled the production of a high contrast diffraction pattern,diffraction patterns of sub-100 ns size defects in a 2D periodic pattern mask could be observed.Reconstruction of intensity and phase images from diffraction patterns were also performed for a periodic line-and-space structure,an aperiodic angle edge structure,as well as a cross pattern in an EUV mask.展开更多
Free-electron light sources feature extraordinary luminosity,directionality,and coherence,which has enabled significant scientific progress in fields including physics,chemistry,and biology.The next generation of ligh...Free-electron light sources feature extraordinary luminosity,directionality,and coherence,which has enabled significant scientific progress in fields including physics,chemistry,and biology.The next generation of light sources has aimed at compact radiation sources driven by free electrons,with the advantages of reduction in both space and cost.With the rapid development of ultra-intense and ultrashort lasers,great effort has been devoted to the quest for compact free-electron lasers(FELs).This review focuses on the current efforts and advancements in the development of compact FELs,with a particular emphasis on two notable paths:the development of compact accelerators and the construction of micro undulators based on innovative materials/structures or optical modulation of electrons.In addition,the physical essence of inverse Compton scattering is discussed,which offers remarkable capability to develop an optical undulator with a spatial period that matches the optical wavelength.Recent scientific developments and future directions for miniaturized and integrated free-electron coherent light sources are also reviewed.In the future,the prospect of generating ultrashort electron pulses will provide fascinating means of producing superradiant radiation,promising high brilliance and coherence even on a micro scale using optical micro undulators.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
We use quantum field entropy to measure the degree of entanglement for a coherent state light field interacting with two atoms that are initially in an arbitrary two-qubit state. The influence of different mean photon...We use quantum field entropy to measure the degree of entanglement for a coherent state light field interacting with two atoms that are initially in an arbitrary two-qubit state. The influence of different mean photon number of the coherent field on the entropy of the field is discussed in detail when the two atoms are initially in one superposition state of the Bell states. The results show that the mean photon number of the light field can regulate the quantum entanglement between the atoms and light field.展开更多
The damage characteristics of fused silica were investigated under low-temporal coherence light(LTCL).It was found that the laser-induced damage threshold(LIDT)of fused silica for the LTCL was lower than that of the s...The damage characteristics of fused silica were investigated under low-temporal coherence light(LTCL).It was found that the laser-induced damage threshold(LIDT)of fused silica for the LTCL was lower than that of the single longitudinal mode pulse laser,and for the LTCLs,the LIDTs decrease with the increasing of laser bandwidth,which is not consistent with the temporal spike intensity.This is due to the nonlinear self-focusing effect and multi-pulse accumulation effect.The specific reasons were analyzed based on theoretical simulation and experimental study.This research work is helpful and of great significance for the construction of high-power LTCL devices.展开更多
Squeezed state of light explores a new era in noiseless communication and data processing recently breaking the quantum limit of noise. We propose a new mechanism of modulating an amplitude-squeezed signal with the in...Squeezed state of light explores a new era in noiseless communication and data processing recently breaking the quantum limit of noise. We propose a new mechanism of modulating an amplitude-squeezed signal with the instantaneous intensity variation of a coherent signal. The modulating signal is a coherent light where the amplitude-squeezed light takes the role of a carrier signal.展开更多
Coherence preserves phase consistency between wavefields,enabling accurate recording and reconstruction in holography.Although recent advances in computational optics have realized holographic data acquisition using i...Coherence preserves phase consistency between wavefields,enabling accurate recording and reconstruction in holography.Although recent advances in computational optics have realized holographic data acquisition using incoherent light by computationally retrieving information,optical reconstruction still requires partially coherent light sources.We demonstrate a hologram that reconstructs 3-dimensional distribution utilizing incoherence.By decomposing incoherent light into infinitesimal coherent lights and calculating their propagations,the incoherent sum is optimized to resemble the desired 3-dimensional scene,whereas individual coherent lights reconstruct completely different intensities.Incoherence provides high image quality and a wide eyebox,with the reconstructed intensity remaining shift-invariant under pupil displacement,allowing a 1000-fold expansion of the eyebox.We confirm the shift-invariance through a proof-of-concept experiment and demonstrate real-time synthesis of incoherent holograms using a neural network,significantly reducing computational costs.Our method could inspire new approaches in photonics using incoherent light and be practically adopted in holographic displays.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
In Brillouin distributed optical fiber sensor, using optical coherent detection to detect Brillouin scattering optical signal is a good method, but there exists the polarization correlated detection problem. A novel d...In Brillouin distributed optical fiber sensor, using optical coherent detection to detect Brillouin scattering optical signal is a good method, but there exists the polarization correlated detection problem. A novel detecting scheme is presented and demonstrated experimentally, which adopts orthogonal polarization diversity reception to resolve the polarization correlated detection problem. A laser is used as pump and reference light sources, a microwave electric-optical modulator (EOM) is adopted to produce frequency shift reference light, a polarization controller is used to control the polarization of the reference light which is changed into two orthogonal polarization for two adjacent acquisition periods. The Brillouin scattering light is coherently detected with the reference light, and the Brillouin scattering optical signal is taken out based on Brillouin frequency shift. After electronic processing, better Brillouin distributed sensing signal is obtained. A 25-km Brillouin distributed optical fi展开更多
Based on the Rytov approximation and the cross-spectral density approximation for the mutual coherence function of the partially coherent field, the propagation properties of the partially coherent beams with optical ...Based on the Rytov approximation and the cross-spectral density approximation for the mutual coherence function of the partially coherent field, the propagation properties of the partially coherent beams with optical vortices in turbulent atmosphere are discussed. The average intensity and the mutual coherence function of the partially coherent vortex beams propagation in weak turbulent atmosphere are obtained. It is shown that the vortex structure of the average cross-spectral density of partially coherent beams has the same helicoidally shape as that of the phase of the fully coherent Laguerre-Gauss beams in free space and the relative intensity of the beam is degraded by optical vortex.展开更多
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.
基金supported by the National Natural Science Foundation of Chinathe Nataral Science Foundation of Inner Mongolia of Chinathe Science Fund of Universiey in Inner Mongolia of China
文摘The field entropy of the system with two moving atoms interacting with the coherent state is investigated by means of the full quantum theory. Under the different initial states with two atoms, the influences of the light field intensity and the atomic motion on the field entropy are discussed. The results indicate that the motion of the atoms leads to strict periodicity in the field entropy evolution. When the two atoms are in the Bell state ｜β11〉 initially, the system is in a completely disentangled state. For the atoms initially at other Bell states, the field periodically entangles with the atoms.
基金the support from the SLAC National Accelerator Laboratory,the U.S.Department of Energy(DOE),the Office of Science,Office of Basic Energy Sciences under Contract No.DE-AC02-76SF00515,No.DE-SC0022559,No.DE-SC0022464,No.DE-FOA0002859the National Science Foundation under Contract No.2231334the U.S.Department of Defense under a National Defense Science and Engineering Fellowship。
文摘This paper presents a comprehensive technical overview of the Linac Coherent Light Source II(LCLS-II)photoinjector laser system,its first and foremost component.The LCLS-II photoinjector laser system serves as an upgrade to the original LCLS at SLAC National Accelerator Laboratory.This advanced laser system generates high-quality laser beams for the LCLS-II,contributing to the instrument's unprecedented brightness,precision and flexibility.Our discussion extends to the various subsystems that comprise the photoinjector,including the photocathode laser,laser heater and beam transport systems.Lastly,we draw attention to the ongoing research and development infrastructure underway to enhance the functionality and efficiency of the LCLS-II,and similar X-ray free-electron laser facilities around the world,thereby contributing to the future of laser technology and its applications.
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.
基金This research was supported by the National Natural Science Foundation of China (No. 60477041).
文摘The spectral behavior of polychromatic spatially fully coherent light diffracted by an annular aperture in the far field is studied. It is shown that the spectrum in the far field is generally different from that at the aperture, i.e., the spectrum in the far field is proportional to the spectrum at the aperture and a spectral modifier, which depends on the central obstruction ratio ε and diffraction angle θ. Detailed numerical calculation results indicate that significant spectral changes take place in the vicinity of zeros of the Airy pattern. It is found that at the critical diffraction angle θc, the spectrum is split into two lines, while at a diffraction angle a little smaller than θc, the spectrum is red-shifted, and at a diffraction angle a little larger than θc, the spectrum is blue-shifted. The influence of the central obstruction ratio on the spectral anomalies is presented.
文摘We present a computer simulation model for the Hanbury Brown-Twiss experiment that is entirely particle-based and reproduces the results of wave theory. Themodel is solely based on experimental facts, satisfies Einstein’s criterion of local causality and does not require knowledge of the solution of a wave equation. The simulationmodel is fully consistent with earlier work and provides another demonstration thatit is possible to give a particle-only description of wave phenomena, rendering theconcept of wave-particle duality superfluous.
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support from the Academy of Finland(Grant Nos.314810,333982,336144 and 336818)the Academy of Finland Flagship Program(Grant No.320167,PREIN)+1 种基金the European Union's Horizon 2020 research and innovation program(Grant No.820423,S2QUIP)the EU H2020-MSCA-RISE-872049(IPN-Bio)and ERC(Grant No.834742).
文摘Coherent broadband light generation has attracted massive attention due to its numerous applications ranging from metrology,sensing,and imaging to communication.In general,spectral broadening is realized via third-order and higher-order nonlinear optical processes(e.g.,self-phase modulation,Raman transition,four-wave mixing,multiwave mixing),which are typically weak and thus require a long interaction length and the phase matching condition to enhance the efficient nonlinear light-matter interaction for broad-spectrum generation.Here,for the first time,we report octave-spanning coherent light generation at the nanometer scale enabled by a phase-matching-free frequency down-conversion process.Up to octave-spanning coherent light generation with a-4odB spectral width covering from~565 to 1906 nm is demonstrated in discreate manner via difference-frequency generation,a second-order nonlinear process in galium selenide and niobium oxide diodide crystals at the 100-nanometer scale.Compared with conventional coherent broadband light sources based on bulk materials,our demonstration is~5 orders of magnitude thinner and requires~3 orders of magnitude lower excitation power.Our results open a new way to possibly create compact,versatile and integrated ultra-broadband light sources.
文摘In this review,we describe our research on the development of the 13.5 nm coherent microscope using high-order harmonics for the mask inspection of extreme ultraviolet(EUV)lithography.EUV lithography is a game-changing piece of technology for high-volume manufacturing of commercial semiconductors.Many top manufacturers apply EUV technology for fabricating the most critical layers of 7 nm chips.Fabrication and inspection of defect-free masks,however,still remain critical issues in EUV technology.Thus,in our pursuit for a resolution,we have developed the coherent EUV scatterometry microscope(CSM)system with a synchrotron radiation(SR)source to establish the actinic metrology,along with inspection algorithms.The intensity and phase images of patterned EUV masks were reconstructed from diffraction patterns using ptychography algorithms.To expedite the practical application of the CSM,we have also developed a standalone CSM,based on high-order harmonic generation,as an alternative to the SR-CSM.Since the application of a coherent 13.5 nm harmonic enabled the production of a high contrast diffraction pattern,diffraction patterns of sub-100 ns size defects in a 2D periodic pattern mask could be observed.Reconstruction of intensity and phase images from diffraction patterns were also performed for a periodic line-and-space structure,an aperiodic angle edge structure,as well as a cross pattern in an EUV mask.
基金supported by the Shanghai Pilot Program for Basic Research-Chinese Academy of Sciences,ShanghaiBranchNational Natural Science Foundation of China(Nos.12104471,U226720057,and 62105346)+3 种基金Key Research Program of Frontier Sciences,Chinese Academy of SciencesYouth Innovation Promotion Association of Chinese Academy of SciencesCAS Project for Young Scientists in Basic Research(No.YSBRO60)Shanghai Sailing Program(No.21YF1453900).
文摘Free-electron light sources feature extraordinary luminosity,directionality,and coherence,which has enabled significant scientific progress in fields including physics,chemistry,and biology.The next generation of light sources has aimed at compact radiation sources driven by free electrons,with the advantages of reduction in both space and cost.With the rapid development of ultra-intense and ultrashort lasers,great effort has been devoted to the quest for compact free-electron lasers(FELs).This review focuses on the current efforts and advancements in the development of compact FELs,with a particular emphasis on two notable paths:the development of compact accelerators and the construction of micro undulators based on innovative materials/structures or optical modulation of electrons.In addition,the physical essence of inverse Compton scattering is discussed,which offers remarkable capability to develop an optical undulator with a spatial period that matches the optical wavelength.Recent scientific developments and future directions for miniaturized and integrated free-electron coherent light sources are also reviewed.In the future,the prospect of generating ultrashort electron pulses will provide fascinating means of producing superradiant radiation,promising high brilliance and coherence even on a micro scale using optical micro undulators.
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Project supported by the National Natural Science Foundation of China(Grant No.11404108)
文摘We use quantum field entropy to measure the degree of entanglement for a coherent state light field interacting with two atoms that are initially in an arbitrary two-qubit state. The influence of different mean photon number of the coherent field on the entropy of the field is discussed in detail when the two atoms are initially in one superposition state of the Bell states. The results show that the mean photon number of the light field can regulate the quantum entanglement between the atoms and light field.
基金supported by National Natural Science Foundation of China(No.12074353)。
文摘The damage characteristics of fused silica were investigated under low-temporal coherence light(LTCL).It was found that the laser-induced damage threshold(LIDT)of fused silica for the LTCL was lower than that of the single longitudinal mode pulse laser,and for the LTCLs,the LIDTs decrease with the increasing of laser bandwidth,which is not consistent with the temporal spike intensity.This is due to the nonlinear self-focusing effect and multi-pulse accumulation effect.The specific reasons were analyzed based on theoretical simulation and experimental study.This research work is helpful and of great significance for the construction of high-power LTCL devices.
文摘Squeezed state of light explores a new era in noiseless communication and data processing recently breaking the quantum limit of noise. We propose a new mechanism of modulating an amplitude-squeezed signal with the instantaneous intensity variation of a coherent signal. The modulating signal is a coherent light where the amplitude-squeezed light takes the role of a carrier signal.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(No.RS-2023-00245184 and RS-2024-00341142)。
文摘Coherence preserves phase consistency between wavefields,enabling accurate recording and reconstruction in holography.Although recent advances in computational optics have realized holographic data acquisition using incoherent light by computationally retrieving information,optical reconstruction still requires partially coherent light sources.We demonstrate a hologram that reconstructs 3-dimensional distribution utilizing incoherence.By decomposing incoherent light into infinitesimal coherent lights and calculating their propagations,the incoherent sum is optimized to resemble the desired 3-dimensional scene,whereas individual coherent lights reconstruct completely different intensities.Incoherence provides high image quality and a wide eyebox,with the reconstructed intensity remaining shift-invariant under pupil displacement,allowing a 1000-fold expansion of the eyebox.We confirm the shift-invariance through a proof-of-concept experiment and demonstrate real-time synthesis of incoherent holograms using a neural network,significantly reducing computational costs.Our method could inspire new approaches in photonics using incoherent light and be practically adopted in holographic displays.
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.
基金This work was supported by the Zhejiang Provincial Natural Science Foundation of China under Grant No. 603127.
文摘In Brillouin distributed optical fiber sensor, using optical coherent detection to detect Brillouin scattering optical signal is a good method, but there exists the polarization correlated detection problem. A novel detecting scheme is presented and demonstrated experimentally, which adopts orthogonal polarization diversity reception to resolve the polarization correlated detection problem. A laser is used as pump and reference light sources, a microwave electric-optical modulator (EOM) is adopted to produce frequency shift reference light, a polarization controller is used to control the polarization of the reference light which is changed into two orthogonal polarization for two adjacent acquisition periods. The Brillouin scattering light is coherently detected with the reference light, and the Brillouin scattering optical signal is taken out based on Brillouin frequency shift. After electronic processing, better Brillouin distributed sensing signal is obtained. A 25-km Brillouin distributed optical fi
基金This work was supported by the Key Project of Chi-nese Ministry of Education under Grant No. 01091.
文摘Based on the Rytov approximation and the cross-spectral density approximation for the mutual coherence function of the partially coherent field, the propagation properties of the partially coherent beams with optical vortices in turbulent atmosphere are discussed. The average intensity and the mutual coherence function of the partially coherent vortex beams propagation in weak turbulent atmosphere are obtained. It is shown that the vortex structure of the average cross-spectral density of partially coherent beams has the same helicoidally shape as that of the phase of the fully coherent Laguerre-Gauss beams in free space and the relative intensity of the beam is degraded by optical vortex.
