As a vectorial property,polarization encodes high-dimensional information of light.Polarization-based imaging can characterize detailed structural features of biomedical samples label-freely.However,compared with othe...As a vectorial property,polarization encodes high-dimensional information of light.Polarization-based imaging can characterize detailed structural features of biomedical samples label-freely.However,compared with other fundamental properties of light,such as intensity,wavelength and phase,polarization has a shorter application history in biomedicine,because of the requirement for both advanced polarization optical components and computational approaches,which can be achieved nowadays with the fast theoretical and hardware development.展开更多
Large-aperture optical components are of paramount importance in domains such as integrated circuits,photolithography,aerospace,and inertial confinement fusion.However,measuring their surface profiles relies predomina...Large-aperture optical components are of paramount importance in domains such as integrated circuits,photolithography,aerospace,and inertial confinement fusion.However,measuring their surface profiles relies predominantly on the phase-shifting approach,which involves collecting multiple interferograms and imposes stringent demands on environmental stability.These issues significantly hinder its ability to achieve real-time and dynamic high-precision measurements.Therefore,this study proposes a high-precision large-aperture single-frame interferometric surface profile measurement(LA-SFISPM)method based on deep learning and explores its capability to realize dynamic measurements with high accuracy.The interferogram is matched to the phase by training the data measured using the small aperture.The consistency of the surface features of the small and large apertures is enhanced via contrast learning and feature-distribution alignment.Hence,high-precision phase reconstruction of large-aperture optical components can be achieved without using a phase shifter.The experimental results show that for the tested mirror withΦ=820 mm,the surface profile obtained from LA-SFISPM is subtracted point-by-point from the ground truth,resulting in a maximum single-point error of 4.56 nm.Meanwhile,the peak-to-valley(PV)value is 0.0758λ,and the simple repeatability of root mean square(SR-RMS)value is 0.00025λ,which aligns well with the measured results obtained by ZYGO.In particular,a significant reduction in the measurement time(reduced by a factor of 48)is achieved compared with that of the traditional phase-shifting method.Our proposed method provides an efficient,rapid,and accurate method for obtaining the surface profiles of optical components with different diameters without employing a phase-shifting approach,which is highly desired in large-aperture interferometric measurement systems.展开更多
AIM： To analyze the clinical factors influencing the human vision corrections via the changing of ocular components of human eye in various applications; and to analyze refractive state via a new effective axial leng...AIM： To analyze the clinical factors influencing the human vision corrections via the changing of ocular components of human eye in various applications; and to analyze refractive state via a new effective axial length.METHODS： An effective eye model was introduced by the ocular components of human eye including refractive indexes, surface radius（r1, r2, R1, R2） and thickness（t, T） of the cornea and lens, the anterior chamber depth（S1） and the vitreous length（S2）. Gaussian optics was used to calculate the change rate of refractive error per unit amount of ocular components of a human eye（the rate function M）. A new criterion of myopia was presented via an effective axial length.RESULTS： For typical corneal and lens power of 42 and 21.9 diopters, the rate function Mj（j=1 to 6） were calculated for a 1% change of r1, r2, R1, R2, t, T（in diopters） M1=＋0.485, M2=-0.063, M3=＋0.053, M4=＋0.091, M5=＋0.012, and M6=-0.021 diopters. For 1.0 mm increase of S1 and S2, the rate functions were M7=＋1.35, and M8=-2.67 diopter/mm, respectively. These rate functions were used to analyze the clinical outcomes in various applications including laser in situ keratomileusis surgery, corneal cross linking procedure, femtosecond laser surgery and scleral ablation for accommodation.CONCLUSION： Using Gaussian optics, analytic formulas are presented for the change of refractive power due to various ocular parameter changes. These formulas provide useful clinical guidance in refractive surgery and other related procedures.展开更多
A novel time-domain ultra-fast pulse shaping approach for multi-TBaud serial optical communication signal (e.g. QPSK and 16-QAM) generation based on the first-order Born approximation in feasible all-fiber long-period...A novel time-domain ultra-fast pulse shaping approach for multi-TBaud serial optical communication signal (e.g. QPSK and 16-QAM) generation based on the first-order Born approximation in feasible all-fiber long-period gratings is proposed and numerically demonstrated.展开更多
Many theoretical studies have been developed to study the spectral response of a fiber Bragg grating (FBG) under non-uniform strain distribution along the length of FBG in recent years. However, almost no experiments ...Many theoretical studies have been developed to study the spectral response of a fiber Bragg grating (FBG) under non-uniform strain distribution along the length of FBG in recent years. However, almost no experiments were designed to obtain the evolution of the spectrum when a FBG is subjected to non-uniform strain. In this paper, the spectral responses of a FBG under non-uniform strain distributions are given and a numerical simulation based on the Runge-Kutta method is introduced to investigate the responses of the FBG under some typical non-uniform transverse strain fields, including both linear strain gradient and quadratic strain field. Experiment is carried out by using loads applied at different locations near the FBG. Good agreements between experimental results and numerical simulations are obtained.展开更多
In this paper,we present a novel oil level monitoring sensor based on string tilted fiber Bragg grating(TFBG).The measurement range and sensitivity of oil level monitoring can be modulated via changing the length and ...In this paper,we present a novel oil level monitoring sensor based on string tilted fiber Bragg grating(TFBG).The measurement range and sensitivity of oil level monitoring can be modulated via changing the length and number of string tilted fiber gratings.The transmission spectrum of string TFBGs immersed in oil changes obviously with the oil level variation.Experiments are conducted on three 2 cm-length serial TFBGs with the same tilted angle of 10o.A sensitivity of 3.28 dB/cm in the string TFBG sensor is achieved with good linearity by means of TFBG spectrum characteristic with peak-low value.The cladding mode transmission power and the amplitude of high order cladding mode resonance are nearly linear to the oil level variation.This kind of sensor is insensitive to temperature and attributed to be employed in extremely harsh environment oil monitoring.展开更多
Low-pressure air plasma cleaning is an effective method for removing organic contaminants on large-aperture optical components in situ in the inertial confinement fusion facility.Chemical reactions play a significant ...Low-pressure air plasma cleaning is an effective method for removing organic contaminants on large-aperture optical components in situ in the inertial confinement fusion facility.Chemical reactions play a significant role in plasma cleaning,which is a complex process involving abundant bond cleavage and species generation.In this work,experiments and reactive molecular dynamics simulations were carried out to unravel the reaction mechanism between the benchmark organic contaminants of dibutyl phthalate and air plasma.The optical emission spectroscopy was used to study the overall evolution behaviors of excited molecular species and radical signals from air plasma as a reference to simulations.Detailed reaction pathways were revealed and characterized,and specific intermediate radicals and products were analyzed during experiments and simulation.The reactive species in the air plasma,such as O,HO_(2)and O_(3)radicals,played a crucial role in cleaving organic molecular structures.Together,our findings provide an atomic-level understanding of complex reaction processes of low-pressure air plasma cleaning mechanisms and are essential for its application in industrial plasma cleaning.展开更多
With the rapid development of information and multi me dia technologies, the demand for the optical plastic aspheric elements used in o pto-electronic devices, camera, optical disc and projector lens etc. has been i n...With the rapid development of information and multi me dia technologies, the demand for the optical plastic aspheric elements used in o pto-electronic devices, camera, optical disc and projector lens etc. has been i ncreased rapidly in the recent years. The key technologies of fabrication of asp heric plastic lens are the design and manufacturing moulds, selection of proper injection moulding equipment, and optimization of injection moulding parameters etc. In this paper, the effect of injection pressure, moulding temperature, cool ing time and injection speed on the surface profile of the lenses during injecti on and holding process is investigated. Surface quality of plastic lenses is mea sured by Talysurf Texture Measuring System. The experimental results showed that the injection pressure and moulding temperature are important parameters compar ing to cooling time and injection speed. A bit change of injection pressure or m oulding temperature will affect the property of the surface profile. Either incr easing injection pressure or mould temperature can achieve less shrinkage. Other wise, a lower injection pressure will produce more shrinkage, more air traps and a lower mould temperature results greater warp and higher shrinkage. The dynami c process of injection for optical plastic lenses is simulated by 3D Moldflow pl astic Insight software (MPI). The MPI will help us to optimize injection mouldin g parameters.展开更多
Spatial modedivision multiplexing is emerging as a potential solution to further increasing optical fiber capacity and spectral efficiency. We report a dualmode, dualpolarization transmission method based on modeselec...Spatial modedivision multiplexing is emerging as a potential solution to further increasing optical fiber capacity and spectral efficiency. We report a dualmode, dualpolarization transmission method based on modeselective excitation and detection over a twomode fiber. In particular, we present 107 Gbit/s coherent optical OFDM （COOFDM） transmission over a 4.5 km twomode fiber using LP and LP. modes in which mode separation is performed optically.展开更多
A new method is presented to fabricate the triangular fiber Bragg grating(TFBG).The fabrication device is simple,only requires a single exposure and does not need to write complicated program.The transfer matrix metho...A new method is presented to fabricate the triangular fiber Bragg grating(TFBG).The fabrication device is simple,only requires a single exposure and does not need to write complicated program.The transfer matrix method is used to design the fiber Bragg grating,and the grating resonant wavelength and the grating reflectivity can be controlled in order to achieve the triangular spectrum.With different fiber tilt angles,the available bandwidth of TFBG,the linearity and the oblique gradient are also different.In the experiment,the angles 1°,1.5° and 2° are chosen.The results show that the best angle value is 1.5°,and the TFBG has a good linearity,greater gradient and wider available bandwidth.展开更多
This paper systematically investigated the impact mechanisms of proton irradiation,atomic oxygen irradiation and space debris collision,both individually and in combination,on the laser damage threshold and damage evo...This paper systematically investigated the impact mechanisms of proton irradiation,atomic oxygen irradiation and space debris collision,both individually and in combination,on the laser damage threshold and damage evolution characteristics of HfO_(2)/SiO_(2) triple-band high-reflection films and fused silica substrates using a simulated near-Earth space radiation experimental system.For the high-reflection film samples,the damage thresholds decreased by 15.38%,13.12% and 46.80% after proton,atomic oxygen and simulated space debris(penetration) irradiation,respectively.The coupling irradiation of the first two factors resulted in a decrease of 26.93%,while the combined effect of all the three factors led to a reduction of 63.19%.Similarly,the fused silica substrates exhibited the same pattern of laser damage performance degradation.Notably,the study employed high-precision fixed-point in situ measurement techniques to track in detail the microstructural changes,surface roughness and optical-thermal absorption intensity before and after proton and atomic oxygen irradiation at the same location,thus providing a more accurate and comprehensive analysis of the damage mechanisms.In addition,simulations were conducted to quantitatively analyze the transmission trajectories and concentration distribution lines of protons and atomic oxygen incident at specific angles into the target material.The research findings contribute to elucidating the laser damage performance degradation mechanism of transmissive elements in near-Earth space environments and provide technical support for the development of high-damage-threshold optical components resistant to space radiation.展开更多
Mid-frequency wavefront errors can be of the most importance for some optical components, but they're not explicitly covered by corresponding international standards such as ISO 10110. The testing methods for the ...Mid-frequency wavefront errors can be of the most importance for some optical components, but they're not explicitly covered by corresponding international standards such as ISO 10110. The testing methods for the errors also have a lot of aspects to be improved. This paper gives an overview of the specifications especially of PSD. NIF, developed by America, and XMM, developed by Europe, have both discovered some new testing methods.展开更多
Tailoring multiple degrees-of-freedom(DoFs)to achieve high-dimensional laser field is crucial for advancing optical technologies.While recent advancements have demonstrated the ability to manipulate a limited number o...Tailoring multiple degrees-of-freedom(DoFs)to achieve high-dimensional laser field is crucial for advancing optical technologies.While recent advancements have demonstrated the ability to manipulate a limited number of DoFs,most existing methods rely on bulky optical components or intricate systems that employ time-consuming iterative methods and,most critically,the on-demand tailoring of multiple DoFs simultaneously through a compact,single element—remains underexplored.In this study,we propose an intelligent hybrid strategy that enables the simultaneous and customizable manipulation of six DoFs:wave vector,initial phase,spatial mode,amplitude,orbital angular momentum(OAM)and spin angular momentum(SAM).Our approach advances in phase-only property,which facilitates tailoring strategy experimentally demonstrated on a compact metasurface.A fabricated sample is tailored to realize arbitrary manipulation across six DoFs,constructing a 288-dimensional space.Notably,since the OAM eigenstates constitute an infinite dimensional Hilbert space,this proposal can be further extended to even higher dimensions.Proof-of-principle experiments confirm the effectiveness in manipulation capability and dimensionality.We envision that this powerful tailoring ability offers immense potential for multifunctional photonic devices across both classical and quantum scenarios and such compactness extending the dimensional capabilities for integration on-chip requirements.展开更多
Light manipulation and control are essential in various contemporary technologies,and as these technologies evolve,the demand for miniaturized optical components increases.Planar-lens technologies,such as metasurfaces...Light manipulation and control are essential in various contemporary technologies,and as these technologies evolve,the demand for miniaturized optical components increases.Planar-lens technologies,such as metasurfaces and difractive optical elements,have gained attention in recent years for their potential to dramatically reduce the thickness of traditional refractive optical systems.However,their fabrication,particularly for visible wavelengths,involves complex and costly processes,such as high-resolution lithography and dry-etching,which has limited their availability.In this study,we present a simplifed method forfabricating visible Fresnel zone plate(FZP)planar lenses,a type of diffractive optical element,using an i-line stepper and a special photoresist(color resist)that only necessitates coating,exposure,and development,eliminating the need for etching or other post-processing steps.We fabricated visible FZp lens patterns using conventional photolithography equipment on 8-inch silica glass wafers,and demonstrated focusing of 550 nm light to a diameter of 1.1μm with a focusing efficiency of 7.2%.Numerical simulations showed excellent agreement with experimental results,confirming the high precision and designability of our method.Our lenses were also able to image objects with features down to 1.1μm,showcasing their potential for practical applications in imaging.Our method is a cost-effective,simple,and scalable solution for mass production of planar lenses and other optical components operating in the visible region.It enables the development of advanced,miniaturized optical systems to meet modern technology demand,making it a valuable contribution to optical component manufacturing.展开更多
Multi-spectral and multi-functional optical components play a crucial role in fields such as high-speed communications and optical sensing.However,the interaction between different spectra and matter varies significan...Multi-spectral and multi-functional optical components play a crucial role in fields such as high-speed communications and optical sensing.However,the interaction between different spectra and matter varies significantly,making it challenging to simultaneously achieve dynamic multi-spectral modulation capabilities.We designed a modulator based on a planar nested multiscale metasurface,incorporating silicon(Si)and perovskite as control materials,to modulate both microwave and terahertz(THz)ranges.展开更多
Large-area gratings play a crucial role in various engineering fields.However,traditional interference lithography is limited by the size of optical component apertures,making large-area fabrication a challenging task...Large-area gratings play a crucial role in various engineering fields.However,traditional interference lithography is limited by the size of optical component apertures,making large-area fabrication a challenging task.Here,a method for fabricating laser interference lithography pattern arrays with a global alignment reference strategy is proposed.This approach enables alignment of each area of the laser interference lithography pattern arrays,including phase,period,and tilt angle.Two reference gratings are utilized:one is detached from the substrate,while the other remains fixed to it.To achieve global alignment,the exposure area is adjusted by alternating between moving the beam and the substrate.In our experiment,a 3×3 regions grating array was fabricated,and the−1st-order diffraction wavefront measured by the Fizeau interferometer exhibited good continuity.This technique enables effective and efficient alignment with high accuracy across any region in an interference lithography pattern array on large substrates.It can also serve as a common technique for fabricating various types of periodic structures by rotating the substrate.展开更多
A distributed feedback diode laser （DFB-DL） based hygrometer combined with a long-path-length Herriot gas cell and waterless optical components was proposed and investigated. The main function of this sensor was to ...A distributed feedback diode laser （DFB-DL） based hygrometer combined with a long-path-length Herriot gas cell and waterless optical components was proposed and investigated. The main function of this sensor was to simultaneously improve the measurement reliability and resolution. A comparison test between a 10-cm normal transmission-type gas cell and a 3-m Herriot gas cell was carried out to demonstrate the improvement. Reliability improvement was achieved by influence suppression of water vapor inside optical components （WVOC） through combined action of the Herriot gas cell and waterless optical components. The influence of WVOC was suppressed from 726ppmv to 25ppmv using the Herriot gas cell. Moreover, combined with waterless optical components, the influence of WVOC was further suppressed to no more than 4ppmv. Resolution improvement from l l.7ppmv to 0.32ppmv was achieved mainly due to the application of the long-path-length Herriot gas cell. The results show that the proposed sensor has a good performance and considerable potential application in gas sensing, especially when probed gas possibly permeates into optical components.展开更多
文摘As a vectorial property,polarization encodes high-dimensional information of light.Polarization-based imaging can characterize detailed structural features of biomedical samples label-freely.However,compared with other fundamental properties of light,such as intensity,wavelength and phase,polarization has a shorter application history in biomedicine,because of the requirement for both advanced polarization optical components and computational approaches,which can be achieved nowadays with the fast theoretical and hardware development.
基金funded by the National Natural Science Foundation of China Instrumentation Program(52327806)Youth Fund of the National Nature Foundation of China(62405020)China Postdoctoral Science Foundation(2024M764131).
文摘Large-aperture optical components are of paramount importance in domains such as integrated circuits,photolithography,aerospace,and inertial confinement fusion.However,measuring their surface profiles relies predominantly on the phase-shifting approach,which involves collecting multiple interferograms and imposes stringent demands on environmental stability.These issues significantly hinder its ability to achieve real-time and dynamic high-precision measurements.Therefore,this study proposes a high-precision large-aperture single-frame interferometric surface profile measurement(LA-SFISPM)method based on deep learning and explores its capability to realize dynamic measurements with high accuracy.The interferogram is matched to the phase by training the data measured using the small aperture.The consistency of the surface features of the small and large apertures is enhanced via contrast learning and feature-distribution alignment.Hence,high-precision phase reconstruction of large-aperture optical components can be achieved without using a phase shifter.The experimental results show that for the tested mirror withΦ=820 mm,the surface profile obtained from LA-SFISPM is subtracted point-by-point from the ground truth,resulting in a maximum single-point error of 4.56 nm.Meanwhile,the peak-to-valley(PV)value is 0.0758λ,and the simple repeatability of root mean square(SR-RMS)value is 0.00025λ,which aligns well with the measured results obtained by ZYGO.In particular,a significant reduction in the measurement time(reduced by a factor of 48)is achieved compared with that of the traditional phase-shifting method.Our proposed method provides an efficient,rapid,and accurate method for obtaining the surface profiles of optical components with different diameters without employing a phase-shifting approach,which is highly desired in large-aperture interferometric measurement systems.
基金Supported by an Internal Research of New Vision Inc.,Taipei,Taiwan
文摘AIM： To analyze the clinical factors influencing the human vision corrections via the changing of ocular components of human eye in various applications; and to analyze refractive state via a new effective axial length.METHODS： An effective eye model was introduced by the ocular components of human eye including refractive indexes, surface radius（r1, r2, R1, R2） and thickness（t, T） of the cornea and lens, the anterior chamber depth（S1） and the vitreous length（S2）. Gaussian optics was used to calculate the change rate of refractive error per unit amount of ocular components of a human eye（the rate function M）. A new criterion of myopia was presented via an effective axial length.RESULTS： For typical corneal and lens power of 42 and 21.9 diopters, the rate function Mj（j=1 to 6） were calculated for a 1% change of r1, r2, R1, R2, t, T（in diopters） M1=＋0.485, M2=-0.063, M3=＋0.053, M4=＋0.091, M5=＋0.012, and M6=-0.021 diopters. For 1.0 mm increase of S1 and S2, the rate functions were M7=＋1.35, and M8=-2.67 diopter/mm, respectively. These rate functions were used to analyze the clinical outcomes in various applications including laser in situ keratomileusis surgery, corneal cross linking procedure, femtosecond laser surgery and scleral ablation for accommodation.CONCLUSION： Using Gaussian optics, analytic formulas are presented for the change of refractive power due to various ocular parameter changes. These formulas provide useful clinical guidance in refractive surgery and other related procedures.
基金supported in part by the Natural Sciences and En-gineering Research Council of Canada(NSERC),and le Fonds Qué-bécois de la Recherche sur la Nature et les Technologies(FQRNT).
文摘A novel time-domain ultra-fast pulse shaping approach for multi-TBaud serial optical communication signal (e.g. QPSK and 16-QAM) generation based on the first-order Born approximation in feasible all-fiber long-period gratings is proposed and numerically demonstrated.
基金supported by the National High Technology Research and Development Program of China (No.2007AA03Z117)the Key Program of National Natural Science Foundation of China (No.50830201)
文摘Many theoretical studies have been developed to study the spectral response of a fiber Bragg grating (FBG) under non-uniform strain distribution along the length of FBG in recent years. However, almost no experiments were designed to obtain the evolution of the spectrum when a FBG is subjected to non-uniform strain. In this paper, the spectral responses of a FBG under non-uniform strain distributions are given and a numerical simulation based on the Runge-Kutta method is introduced to investigate the responses of the FBG under some typical non-uniform transverse strain fields, including both linear strain gradient and quadratic strain field. Experiment is carried out by using loads applied at different locations near the FBG. Good agreements between experimental results and numerical simulations are obtained.
基金supported by the National Natural Science Foundation of China (No.51079080)
文摘In this paper,we present a novel oil level monitoring sensor based on string tilted fiber Bragg grating(TFBG).The measurement range and sensitivity of oil level monitoring can be modulated via changing the length and number of string tilted fiber gratings.The transmission spectrum of string TFBGs immersed in oil changes obviously with the oil level variation.Experiments are conducted on three 2 cm-length serial TFBGs with the same tilted angle of 10o.A sensitivity of 3.28 dB/cm in the string TFBG sensor is achieved with good linearity by means of TFBG spectrum characteristic with peak-low value.The cladding mode transmission power and the amplitude of high order cladding mode resonance are nearly linear to the oil level variation.This kind of sensor is insensitive to temperature and attributed to be employed in extremely harsh environment oil monitoring.
基金the Joint Funds of National Natural Science Foundation of China and China Academy of Engineering Physics(NSAF)(No.U2030109)National Natural Science Foundation of China(No.52075129)。
文摘Low-pressure air plasma cleaning is an effective method for removing organic contaminants on large-aperture optical components in situ in the inertial confinement fusion facility.Chemical reactions play a significant role in plasma cleaning,which is a complex process involving abundant bond cleavage and species generation.In this work,experiments and reactive molecular dynamics simulations were carried out to unravel the reaction mechanism between the benchmark organic contaminants of dibutyl phthalate and air plasma.The optical emission spectroscopy was used to study the overall evolution behaviors of excited molecular species and radical signals from air plasma as a reference to simulations.Detailed reaction pathways were revealed and characterized,and specific intermediate radicals and products were analyzed during experiments and simulation.The reactive species in the air plasma,such as O,HO_(2)and O_(3)radicals,played a crucial role in cleaving organic molecular structures.Together,our findings provide an atomic-level understanding of complex reaction processes of low-pressure air plasma cleaning mechanisms and are essential for its application in industrial plasma cleaning.
文摘With the rapid development of information and multi me dia technologies, the demand for the optical plastic aspheric elements used in o pto-electronic devices, camera, optical disc and projector lens etc. has been i ncreased rapidly in the recent years. The key technologies of fabrication of asp heric plastic lens are the design and manufacturing moulds, selection of proper injection moulding equipment, and optimization of injection moulding parameters etc. In this paper, the effect of injection pressure, moulding temperature, cool ing time and injection speed on the surface profile of the lenses during injecti on and holding process is investigated. Surface quality of plastic lenses is mea sured by Talysurf Texture Measuring System. The experimental results showed that the injection pressure and moulding temperature are important parameters compar ing to cooling time and injection speed. A bit change of injection pressure or m oulding temperature will affect the property of the surface profile. Either incr easing injection pressure or mould temperature can achieve less shrinkage. Other wise, a lower injection pressure will produce more shrinkage, more air traps and a lower mould temperature results greater warp and higher shrinkage. The dynami c process of injection for optical plastic lenses is simulated by 3D Moldflow pl astic Insight software (MPI). The MPI will help us to optimize injection mouldin g parameters.
文摘Spatial modedivision multiplexing is emerging as a potential solution to further increasing optical fiber capacity and spectral efficiency. We report a dualmode, dualpolarization transmission method based on modeselective excitation and detection over a twomode fiber. In particular, we present 107 Gbit/s coherent optical OFDM （COOFDM） transmission over a 4.5 km twomode fiber using LP and LP. modes in which mode separation is performed optically.
基金supported by the National Natural Science Foundation of China (Nos.60771008 and 60837002)the Natural Science Foundation of Beijing (No.4082024)+1 种基金the Ph.D. Programs Foundation of Ministry of Education of China (No.20090009110003)the Foundation for the Returning Scholars (No.2008890)
文摘A new method is presented to fabricate the triangular fiber Bragg grating(TFBG).The fabrication device is simple,only requires a single exposure and does not need to write complicated program.The transfer matrix method is used to design the fiber Bragg grating,and the grating resonant wavelength and the grating reflectivity can be controlled in order to achieve the triangular spectrum.With different fiber tilt angles,the available bandwidth of TFBG,the linearity and the oblique gradient are also different.In the experiment,the angles 1°,1.5° and 2° are chosen.The results show that the best angle value is 1.5°,and the TFBG has a good linearity,greater gradient and wider available bandwidth.
基金supported by the National Natural Science Foundation of China(No.61975153)。
文摘This paper systematically investigated the impact mechanisms of proton irradiation,atomic oxygen irradiation and space debris collision,both individually and in combination,on the laser damage threshold and damage evolution characteristics of HfO_(2)/SiO_(2) triple-band high-reflection films and fused silica substrates using a simulated near-Earth space radiation experimental system.For the high-reflection film samples,the damage thresholds decreased by 15.38%,13.12% and 46.80% after proton,atomic oxygen and simulated space debris(penetration) irradiation,respectively.The coupling irradiation of the first two factors resulted in a decrease of 26.93%,while the combined effect of all the three factors led to a reduction of 63.19%.Similarly,the fused silica substrates exhibited the same pattern of laser damage performance degradation.Notably,the study employed high-precision fixed-point in situ measurement techniques to track in detail the microstructural changes,surface roughness and optical-thermal absorption intensity before and after proton and atomic oxygen irradiation at the same location,thus providing a more accurate and comprehensive analysis of the damage mechanisms.In addition,simulations were conducted to quantitatively analyze the transmission trajectories and concentration distribution lines of protons and atomic oxygen incident at specific angles into the target material.The research findings contribute to elucidating the laser damage performance degradation mechanism of transmissive elements in near-Earth space environments and provide technical support for the development of high-damage-threshold optical components resistant to space radiation.
文摘Mid-frequency wavefront errors can be of the most importance for some optical components, but they're not explicitly covered by corresponding international standards such as ISO 10110. The testing methods for the errors also have a lot of aspects to be improved. This paper gives an overview of the specifications especially of PSD. NIF, developed by America, and XMM, developed by Europe, have both discovered some new testing methods.
基金supported by the National Key Research and Development Program of China(2022YFB3607700)National Natural Science Foundation of China(62350011,62375014)+1 种基金Beijing Natural Science Foundation(1232031)Special Fund for Basic Scientific Research of Central Universities of China(2024CX11002).
文摘Tailoring multiple degrees-of-freedom(DoFs)to achieve high-dimensional laser field is crucial for advancing optical technologies.While recent advancements have demonstrated the ability to manipulate a limited number of DoFs,most existing methods rely on bulky optical components or intricate systems that employ time-consuming iterative methods and,most critically,the on-demand tailoring of multiple DoFs simultaneously through a compact,single element—remains underexplored.In this study,we propose an intelligent hybrid strategy that enables the simultaneous and customizable manipulation of six DoFs:wave vector,initial phase,spatial mode,amplitude,orbital angular momentum(OAM)and spin angular momentum(SAM).Our approach advances in phase-only property,which facilitates tailoring strategy experimentally demonstrated on a compact metasurface.A fabricated sample is tailored to realize arbitrary manipulation across six DoFs,constructing a 288-dimensional space.Notably,since the OAM eigenstates constitute an infinite dimensional Hilbert space,this proposal can be further extended to even higher dimensions.Proof-of-principle experiments confirm the effectiveness in manipulation capability and dimensionality.We envision that this powerful tailoring ability offers immense potential for multifunctional photonic devices across both classical and quantum scenarios and such compactness extending the dimensional capabilities for integration on-chip requirements.
文摘Light manipulation and control are essential in various contemporary technologies,and as these technologies evolve,the demand for miniaturized optical components increases.Planar-lens technologies,such as metasurfaces and difractive optical elements,have gained attention in recent years for their potential to dramatically reduce the thickness of traditional refractive optical systems.However,their fabrication,particularly for visible wavelengths,involves complex and costly processes,such as high-resolution lithography and dry-etching,which has limited their availability.In this study,we present a simplifed method forfabricating visible Fresnel zone plate(FZP)planar lenses,a type of diffractive optical element,using an i-line stepper and a special photoresist(color resist)that only necessitates coating,exposure,and development,eliminating the need for etching or other post-processing steps.We fabricated visible FZp lens patterns using conventional photolithography equipment on 8-inch silica glass wafers,and demonstrated focusing of 550 nm light to a diameter of 1.1μm with a focusing efficiency of 7.2%.Numerical simulations showed excellent agreement with experimental results,confirming the high precision and designability of our method.Our lenses were also able to image objects with features down to 1.1μm,showcasing their potential for practical applications in imaging.Our method is a cost-effective,simple,and scalable solution for mass production of planar lenses and other optical components operating in the visible region.It enables the development of advanced,miniaturized optical systems to meet modern technology demand,making it a valuable contribution to optical component manufacturing.
基金National Natural Science Foundation of China(61975046,62375068)。
文摘Multi-spectral and multi-functional optical components play a crucial role in fields such as high-speed communications and optical sensing.However,the interaction between different spectra and matter varies significantly,making it challenging to simultaneously achieve dynamic multi-spectral modulation capabilities.We designed a modulator based on a planar nested multiscale metasurface,incorporating silicon(Si)and perovskite as control materials,to modulate both microwave and terahertz(THz)ranges.
基金supported by the National Natural Science Foundation of China(no.62275142)the Shenzhen Stable Supporting Program(no.WDZC20231124201906001).
文摘Large-area gratings play a crucial role in various engineering fields.However,traditional interference lithography is limited by the size of optical component apertures,making large-area fabrication a challenging task.Here,a method for fabricating laser interference lithography pattern arrays with a global alignment reference strategy is proposed.This approach enables alignment of each area of the laser interference lithography pattern arrays,including phase,period,and tilt angle.Two reference gratings are utilized:one is detached from the substrate,while the other remains fixed to it.To achieve global alignment,the exposure area is adjusted by alternating between moving the beam and the substrate.In our experiment,a 3×3 regions grating array was fabricated,and the−1st-order diffraction wavefront measured by the Fizeau interferometer exhibited good continuity.This technique enables effective and efficient alignment with high accuracy across any region in an interference lithography pattern array on large substrates.It can also serve as a common technique for fabricating various types of periodic structures by rotating the substrate.
基金This work was supported by the National Natural Science Foundation of China （60977058 ＆ 61475085）, the Science and Technology Development Project of Shandong Province （2014GGX101007）, and the Fundamental Research Funds of Shandong University （2014YQ011）.
文摘A distributed feedback diode laser （DFB-DL） based hygrometer combined with a long-path-length Herriot gas cell and waterless optical components was proposed and investigated. The main function of this sensor was to simultaneously improve the measurement reliability and resolution. A comparison test between a 10-cm normal transmission-type gas cell and a 3-m Herriot gas cell was carried out to demonstrate the improvement. Reliability improvement was achieved by influence suppression of water vapor inside optical components （WVOC） through combined action of the Herriot gas cell and waterless optical components. The influence of WVOC was suppressed from 726ppmv to 25ppmv using the Herriot gas cell. Moreover, combined with waterless optical components, the influence of WVOC was further suppressed to no more than 4ppmv. Resolution improvement from l l.7ppmv to 0.32ppmv was achieved mainly due to the application of the long-path-length Herriot gas cell. The results show that the proposed sensor has a good performance and considerable potential application in gas sensing, especially when probed gas possibly permeates into optical components.
