Photoinduced birefringence is investigated in a new amorphous copolymer containing azobenzene groups. The levels of birefringence signal are found to depend on the polarization angle between the pump beam and the prob...Photoinduced birefringence is investigated in a new amorphous copolymer containing azobenzene groups. The levels of birefringence signal are found to depend on the polarization angle between the pump beam and the probe beam, and on the ellipticity of the pump beam. Both the growth and decay processes of the birefringence signal can be described by known biexponential equations. The rate constants and the amplitudes associated with the growth process of the photoinduced birefringence are observed to display a linear dependence with the pump beam intensity. A new dynamic model of the photoinduced birefringence is presented taking into account the contributions of both the trans and cis isomers ofazobenzene groups and the local polymer segments. The numerical treatment of this model shows good agreement with the experimental data in the whole writing-erasing processes of the photoinduced birefringence conducted in our polymer samples.展开更多
A new type of V-shaped photonic crystal fiber with elliptical air-holes is proposed to realize simultaneous high birefringence and nonlinearity at a wavelength of 1.55μm.The full vector finite element method was adop...A new type of V-shaped photonic crystal fiber with elliptical air-holes is proposed to realize simultaneous high birefringence and nonlinearity at a wavelength of 1.55μm.The full vector finite element method was adopted to investigate its characteristics,including birefringence,nonlinearity,and dispersion.The PCF exhibited a very high birefringence of 2.89×10^(-2) and very high nonlinear coefficient of 102.69 W^(-1)·km^(-1).In particular,there were two zero-dispersion wavelengths(ZDWs)in the visible(X:640-720 nm and Y:730-760 nm)and near-infrared regions(X:1050-1606 nm and Y:850-1500 nm).The combination of high birefringence and nonlinearity allowed the PCF to maintain the polarization state and generate a broadband super continuum,with potential applications in nonlinear optics.展开更多
The formulas which are suitable to birefringent medium with symmetric plane are derived bymeans of phase retard integration.We have adopted this concept to the axisymmetric problems and deducedsome useful formulas for...The formulas which are suitable to birefringent medium with symmetric plane are derived bymeans of phase retard integration.We have adopted this concept to the axisymmetric problems and deducedsome useful formulas for these cases.As a practical application,the strain rate analysis of flow in adiverging or a converging vessel is illustrated at the end of this paper.展开更多
It is demonstrated that the form birefringence related to the so-called nanogratings is quantitatively correlated to the porosity-filling factor of these nanostructures. We reveal that matters surrounding the nanopore...It is demonstrated that the form birefringence related to the so-called nanogratings is quantitatively correlated to the porosity-filling factor of these nanostructures. We reveal that matters surrounding the nanopores exhibit significant refractive index decrease which is likely due to the fictive temperature increase and/or the presence of a significant amount of interstitial O2. The control of the porosity was achieved by adjusting the laser pulse energy and the number of pulses/micron i.e. the overlapping rate. Applications can be numerous in fast material processing by the production of nanoporous matter, and photonics by changing the optical properties.展开更多
A type of photonic crystal fiber based on Kagome lattice cladding and slot air holes in a rectangular core is investigated. Full vector finite element method is used to evaluate the modal and propagation properties of...A type of photonic crystal fiber based on Kagome lattice cladding and slot air holes in a rectangular core is investigated. Full vector finite element method is used to evaluate the modal and propagation properties of the designed fiber.High birefringence of 0.089 and low effective material loss of 0.055 cm^-1 are obtained at 1 THz. The y-polarized fundamental mode of the designed fiber shows a flattened and near-zero dispersion of 0±0.45 ps · THz^-1· cm^-1 within a broad frequency range(0.5 THz–1.5 THz). Our results provide the theory basis for applications of the designed fiber in terahertz polarization maintaining systems.展开更多
Flow birefringent method and its data processing was reviewed and a new hybrid method offlow birefringence and boundary integration was introduced. The basic equations and boundary conditionssuitable to the hybrid met...Flow birefringent method and its data processing was reviewed and a new hybrid method offlow birefringence and boundary integration was introduced. The basic equations and boundary conditionssuitable to the hybrid method were derived, and a comparison of the hybrid and other classical methodswas given. Finally as an example, the flow in a step converging tube was analyzed by the given method.展开更多
Pulse-burst 1064-nm picosecond azimuthal polarization beam amplification up to an average power of 16.32 W using side-pumped Nd: YAG amplifiers has been demonstrated. The maximum envelop energy as much as 16.32 mJ, co...Pulse-burst 1064-nm picosecond azimuthal polarization beam amplification up to an average power of 16.32 W using side-pumped Nd: YAG amplifiers has been demonstrated. The maximum envelop energy as much as 16.32 mJ, corresponding to a power amplification factor of 299.5%. A simple criterion was defined to help estimate the amount of depolarization in Nd:YAG amplifier stages. The degree of depolarization of the beam was 7.1% and the beam quality was measured to be M2= 3.69. The reason for the azimuthal polarization depolarization and beam quality degradation were explained theoretically and experimentally during the amplification process.展开更多
We propose a new scheme for the coherent control of birefringent light pulses propagation in a four-level atomic medium. We modify the splitting of a light pulse by controlling the electric and magnetic responses. The...We propose a new scheme for the coherent control of birefringent light pulses propagation in a four-level atomic medium. We modify the splitting of a light pulse by controlling the electric and magnetic responses. The Doppler broadening effect is also noted on the propagation of the birefringent pulses. The dispersions of the birefringence beams are oppositely manipulated for delay and advancement of time at a Doppler width of 10γ. A time gap is created between the birefringence beams, which protects from hacking of information. The time gap is then closed to restore the pulse into the original form by a reverse manipulation of the dispersion of the birefringence beams, i.e., introducing another medium whose transfer function is the complex conjugate of that of the original medium. The results are useful for secure communication technology.展开更多
This paper demonstrates a room-temperature multiwavelength fibre laser with spacing-adjustability and wavelength-tunability. The nonlinear gain of self-excited stimulated Brillouin scattering can suppress mode competi...This paper demonstrates a room-temperature multiwavelength fibre laser with spacing-adjustability and wavelength-tunability. The nonlinear gain of self-excited stimulated Brillouin scattering can suppress mode competition induced by homogeneous broadening of Erbium-doped fibre. With the use of a birefringence fibre loop filter, the wavelength spacing can be adjusted by changing the length of the used birefringence fibre, and the lasing wavelengths can be finely tuned through modifying the filtering profile of the birefringence filter. Multiwavelength output with spectral spacing as small as 0.076 nm and a wavelength number of more than 80 has been successfully produced.展开更多
The influence of the circular birefringence on the measurement performance was analyzed based on the Polarization Properties of FBG in this paper. Due to the circular birefringence, the linear relationship between the...The influence of the circular birefringence on the measurement performance was analyzed based on the Polarization Properties of FBG in this paper. Due to the circular birefringence, the linear relationship between the max of PDL and pressure has been broken down. To estimate the cross sensitivity, a new parameter named relative peak of PDL (RPPDL) is proposed. Under different circular birefringence, the same pressure sensitivity of sensor has been achieved. The theo- retical analysis and experiment results prove that transverse strain sensor of FBG is insensitive to the circular birefrin- gence by applying the RPPDL. This research can be provided to useful and practical application.展开更多
Herein,two antimony sulfates,named RbSb(SO_(4))_(2)(1)and CsSb(SO_(4))_(2)(2),have been successfully synthesized with the introduction of Sb^(3+)cation with stereochemically active lone pairs(SCALP)into sulfates by th...Herein,two antimony sulfates,named RbSb(SO_(4))_(2)(1)and CsSb(SO_(4))_(2)(2),have been successfully synthesized with the introduction of Sb^(3+)cation with stereochemically active lone pairs(SCALP)into sulfates by the conventional hydrothermal method.Both two compounds endow short ultraviolet(UV)absorption edges(281 nm and 278 nm,respectively)and large birefringence(0.171@546 nm and 0.174@546 nm,respectively),which means that they are promising short-wave UV optical materials.Interestingly,though both of the two compounds exhibit similar 1D chained structures,and possess the same functional moieties including SbO4 seesaws and SO4 tetrahedral groups,they exhibit significantly opposite macroscopic symmetries,i.e.,compound 1 crystallizes in a centrosymmetric(CS)manner(P2_(1)/n)and compound 2 in a noncentrosymmetric(NCS)manner(P2_(1)2_(1)2_(1)),due to the size of cations[r(Rb+)=1.56 A˚,r(Cs+)=1.67 A˚]affects the orientation of SCALP of the adjacent Sb^(3+).展开更多
The development of optical films with high transparency,high thermal resistance and low birefringence remains a challenge in the flexible display industry.In this work,we designed and synthesized a series of fluorinat...The development of optical films with high transparency,high thermal resistance and low birefringence remains a challenge in the flexible display industry.In this work,we designed and synthesized a series of fluorinated colorless polyimides(CPIs)materials using 2,5-substituted m-phenylenediamine diamine monomers and 1,2,4,5-cyclohexanetetracarboxylic dianhydride(CHDA).We systematically studied the effects of fluorinated group substitutions on the thermal,mechanical,optical and dielectric properties of CPI films.The introduction of alicyclic CHDA dianhydride affords high transparency and low yellowness,while the 2,5-substituted m-phenylenediamine diamines offer the CPIs with quite low birefringence as well as high glass transition temperatures.A particular CHDA/o3FBDA film with simple chemical structure stands out,exhibiting well-balanced overall properties.展开更多
We demonstrate spectral-furcated vector solitons in normal-dispersion fiber lasers comprising a section of polarizationmaintaining fiber.The spectrum of each orthogonal-polarized component is confined by the birefring...We demonstrate spectral-furcated vector solitons in normal-dispersion fiber lasers comprising a section of polarizationmaintaining fiber.The spectrum of each orthogonal-polarized component is confined by the birefringence-related phasematching principle,and the bicorn spectral structure corresponds to the zero-order sidebands of two vector modes.Due to the Hopf bifurcation effect,the vector soliton evolves into a breathing state at the higher pump level,accompanied by an extra set of sub-sidebands that continuously exchange energy with the zero-order sidebands.Simulation results fully reproduce experimental observations of the spectral furcation and soliton breathing,offering comprehensive insights into the pulse-shaping mechanism of the birefringence-managed soliton.展开更多
Deep-ultraviolet(DUV,λ<200 nm)nonlinear-optical(NLO)crystals play a pivotal role in modern laser science and technology.Metal phosphates have been considered as fascinating candidates for DUV NLO crystal material....Deep-ultraviolet(DUV,λ<200 nm)nonlinear-optical(NLO)crystals play a pivotal role in modern laser science and technology.Metal phosphates have been considered as fascinating candidates for DUV NLO crystal material.However,how to generate both strong second-harmonic-generation(SHG)response and large birefringence for promising DUV NLO metal phosphates is a long-standing issue.Herein,a new DUV NLO metal phosphate,BaNa_(2)[PO_(3)(OH)]_(2),was successfully synthesized,which features a two-dimensional[NaPO_(3)(OH)]_(∞)alveolate layer alternately connected by highly asymmetric[PO_(3)(OH)]groups and NaO5 triangular bipyramids.BaNa_(2)[PO_(3)(OH)]_(2)can realize a good balance of DUV nonlinear properties covering short UV absorption edge less than 190 nm,strong SHG response with the magnitude of~1.2×benchmark KH_(2)PO_(4)(KDP),and the largest birefringence with the experimental value of 0.064@590±3 nm in reported alkaline/alkaline-earth metal phosphates,producing the shortest phase-matching output down to the wavelength of 164 nm.These research results show that BaNa_(2)[PO_(3)(OH)]_(2)crystal is a potential DUV NLO crystal material.展开更多
Nonlinear optical(NLO)materials play an increasingly important role in laser technology.Birefringence is one of the most important parameters for NLO materials to realize angle phase-matching conditions.In comparison ...Nonlinear optical(NLO)materials play an increasingly important role in laser technology.Birefringence is one of the most important parameters for NLO materials to realize angle phase-matching conditions.In comparison with other desirable optical properties,the availability of birefringence and refractive index dispersion is especially problematic owing to the strict requirements for single crystals.In this review,we described how to obtain the refractive index and birefringence of NLO materials from crystals sub-millimeters to centimeters in size.Espe-cially,recently developed methods including the minimum deflection angle method,auto-collimation method,prism coupling method,oil immersion technique,interference color method,and theoretical calculation(DFT)for rapid assessment of birefringence are summarized,the contents of which are mainly focused on the principles and typical applications,together with the advantages and drawbacks.In addition,representative examples of bire-fringent measurements were presented.The purpose of this work is to provide a useful perspective on the characterization of birefringence for NLO materials.It is hoped that this review can give a clear description of the birefringence measurements and accelerate the discovery of new NLO crystals.展开更多
Polarimetric imaging provides valuable insights into the polarization state of light interacting with a sample.It can infer crucial birefringence properties of specimens without using labels,thereby facilitating the d...Polarimetric imaging provides valuable insights into the polarization state of light interacting with a sample.It can infer crucial birefringence properties of specimens without using labels,thereby facilitating the diagnosis of diseases such as cancer and osteoarthritis.In this study,we present a novel polarimetric coded ptychography(pol-CP)approach that enables high-resolution,high-throughput gigapixel birefringence imaging on a chip.Our platform deviates from traditional lens-based systems by employing an integrated polarimetric coded sensor for lensless coherent diffraction imaging.Utilizing Jones calculus,we quantitatively determine the birefringence retardance and orientation information of biospecimens from the recovered images.Our portable pol-CP prototype can resolve the 435 nm linewidth on the resolution target,and the imaging field of view for a single acquisition is limited only by the detector size of 41 mm2.The prototype allows for the acquisition of gigapixel birefringence images with a 180 mm^(2) field of view in~3.5 min,a performance that rivals high-end whole slide scanner but at a small fraction of the cost.To demonstrate its biomedical applications,we perform high-throughput imaging of malaria-infected blood smears,locating parasites using birefringence contrast.We also generate birefringence maps of label-free thyroid smears to identify thyroid follicles.Notably,the recovered birefringence maps emphasize the same regions as autofluorescence images,underscoring the potential for rapid on-site evaluation of label-free biopsies.Our approach provides a turnkey and portable solution for lensless polarimetric analysis on a chip,with promising applications in disease diagnosis,crystal screening,and label-free chemical imaging,particularly in resource-constrained environments.展开更多
High birefringence with low confinement loss photonic crystal fiber (PCF) has significant advantages in the field of sensing, dispersion compensation devices, nonlinear applications, and polarization filter. In this r...High birefringence with low confinement loss photonic crystal fiber (PCF) has significant advantages in the field of sensing, dispersion compensation devices, nonlinear applications, and polarization filter. In this report, two different models of PCFs are presented and compared. Both the models contain five air holes rings with combination of circular and elliptical air holes arrangement. Moreover, the elliptical shaped air holes polarization and the third ring air holes rotational angle are varied. To examine different guiding characteristics, finite element method (FEM) with perfectly matched layer (PML) absorbing boundary condition is applied from 1.2 to 1.8 |im wavelength range. High birefringence, low confinement loss, high nonlinearity, and moderate disper-sion values are successfully achieved in both the PCFs models. Numeric analysis shows that model-1 gives higher birefringence (2.75 ×10^-2) and negative dispersion (-540.67 ps/(nm ·km)) at 1.55 |im wavelength. However, model-2 gives more small confinement loss than model-1 at the same wavelength. In addition, the proposed design demonstrates the variation of rotation angle has great impact to enhance guiding properties especially the birefringence.展开更多
White-light continuum can be induced by the interaction of intense femtosecond laser pulses with condensed materials.By using two orthogonal polarizers,a self-induced birefringence of continuum is observed when focusi...White-light continuum can be induced by the interaction of intense femtosecond laser pulses with condensed materials.By using two orthogonal polarizers,a self-induced birefringence of continuum is observed when focusing femtosecond laser pulses into bulk fused silica.That is,the generated white-light continuum is synchronously modulated anisotropically while propagating in fused silica.Time-resolved detection confirms that self-induced birefringence of continuum shows a growth and saturation feature with time evolution.By adjusting laser energy,the transmitted intensity of continuum modulated by self-induced birefringence also varies correspondingly.Morphology analysis with time evolution indicates that it is the focused femtosecond laser pulses that induce anisotropic microstructures in bulk fused silica,and the anisotropic structures at the same time modulate the generated continuum.展开更多
Polarization aberration caused by material birefringence can be partially compensated by lens clocking.In this Letter,we propose a fast and efficient clocking optimization method.First,the material birefringence distr...Polarization aberration caused by material birefringence can be partially compensated by lens clocking.In this Letter,we propose a fast and efficient clocking optimization method.First,the material birefringence distribution is fitted by the orientation Zernike polynomials.On this basis,the birefringence sensitivity matrix of each lens element can be calculated.Then we derive the rotation matrix of the orientation Zernike polynomials and establish a mathematical model for clocking optimization.Finally,an optimization example is given to illustrate the efficiency of the new method.The result shows that the maximum RMS of retardation is reduced by 64%using only 48.99 s.展开更多
In this paper, we report a novel method for accurately measuring the photo-induced birefringence of photosensitive fiber by using Mach-Zehnder interferometer. The results indicate that the normalized birefringence can...In this paper, we report a novel method for accurately measuring the photo-induced birefringence of photosensitive fiber by using Mach-Zehnder interferometer. The results indicate that the normalized birefringence can attain 10-5.展开更多
基金This work was supported by the National Natural Science Foundation of China (No. 19604015) and Guangdong Provincial Natural Science Foundation (No. 980279 and 980346).
文摘Photoinduced birefringence is investigated in a new amorphous copolymer containing azobenzene groups. The levels of birefringence signal are found to depend on the polarization angle between the pump beam and the probe beam, and on the ellipticity of the pump beam. Both the growth and decay processes of the birefringence signal can be described by known biexponential equations. The rate constants and the amplitudes associated with the growth process of the photoinduced birefringence are observed to display a linear dependence with the pump beam intensity. A new dynamic model of the photoinduced birefringence is presented taking into account the contributions of both the trans and cis isomers ofazobenzene groups and the local polymer segments. The numerical treatment of this model shows good agreement with the experimental data in the whole writing-erasing processes of the photoinduced birefringence conducted in our polymer samples.
基金Project supported by the National Natural Science Foundation of China(Grant No.61475029)
文摘A new type of V-shaped photonic crystal fiber with elliptical air-holes is proposed to realize simultaneous high birefringence and nonlinearity at a wavelength of 1.55μm.The full vector finite element method was adopted to investigate its characteristics,including birefringence,nonlinearity,and dispersion.The PCF exhibited a very high birefringence of 2.89×10^(-2) and very high nonlinear coefficient of 102.69 W^(-1)·km^(-1).In particular,there were two zero-dispersion wavelengths(ZDWs)in the visible(X:640-720 nm and Y:730-760 nm)and near-infrared regions(X:1050-1606 nm and Y:850-1500 nm).The combination of high birefringence and nonlinearity allowed the PCF to maintain the polarization state and generate a broadband super continuum,with potential applications in nonlinear optics.
基金The project supported by National Natural Science foundation of China.
文摘The formulas which are suitable to birefringent medium with symmetric plane are derived bymeans of phase retard integration.We have adopted this concept to the axisymmetric problems and deducedsome useful formulas for these cases.As a practical application,the strain rate analysis of flow in adiverging or a converging vessel is illustrated at the end of this paper.
文摘It is demonstrated that the form birefringence related to the so-called nanogratings is quantitatively correlated to the porosity-filling factor of these nanostructures. We reveal that matters surrounding the nanopores exhibit significant refractive index decrease which is likely due to the fictive temperature increase and/or the presence of a significant amount of interstitial O2. The control of the porosity was achieved by adjusting the laser pulse energy and the number of pulses/micron i.e. the overlapping rate. Applications can be numerous in fast material processing by the production of nanoporous matter, and photonics by changing the optical properties.
基金Project supported by the National Natural Science Foundation of China(Grant No.11604260)the Outstanding Youth Science Fund of Xi’an University of Science and Technology,China(Grant No.2019YQ3-10)
文摘A type of photonic crystal fiber based on Kagome lattice cladding and slot air holes in a rectangular core is investigated. Full vector finite element method is used to evaluate the modal and propagation properties of the designed fiber.High birefringence of 0.089 and low effective material loss of 0.055 cm^-1 are obtained at 1 THz. The y-polarized fundamental mode of the designed fiber shows a flattened and near-zero dispersion of 0±0.45 ps · THz^-1· cm^-1 within a broad frequency range(0.5 THz–1.5 THz). Our results provide the theory basis for applications of the designed fiber in terahertz polarization maintaining systems.
基金The project supported by National Natural Science Foundation of China (NSFC)
文摘Flow birefringent method and its data processing was reviewed and a new hybrid method offlow birefringence and boundary integration was introduced. The basic equations and boundary conditionssuitable to the hybrid method were derived, and a comparison of the hybrid and other classical methodswas given. Finally as an example, the flow in a step converging tube was analyzed by the given method.
基金Project supported by the National Natural Science Foundation of China(Grant No.U1631240)the Education Commission Program of BeijingBeijing Natural Science Foundation(Grant No.KZ201510005001)
文摘Pulse-burst 1064-nm picosecond azimuthal polarization beam amplification up to an average power of 16.32 W using side-pumped Nd: YAG amplifiers has been demonstrated. The maximum envelop energy as much as 16.32 mJ, corresponding to a power amplification factor of 299.5%. A simple criterion was defined to help estimate the amount of depolarization in Nd:YAG amplifier stages. The degree of depolarization of the beam was 7.1% and the beam quality was measured to be M2= 3.69. The reason for the azimuthal polarization depolarization and beam quality degradation were explained theoretically and experimentally during the amplification process.
文摘We propose a new scheme for the coherent control of birefringent light pulses propagation in a four-level atomic medium. We modify the splitting of a light pulse by controlling the electric and magnetic responses. The Doppler broadening effect is also noted on the propagation of the birefringent pulses. The dispersions of the birefringence beams are oppositely manipulated for delay and advancement of time at a Doppler width of 10γ. A time gap is created between the birefringence beams, which protects from hacking of information. The time gap is then closed to restore the pulse into the original form by a reverse manipulation of the dispersion of the birefringence beams, i.e., introducing another medium whose transfer function is the complex conjugate of that of the original medium. The results are useful for secure communication technology.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60702006, 60736002, 60807014, 60837004 and 60967002)China Postdoctoral Science Foundation, Open Fund of Key Laboratory of Information Photonics and Optical CommunicationsNatural Science Foundation of Jiangxi Province (Grant No. 2008GQS0050)
文摘This paper demonstrates a room-temperature multiwavelength fibre laser with spacing-adjustability and wavelength-tunability. The nonlinear gain of self-excited stimulated Brillouin scattering can suppress mode competition induced by homogeneous broadening of Erbium-doped fibre. With the use of a birefringence fibre loop filter, the wavelength spacing can be adjusted by changing the length of the used birefringence fibre, and the lasing wavelengths can be finely tuned through modifying the filtering profile of the birefringence filter. Multiwavelength output with spectral spacing as small as 0.076 nm and a wavelength number of more than 80 has been successfully produced.
文摘The influence of the circular birefringence on the measurement performance was analyzed based on the Polarization Properties of FBG in this paper. Due to the circular birefringence, the linear relationship between the max of PDL and pressure has been broken down. To estimate the cross sensitivity, a new parameter named relative peak of PDL (RPPDL) is proposed. Under different circular birefringence, the same pressure sensitivity of sensor has been achieved. The theo- retical analysis and experiment results prove that transverse strain sensor of FBG is insensitive to the circular birefrin- gence by applying the RPPDL. This research can be provided to useful and practical application.
基金the National Natural Science Foundation of China(Nos.22122106,22071158,21971171)the Fundamental Research Funds from Sichuan University(No.2021SCUNL101).
文摘Herein,two antimony sulfates,named RbSb(SO_(4))_(2)(1)and CsSb(SO_(4))_(2)(2),have been successfully synthesized with the introduction of Sb^(3+)cation with stereochemically active lone pairs(SCALP)into sulfates by the conventional hydrothermal method.Both two compounds endow short ultraviolet(UV)absorption edges(281 nm and 278 nm,respectively)and large birefringence(0.171@546 nm and 0.174@546 nm,respectively),which means that they are promising short-wave UV optical materials.Interestingly,though both of the two compounds exhibit similar 1D chained structures,and possess the same functional moieties including SbO4 seesaws and SO4 tetrahedral groups,they exhibit significantly opposite macroscopic symmetries,i.e.,compound 1 crystallizes in a centrosymmetric(CS)manner(P2_(1)/n)and compound 2 in a noncentrosymmetric(NCS)manner(P2_(1)2_(1)2_(1)),due to the size of cations[r(Rb+)=1.56 A˚,r(Cs+)=1.67 A˚]affects the orientation of SCALP of the adjacent Sb^(3+).
基金supported by the Natural Science Foundation of Guangdong Province(No.2022A1515010125)the Key-Area Research and Development Program of Guangdong Province(No.2020B010182002)+5 种基金the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515110543)the R&D Program of Guangzhou(No.2023A04J1577)the Major Program of National Natural Science Foundation of China(No.51890871)the Recruitment Program of Guangdong(No.2016ZT06C322)the 111 Project(No.B18023)Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application at Soochow University.
文摘The development of optical films with high transparency,high thermal resistance and low birefringence remains a challenge in the flexible display industry.In this work,we designed and synthesized a series of fluorinated colorless polyimides(CPIs)materials using 2,5-substituted m-phenylenediamine diamine monomers and 1,2,4,5-cyclohexanetetracarboxylic dianhydride(CHDA).We systematically studied the effects of fluorinated group substitutions on the thermal,mechanical,optical and dielectric properties of CPI films.The introduction of alicyclic CHDA dianhydride affords high transparency and low yellowness,while the 2,5-substituted m-phenylenediamine diamines offer the CPIs with quite low birefringence as well as high glass transition temperatures.A particular CHDA/o3FBDA film with simple chemical structure stands out,exhibiting well-balanced overall properties.
基金supported by the National Natural Science Foundation of China(No.12274344)the Natural Science Basic Research Program of Shaanxi Province(No.2021JC-09)the Fundamental Research Funds for the Central Universities(No.3102019JC008)。
文摘We demonstrate spectral-furcated vector solitons in normal-dispersion fiber lasers comprising a section of polarizationmaintaining fiber.The spectrum of each orthogonal-polarized component is confined by the birefringence-related phasematching principle,and the bicorn spectral structure corresponds to the zero-order sidebands of two vector modes.Due to the Hopf bifurcation effect,the vector soliton evolves into a breathing state at the higher pump level,accompanied by an extra set of sub-sidebands that continuously exchange energy with the zero-order sidebands.Simulation results fully reproduce experimental observations of the spectral furcation and soliton breathing,offering comprehensive insights into the pulse-shaping mechanism of the birefringence-managed soliton.
文摘Deep-ultraviolet(DUV,λ<200 nm)nonlinear-optical(NLO)crystals play a pivotal role in modern laser science and technology.Metal phosphates have been considered as fascinating candidates for DUV NLO crystal material.However,how to generate both strong second-harmonic-generation(SHG)response and large birefringence for promising DUV NLO metal phosphates is a long-standing issue.Herein,a new DUV NLO metal phosphate,BaNa_(2)[PO_(3)(OH)]_(2),was successfully synthesized,which features a two-dimensional[NaPO_(3)(OH)]_(∞)alveolate layer alternately connected by highly asymmetric[PO_(3)(OH)]groups and NaO5 triangular bipyramids.BaNa_(2)[PO_(3)(OH)]_(2)can realize a good balance of DUV nonlinear properties covering short UV absorption edge less than 190 nm,strong SHG response with the magnitude of~1.2×benchmark KH_(2)PO_(4)(KDP),and the largest birefringence with the experimental value of 0.064@590±3 nm in reported alkaline/alkaline-earth metal phosphates,producing the shortest phase-matching output down to the wavelength of 164 nm.These research results show that BaNa_(2)[PO_(3)(OH)]_(2)crystal is a potential DUV NLO crystal material.
基金supported by the National Natural Science Foundation of China(Grant No.21975062)Hebei Province Outstanding Youth Fund(Grant No.E2020201003)+1 种基金Science and Technology Project of Hebei Education Department(Grant Nos.ZD2022156,BJ2020020)Key Projects of Scientific Research and Cultivation Fund of Baoding University(Grant No.2022Z01).
文摘Nonlinear optical(NLO)materials play an increasingly important role in laser technology.Birefringence is one of the most important parameters for NLO materials to realize angle phase-matching conditions.In comparison with other desirable optical properties,the availability of birefringence and refractive index dispersion is especially problematic owing to the strict requirements for single crystals.In this review,we described how to obtain the refractive index and birefringence of NLO materials from crystals sub-millimeters to centimeters in size.Espe-cially,recently developed methods including the minimum deflection angle method,auto-collimation method,prism coupling method,oil immersion technique,interference color method,and theoretical calculation(DFT)for rapid assessment of birefringence are summarized,the contents of which are mainly focused on the principles and typical applications,together with the advantages and drawbacks.In addition,representative examples of bire-fringent measurements were presented.The purpose of this work is to provide a useful perspective on the characterization of birefringence for NLO materials.It is hoped that this review can give a clear description of the birefringence measurements and accelerate the discovery of new NLO crystals.
基金National Natural Science Foundation of China(61975254,62075175)。
文摘Polarimetric imaging provides valuable insights into the polarization state of light interacting with a sample.It can infer crucial birefringence properties of specimens without using labels,thereby facilitating the diagnosis of diseases such as cancer and osteoarthritis.In this study,we present a novel polarimetric coded ptychography(pol-CP)approach that enables high-resolution,high-throughput gigapixel birefringence imaging on a chip.Our platform deviates from traditional lens-based systems by employing an integrated polarimetric coded sensor for lensless coherent diffraction imaging.Utilizing Jones calculus,we quantitatively determine the birefringence retardance and orientation information of biospecimens from the recovered images.Our portable pol-CP prototype can resolve the 435 nm linewidth on the resolution target,and the imaging field of view for a single acquisition is limited only by the detector size of 41 mm2.The prototype allows for the acquisition of gigapixel birefringence images with a 180 mm^(2) field of view in~3.5 min,a performance that rivals high-end whole slide scanner but at a small fraction of the cost.To demonstrate its biomedical applications,we perform high-throughput imaging of malaria-infected blood smears,locating parasites using birefringence contrast.We also generate birefringence maps of label-free thyroid smears to identify thyroid follicles.Notably,the recovered birefringence maps emphasize the same regions as autofluorescence images,underscoring the potential for rapid on-site evaluation of label-free biopsies.Our approach provides a turnkey and portable solution for lensless polarimetric analysis on a chip,with promising applications in disease diagnosis,crystal screening,and label-free chemical imaging,particularly in resource-constrained environments.
文摘High birefringence with low confinement loss photonic crystal fiber (PCF) has significant advantages in the field of sensing, dispersion compensation devices, nonlinear applications, and polarization filter. In this report, two different models of PCFs are presented and compared. Both the models contain five air holes rings with combination of circular and elliptical air holes arrangement. Moreover, the elliptical shaped air holes polarization and the third ring air holes rotational angle are varied. To examine different guiding characteristics, finite element method (FEM) with perfectly matched layer (PML) absorbing boundary condition is applied from 1.2 to 1.8 |im wavelength range. High birefringence, low confinement loss, high nonlinearity, and moderate disper-sion values are successfully achieved in both the PCFs models. Numeric analysis shows that model-1 gives higher birefringence (2.75 ×10^-2) and negative dispersion (-540.67 ps/(nm ·km)) at 1.55 |im wavelength. However, model-2 gives more small confinement loss than model-1 at the same wavelength. In addition, the proposed design demonstrates the variation of rotation angle has great impact to enhance guiding properties especially the birefringence.
基金This research was supported by the National Key Research and Development Program of China(No.2016YFB1102402)the National Natural Science Foundation of China(No.61675214).
文摘White-light continuum can be induced by the interaction of intense femtosecond laser pulses with condensed materials.By using two orthogonal polarizers,a self-induced birefringence of continuum is observed when focusing femtosecond laser pulses into bulk fused silica.That is,the generated white-light continuum is synchronously modulated anisotropically while propagating in fused silica.Time-resolved detection confirms that self-induced birefringence of continuum shows a growth and saturation feature with time evolution.By adjusting laser energy,the transmitted intensity of continuum modulated by self-induced birefringence also varies correspondingly.Morphology analysis with time evolution indicates that it is the focused femtosecond laser pulses that induce anisotropic microstructures in bulk fused silica,and the anisotropic structures at the same time modulate the generated continuum.
基金This work was supported by the National Science and Technology Major Project(No.2016ZX02201)the State Key Laboratory of Laser Interaction with Matter(No.SKLLIM1804)the Jilin Scientific and Technological Development Program(No.20190302050GX).
文摘Polarization aberration caused by material birefringence can be partially compensated by lens clocking.In this Letter,we propose a fast and efficient clocking optimization method.First,the material birefringence distribution is fitted by the orientation Zernike polynomials.On this basis,the birefringence sensitivity matrix of each lens element can be calculated.Then we derive the rotation matrix of the orientation Zernike polynomials and establish a mathematical model for clocking optimization.Finally,an optimization example is given to illustrate the efficiency of the new method.The result shows that the maximum RMS of retardation is reduced by 64%using only 48.99 s.
基金Supported by the National "863" high technology project(2002AA313110)
文摘In this paper, we report a novel method for accurately measuring the photo-induced birefringence of photosensitive fiber by using Mach-Zehnder interferometer. The results indicate that the normalized birefringence can attain 10-5.