Polarization,the vector nature of electromagnetic waves,plays a vital role in optics.Polarization is characterized by the amplitude contrast and phase difference between two orthogonal polarization states.The present ...Polarization,the vector nature of electromagnetic waves,plays a vital role in optics.Polarization is characterized by the amplitude contrast and phase difference between two orthogonal polarization states.The present polarimeters usually perform a series of intensity measurements to carry out the polarization detection,making the process bulky and time-consuming.Thereby,compact and broadband-available polarimetry within a single snapshot is urgently demanded.We propose an all-liquid-crystal polarimeter for broadband polarization detection.It is cascaded by a q-plate and a polarization grating.The former is electrically tuned to meet the half-wave condition,whereas the latter is driven to deviate from this condition.After a polarized light passes through this device followed by a polarizer,its amplitude contrast and phase difference between orthogonal spins are read directly from the diffraction pattern.The intensity contrast between±1st orders depicts the amplitude contrast,whereas the rotating angle of the dark split reveals the phase difference.The Stokes parameters can be calculated accordingly.The polarimeter works in a broad spectral range of 470 to 1100 nm.Through presetting a q-plate array,polarization imaging is demonstrated.It supplies an all-liquid-crystal and full-visible-band tunable Stokes polarimeter that significantly promotes advances in polarization optics.展开更多
High-grade squamous intraepithelial lesion(HSIL)is regarded as a serious precancerous state of cervix,and it is easy to progress into cervical invasive carcinoma which highlights the importance of earlier diagnosis an...High-grade squamous intraepithelial lesion(HSIL)is regarded as a serious precancerous state of cervix,and it is easy to progress into cervical invasive carcinoma which highlights the importance of earlier diagnosis and treatment of cervical lesions.Pathologists examine the biopsied cervical epithelial tissue through a microscope.The pathological examination will take a long time and sometimes results in high inter-and intra-observer variability in outcomes.Polarization imaging techniques have broad application prospects for biomedical diagnosis such as breast,liver,colon,thyroid and so on.In our team,we have derived polarimetry feature parameters(PFPs)to characterize microstructural features in histological sections of breast tissues,and the accuracy for PFPs ranges from 0.82 to 0.91.Therefore,the aim of this paper is to distinguish automatically microstructural features between HSIL and cervical squamous cell carcinoma(CSCC)by means of polarization imaging techniques,and try to provide quantitative reference index for patho-logical diagnosis which can alleviate the workload of pathologists.Polarization images of the H&E stained histological slices were obtained by Mueller matrix microscope.The typical path-ological structure area was labeled by two experienced pathologists.Calculate the polarimetry basis parameter(PBP)statistics for this region.The PBP statistics(stat PBPs)are screened by mutual information(MI)method.The training method is based on a linear discriminant analysis(LDA)classier whichnds the most simplied linear combination from these stat PBPs and the accuracy remains constant to characterize the specic microstructural feature quantitatively in cervical squamous epithelium.We present results from 37 clinical patients with analysis regions of cervical squamous epithelium.The accuracy of PFP for recognizing HSIL and CSCC was 83.8%and 87.5%,respectively.This work demonstrates the ability of PFP to quantitatively charac-terize the cervical squamous epithelial lesions in the H&E pathological sections.Signicance:Polarization detection technology provides an effcient method for digital pathological diagnosis and points out a new way for automatic screening of pathological sections.展开更多
After decades of research and development, the WSR-88 D(NEXRAD) network in the United States was upgraded with dual-polarization capability, providing polarimetric radar data(PRD) that have the potential to improve we...After decades of research and development, the WSR-88 D(NEXRAD) network in the United States was upgraded with dual-polarization capability, providing polarimetric radar data(PRD) that have the potential to improve weather observations,quantification, forecasting, and warnings. The weather radar networks in China and other countries are also being upgraded with dual-polarization capability. Now, with radar polarimetry technology having matured, and PRD available both nationally and globally, it is important to understand the current status and future challenges and opportunities. The potential impact of PRD has been limited by their oftentimes subjective and empirical use. More importantly, the community has not begun to regularly derive from PRD the state parameters, such as water mixing ratios and number concentrations, used in numerical weather prediction(NWP) models.In this review, we summarize the current status of weather radar polarimetry, discuss the issues and limitations of PRD usage, and explore potential approaches to more efficiently use PRD for quantitative precipitation estimation and forecasting based on statistical retrieval with physical constraints where prior information is used and observation error is included. This approach aligns the observation-based retrievals favored by the radar meteorology community with the model-based analysis of the NWP community. We also examine the challenges and opportunities of polarimetric phased array radar research and development for future weather observation.展开更多
Imaging polarimetry is one of the most widely used analytical technologies for object detection and analysis.To date,most metasurface-based polarimetry techniques are severely limited by narrow operating bandwidths an...Imaging polarimetry is one of the most widely used analytical technologies for object detection and analysis.To date,most metasurface-based polarimetry techniques are severely limited by narrow operating bandwidths and inevitable crosstalk,leading to detrimental effects on imaging quality and measurement accuracy.Here,we propose a crosstalkfree broadband achromatic full Stokes imaging polarimeter consisting of polarization-sensitive dielectric metalenses,implemented by the principle of polarization-dependent phase optimization.Compared with the single-polarization optimization method,the average crosstalk has been reduced over three times under incident light with arbitrary polarization ranging from 9μm to 12μm,which guarantees the measurement of the polarization state more precisely.The experimental results indicate that the designed polarization-sensitive metalenses can effectively eliminate the chromatic aberration with polarization selectivity and negligible crosstalk.The measured average relative errors are 7.08%,8.62%,7.15%,and 7.59%at 9.3,9.6,10.3,and 10.6μm,respectively.Simultaneously,the broadband full polarization imaging capability of the device is also verified.This work is expected to have potential applications in wavefront detection,remote sensing,light-field imaging,and so forth.展开更多
An improved algorithm for multi-polarization reconstruction from compact polarimetry （CP） is proposed. According to two fundamental assumptions in compact polarimetric reconstruction, two improvements are proposed. ...An improved algorithm for multi-polarization reconstruction from compact polarimetry （CP） is proposed. According to two fundamental assumptions in compact polarimetric reconstruction, two improvements are proposed. Firstly, the four-component model-based decomposition algorithm is modified with a new volume scattering model. The decomposed helix scattering component is then used to deal with the non-reflection symmetry condition in compact polarimetric measurements. Using the decomposed power and considering the scattering mechanism of each component, an average relationship between copolarized and crosspolarized channels is developed over the original polarization state extrapolation model. E-SAR polarimetric data acquired over the Oberpfaffenhofen area and JPL/AIRSAR polarimetric data acquired over San Francisco are used for verification, and good reconstruction results are obtained, demonstrating the effectiveness of the proposed algorithm.展开更多
The C-band synthetic aperture radar（SAR） data from the Bohai Sea of China, the Labrador Sea in the Arctic and the Weddell Sea in the Antarctic are used to analyze and discuss the sea ice full polarimetric informatio...The C-band synthetic aperture radar（SAR） data from the Bohai Sea of China, the Labrador Sea in the Arctic and the Weddell Sea in the Antarctic are used to analyze and discuss the sea ice full polarimetric information reconstruction ability under compact polarimetric modes. The type of compact polarimetric mode which has the highest reconstructed accuracy is analyzed, along with the performance impact of the reconstructed pseudo quad-pol SAR data on the sea ice detection and sea ice classification. According to the assessment and analysis, it is recommended to adopt the CTLR mode for reconstructing the polarimetric parameters σ_（HH）~0,σ_（VV）~0, H and α,while for reconstructing the polarimetric parameters σ_（HV）~0, ρ_（H-V）, λ_1 and λ_2, it is recommended to use the π/4 mode.Moreover, it is recommended to use the π/4 mode in studying the action effects between the electromagnetic waves and sea ice, but it is recommended to use the CTLR mode for studying the sea ice classification.展开更多
Purpoe: To evaluate retinal nerve fiber layer (RNFL) thickness measurements in local normal Chinese subjects of different age groups and analyse the correlation of RNFL thickness with age using scanning laser polarime...Purpoe: To evaluate retinal nerve fiber layer (RNFL) thickness measurements in local normal Chinese subjects of different age groups and analyse the correlation of RNFL thickness with age using scanning laser polarimetry (SLP,GDxVCC). To assess the reproducibility of RNFL thickness measurement with GDxVCC. Methods: The RNFL thickness of 67 normal subjects (123 eyes) were measured by GDxVCC. The average TSNIT parameters were calculated. The differences of RNFL thickness between sex,right and left eyes,superior and inferior were compared. The relationship between RNFL thickness and age was analyzed with correlation analysis and linear regression analysis. The intraclass correlation coefficients (ICC) of three images in every eye were calculated. Results: The average peripapillary RNFL thickness at the superior,inferior and whole ellipse regions in 123 eyes of 67 normal subjects were (70.30±6.76)(?)m,(67.35±6.77)(?)m and (56.87±4.53)(?) m,respectively. The average TNSIT standard deviation was 23.68±4.61 and the average inter-eye symmetric value was 0.86±0.11. There were significant difference of RNFL thickness between superior and inferior (t=4.952,P < 0.001). There were significant difference of inferior RNFL thickness and TNSIT standard deviation between right and left eyes (P=0.005 and 0.002),while not significant difference of superior RNFL thickness and whole mean RNFL thickness between right and left eye (P=0.086 and 0.529). There was no significant difference in TSNIT parameters between different genders. There was a slight negative correlation average RNFL thickness in superior sector with age (decreased approximately 0.15 microns per year,P=0.047) in the subjects aged below 60 years old. The ICC values of RNFL thickness were >0.8 in superior,inferior and global. Conclusions: The RNFL thickness can be measured accurately by GDxVCC and the reproducibility of RNFL thickness measurement by GDxVCC is good. There was a slight negative correlation between average RNFL thickness in superior with age. More researches on the effects of age on RNFL thickness by GDxVCC are needed.展开更多
POLAR-2 is a gamma-ray burst(GRB)polarimeter that is designed to study the polarization in GRB radiation emissions,aiming to improve our knowledge of related mechanisms.POLAR-2 is expected to utilize an on-board polar...POLAR-2 is a gamma-ray burst(GRB)polarimeter that is designed to study the polarization in GRB radiation emissions,aiming to improve our knowledge of related mechanisms.POLAR-2 is expected to utilize an on-board polarimeter that is sensitive to soft X-rays(2-10 keV),called low-energy polarization detector.We have developed a new soft X-ray polari-zation detector prototype based on gas microchannel plates(GMCPs)and pixel chips(Topmetal).The GMCPs have bulk resistance,which prevents charging-up effects and ensures gain stability during operation.The detector is composed of low outgassing materials and is gas-sealed using a laser welding technique,ensuring long-term stability.A modulation factor of 41.28%±0.64% is obtained for a 4.5 keV polarized X-ray beam.A residual modulation of 1.96%±0.58% at 5.9 keV is observed for the entire sensitive area.展开更多
Metasurfaces are promising candidates for compact and versatile polarimetry.However,the highly dispersive nature of metasurfaces limits metasurface-based polarimetric devices to single-wavelength operation with narrow...Metasurfaces are promising candidates for compact and versatile polarimetry.However,the highly dispersive nature of metasurfaces limits metasurface-based polarimetric devices to single-wavelength operation with narrow bandwidths.In this study,we employ a multi-target optimization method to realize,both theoretically and experimentally,a full-Stokes metasurface grating for dual-wavelength(1310 and 1550 nm)polarimetry.The metasurface grating exhibited high-level polarization efficiencies of 65.89%and 64.78%at the respective wavelengths and a notably low degree of polarization errors for fully polarized light detection(<0.1).Our work provides a solid foundation for future development of multi-wavelength/broadband polarimetric platforms with enhanced performance and broader applicability.展开更多
The enhanced X-ray Timing and Polarimetry mission—eXTP is an exciting scientific space mission.As the PI of the mission,I am pleased to introduce briefly this special issue dedicated to six white papers on eXTP,inclu...The enhanced X-ray Timing and Polarimetry mission—eXTP is an exciting scientific space mission.As the PI of the mission,I am pleased to introduce briefly this special issue dedicated to six white papers on eXTP,including the mission white paper[1]and five science white papers[2-6].These are updated substantially from the white papers published in 2019[7-11],to account for the rapid developments of the field over the past several years and the new mission profile.展开更多
In this paper,we present the current status of the enhanced X-ray Timing and Polarimetry mission,which has been fully approved for launch in 2030.eXTP is a space science mission designed to study fundamental physics u...In this paper,we present the current status of the enhanced X-ray Timing and Polarimetry mission,which has been fully approved for launch in 2030.eXTP is a space science mission designed to study fundamental physics under extreme conditions of matter density,gravity,and magnetism.The mission aims at determining the equation of state of matter at supra-nuclear density,measuring the effects of quantum electro-dynamics,and understanding the dynamics of matter in strong-field gravity.In addition to investigating fundamental physics,the eXTP mission is poised to become a leading observatory for time-domain and multi-messenger astronomy in the 2030s,as well as providing observations of unprecedented quality on a variety of galactic and extragalactic objects.After briefly introducing the history and a summary of the scientific objectives of the eXTP mission,this paper presents a comprehensive overview of:(1)the cutting-edge technology,technical specifications,and anticipated performance of the mission’s scientific instruments;(2)the full mission profile,encompassing spacecraft design,operational capabilities,and ground segment infrastructure.展开更多
In this paper we present the enhanced X-ray Timing and Polarimetry mission—eXTP. eXTP is a space science mission designed to study fundamental physics under extreme conditions of density, gravity and magnetism. The m...In this paper we present the enhanced X-ray Timing and Polarimetry mission—eXTP. eXTP is a space science mission designed to study fundamental physics under extreme conditions of density, gravity and magnetism. The mission aims at determining the equation of state of matter at supra-nuclear density, measuring effects of QED, and understanding the dynamics of matter in strong-field gravity. In addition to investigating fundamental physics, eXTP will be a very powerful observatory for astrophysics that will provide observations of unprecedented quality on a variety of galactic and extragalactic objects. In particular, its wide field monitoring capabilities will be highly instrumental to detect the electro-magnetic counterparts of gravitational wave sources.The paper provides a detailed description of:(1) the technological and technical aspects, and the expected performance of the instruments of the scientific payload;(2) the elements and functions of the mission, from the spacecraft to the ground segment.展开更多
We report a spatially modulated polarimetry scheme by using a zero-order vortex half-wave retarder(ZVHR)and a spatial Fourier analysis method.A ZVHR is employed to analyze the input polarized light and convert it into...We report a spatially modulated polarimetry scheme by using a zero-order vortex half-wave retarder(ZVHR)and a spatial Fourier analysis method.A ZVHR is employed to analyze the input polarized light and convert it into a vectorial optical field,and an analyzer is set after the ZVHR to form an hourglass intensity pattern due to the spatial polarization modulation.Then,the input light’s Stokes parameters can be calculated by spatial Fourier analysis of the hourglass pattern with a single shot.The working principle of the polarimeter has been analyzed by the Stokes-Mueller formalism,and some quantitative measuring experiments of different polarization states have been demonstrated.The experimental results indicate that the proposed polarimeter is accurate,robust,and simple to use.展开更多
Polarization imaging finds applications in many areas, such as photoelasticity, ellipsometry, and biomedical imaging. A compact, snapshot, and high-efficiency imaging polarimeter is highly desirable for many applicati...Polarization imaging finds applications in many areas, such as photoelasticity, ellipsometry, and biomedical imaging. A compact, snapshot, and high-efficiency imaging polarimeter is highly desirable for many applications.Here, based on a single multifunctional geometric phase optical element(GPOE), a new method is proposed for high-efficiency snapshot imaging polarimetry. With tailored spatially varying orientation of each anisotropic unit cell, the GPOE works highly efficiently as both a spin sorter and a half-wave plate, enabling snapshot retrieving of a full Stokes vector of incident light. The designed GPOE is implemented in the form of liquid crystal fabricated with a photo-alignment technology, and its application in imaging polarimetry is experimentally demonstrated by retrieving full Stokes parameters of a cylinder vector beam. This method can also work in the form of plasmonic or dielectric metasurfaces, enabling ultra-compact polarization detection systems by monolithic integration with other devices such as metalenses.展开更多
Background Fundus changes associated with high myopia （HM） may mask those associated with primary open-angle glaucoma （POAG）. This study aim to determine the characteristics of RNFL thickness changes in patients w...Background Fundus changes associated with high myopia （HM） may mask those associated with primary open-angle glaucoma （POAG）. This study aim to determine the characteristics of RNFL thickness changes in patients with both POAG and HM and compare these to changes in patients with only HM. The diagnostic capabilities of both OCT and GDxVCC in this subset of patients are also evaluated. Methods Twenty-two eyes with POAG and HM （spherical equivalent （SE） between -6.0 and -12.0 D） were evaluated, and 22 eyes with HM were used for comparison. Characteristic retinal nerve fiber layer （RNFL） thickness profiles in patients with POAG and HM were examined using optical coherence tomography （OCT） and scanning laser polarimetry with variable corneal compensation （GDxVCC）, and the diagnostic capabilities of these imaging modalities were compared. RNFL parameters evaluated included superior average （Savg-GDx）, inferior average （lavg-GDx）, temporal-superior-nasal- inferior-temporal （TSNIT） average, and nerve fiber indicator （NFI） on GDxVCC and superior average （Savg-OCT）, inferior average （lavg-OCT）, nasal average （Navg-OCT）, temporal average （Tavg-OCT）, and average thickness （AvgThick-OCT） on OCT （fast RNFL scan）. Visual field testing was performed and defects were evaluated using mean defect （MD） and pattern standard deviation （PSD）. Results The RNFL parameters （P 〈0.05） significantly different between groups included Savg-GDx, lavg-GDx, TSNIT average, NFI, Savg-OCT, lavg-OCT, Tavg-OCT, and AvgThick-OCT. Significant correlations existed between TSNIT average and AvgThick-OCT （r=0.778）, TSNIT average and MD （r=0.749）, AvgThick-OCT and MD （r=0.647）, TSNIT average and PSD （r=-0.756）, and AvgThick-OCT and PSD （r=-0.784）. The area under the receiver operating characteristic curve （AUROC） values of TSNIT average, Savg-GDx, lavg-GDx, NFI, Savg-OCT, lavg-OCT, Navg-OCT, Tavg-OCT, and AvgThick-OCT were 0.947, 0.962, 0.973, 0.994, 0.909, 0.917, 0.511, 0.906, and 0.913, respectively. The NFI AUROC was the highest value. Conclusions RNFL thickness was significantly lower in all but the nasal quadrant in patients with POAG and HM, compared to patients with only HM. Measurements with OCT and GDxVCC were well-correlated, and both modalities detected RNFL thickness chanaes. However. GDxVCC was better than OCT in detectina POAG in HM Datients.展开更多
Sensitive X-ray polarimetry in the keV energy range can be achieved by measuring the azimuthal angle distribution of emitted electrons after the photoelectric absorption of X-rays in a micropattern gas detector. Howev...Sensitive X-ray polarimetry in the keV energy range can be achieved by measuring the azimuthal angle distribution of emitted electrons after the photoelectric absorption of X-rays in a micropattern gas detector. However, the initial direction of the electron is not readily measurable due to the randomization of its motion during energy loss. By using the Geant4, Maxwell and Garfield packages, we simulated the detected electron tracks following photoelectric absorption, electron drift and diffusion in the gas, and proposed a technique capable of reconstructing the initial direction of the emitted photoelectron. The technique allows us to measure the angular modulation of flux predicted for a polarized X-ray beam. We calculated the modulation factors in 2-10 keV with a gas mixture of neon and CO;, and discussed how electron diffusion along the drift will dilute the track and suppress the modulation. These results are useful for the design of the X-ray polarimeter.展开更多
Automation of plant phenotyping using data from high-dimensional imaging sensors is on the forefront of agricultural research for its potential to improve seasonal yield by monitoring crop health and accelerating bree...Automation of plant phenotyping using data from high-dimensional imaging sensors is on the forefront of agricultural research for its potential to improve seasonal yield by monitoring crop health and accelerating breeding programs.A common challenge when capturing images in the field relates to the spectral reflection of sunlight(glare)from crop leaves that,at certain solar incidences and sensor viewing angles,presents unwanted signals.The research presented here involves the convergence of 2 parallel projects to develop a facile algorithm that can use polarization data to decouple light reflected from the surface of the leaves and light scattered from the leaf's tissue.展开更多
Polarimetry is a highly sensitive method to quantify changes of the polarization state of light when passing through matter and is therefore widely applied in material science.The progress of synchrotron and X-ray fre...Polarimetry is a highly sensitive method to quantify changes of the polarization state of light when passing through matter and is therefore widely applied in material science.The progress of synchrotron and X-ray free electron laser(XFEL)sources has led to significant developments of X-ray polarizers,opening perspectives for new applications of polarimetry to study source and beamline parameters as well as sample characteristics.X-ray polarimetry has shown to date a polarization purity of less than 1.4×10^(-11),enabling the detection of very small signals from ultrafast phenomena.A prominent application is the detection of vacuum birefringence.Vacuum birefringence is predicted in quantum electrodynamics and is expected to be probed by combining an XFEL with a petawatt-class optical laser.We review how source and optical elements affect X-ray polarimeters in general and which qualities are required for the detection of vacuum birefringence.展开更多
Continuously growing attention has been paid to potential of polarimetry to provide additional information of remote sounding of the earth and other planets and to detect some special targets. In the present paper the...Continuously growing attention has been paid to potential of polarimetry to provide additional information of remote sounding of the earth and other planets and to detect some special targets. In the present paper the polarimetric technique in space for all the four Stockes parameters is presented.展开更多
More durable[with high impact force],lighter,and more compact flexible azo dye micropolarizers are attractive candidates for low-cost,simple polarization imaging systems.The liquid crystal polymer[LCP],as an emerging ...More durable[with high impact force],lighter,and more compact flexible azo dye micropolarizers are attractive candidates for low-cost,simple polarization imaging systems.The liquid crystal polymer[LCP],as an emerging material developed by photo-alignment technology,is a potential material for organizing the long-range ordered structure of azo dyes.However,little research has been done on LCP aligned azo dyes.This paper points out and solves a key problem that restricts the fabrication of high-precision arrays in vip[azo dye]-host[LCP]systems:the doping of dyes leads to disorder of the LCP during curing.After solving the problem,the relationship between the thickness of the LCP and the extinction ratio of the polarizing film was investigated,which effectively improved the extinction ratio.Alignment of azo dye molecules in the range of 2μm[0°-180°]and arrays of micropolarizers[0°,45°,90°,-45°]with 8μm×8μm pixel pitch was achieved by laser direct writing technology.The bending cycle test demonstrates the mechanical stability of the ultrathin flexible polarizer.The flexible patterned polarizer with robust chemical and mechanical stabilities provides a flexible way to capture the polarization of the light and highly integrated advanced flexible optoelectronic devices.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2022YFA1203700)the National Natural Science Foundation of China(Grant Nos.62405129 and 62035008)+4 种基金the Natural Science Foundation of Jiangsu Province(Grant No.BK20241197)the China Postdoctoral Science Foundation(Grant No.2024T170396)the Postdoctoral Fellowship Program of CPSF(Grant No.GZC20240678)the Jiangsu Funding Program for Excellent Postdoctoral Talent(Grant No.2024ZB684)the Fundamental Research Funds for the Central Universities(Grant No.021314380244).
文摘Polarization,the vector nature of electromagnetic waves,plays a vital role in optics.Polarization is characterized by the amplitude contrast and phase difference between two orthogonal polarization states.The present polarimeters usually perform a series of intensity measurements to carry out the polarization detection,making the process bulky and time-consuming.Thereby,compact and broadband-available polarimetry within a single snapshot is urgently demanded.We propose an all-liquid-crystal polarimeter for broadband polarization detection.It is cascaded by a q-plate and a polarization grating.The former is electrically tuned to meet the half-wave condition,whereas the latter is driven to deviate from this condition.After a polarized light passes through this device followed by a polarizer,its amplitude contrast and phase difference between orthogonal spins are read directly from the diffraction pattern.The intensity contrast between±1st orders depicts the amplitude contrast,whereas the rotating angle of the dark split reveals the phase difference.The Stokes parameters can be calculated accordingly.The polarimeter works in a broad spectral range of 470 to 1100 nm.Through presetting a q-plate array,polarization imaging is demonstrated.It supplies an all-liquid-crystal and full-visible-band tunable Stokes polarimeter that significantly promotes advances in polarization optics.
基金the Guangming District Economic Development Special Fund(2020R01043)。
文摘High-grade squamous intraepithelial lesion(HSIL)is regarded as a serious precancerous state of cervix,and it is easy to progress into cervical invasive carcinoma which highlights the importance of earlier diagnosis and treatment of cervical lesions.Pathologists examine the biopsied cervical epithelial tissue through a microscope.The pathological examination will take a long time and sometimes results in high inter-and intra-observer variability in outcomes.Polarization imaging techniques have broad application prospects for biomedical diagnosis such as breast,liver,colon,thyroid and so on.In our team,we have derived polarimetry feature parameters(PFPs)to characterize microstructural features in histological sections of breast tissues,and the accuracy for PFPs ranges from 0.82 to 0.91.Therefore,the aim of this paper is to distinguish automatically microstructural features between HSIL and cervical squamous cell carcinoma(CSCC)by means of polarization imaging techniques,and try to provide quantitative reference index for patho-logical diagnosis which can alleviate the workload of pathologists.Polarization images of the H&E stained histological slices were obtained by Mueller matrix microscope.The typical path-ological structure area was labeled by two experienced pathologists.Calculate the polarimetry basis parameter(PBP)statistics for this region.The PBP statistics(stat PBPs)are screened by mutual information(MI)method.The training method is based on a linear discriminant analysis(LDA)classier whichnds the most simplied linear combination from these stat PBPs and the accuracy remains constant to characterize the specic microstructural feature quantitatively in cervical squamous epithelium.We present results from 37 clinical patients with analysis regions of cervical squamous epithelium.The accuracy of PFP for recognizing HSIL and CSCC was 83.8%and 87.5%,respectively.This work demonstrates the ability of PFP to quantitatively charac-terize the cervical squamous epithelial lesions in the H&E pathological sections.Signicance:Polarization detection technology provides an effcient method for digital pathological diagnosis and points out a new way for automatic screening of pathological sections.
基金supported by the NOAA (Grant Nos. NA16AOR4320115 and NA11OAR4320072)NSF (Grant No. AGS-1341878)
文摘After decades of research and development, the WSR-88 D(NEXRAD) network in the United States was upgraded with dual-polarization capability, providing polarimetric radar data(PRD) that have the potential to improve weather observations,quantification, forecasting, and warnings. The weather radar networks in China and other countries are also being upgraded with dual-polarization capability. Now, with radar polarimetry technology having matured, and PRD available both nationally and globally, it is important to understand the current status and future challenges and opportunities. The potential impact of PRD has been limited by their oftentimes subjective and empirical use. More importantly, the community has not begun to regularly derive from PRD the state parameters, such as water mixing ratios and number concentrations, used in numerical weather prediction(NWP) models.In this review, we summarize the current status of weather radar polarimetry, discuss the issues and limitations of PRD usage, and explore potential approaches to more efficiently use PRD for quantitative precipitation estimation and forecasting based on statistical retrieval with physical constraints where prior information is used and observation error is included. This approach aligns the observation-based retrievals favored by the radar meteorology community with the model-based analysis of the NWP community. We also examine the challenges and opportunities of polarimetric phased array radar research and development for future weather observation.
基金Sichuan Science and Technology Program(2020YFJ0001)the National Natural Science Foundation of China(61975210,62222513)+1 种基金National Key Research and Development Program(SQ2021YFA1400121)China Postdoctoral Science Foundation(2021T140670)
文摘Imaging polarimetry is one of the most widely used analytical technologies for object detection and analysis.To date,most metasurface-based polarimetry techniques are severely limited by narrow operating bandwidths and inevitable crosstalk,leading to detrimental effects on imaging quality and measurement accuracy.Here,we propose a crosstalkfree broadband achromatic full Stokes imaging polarimeter consisting of polarization-sensitive dielectric metalenses,implemented by the principle of polarization-dependent phase optimization.Compared with the single-polarization optimization method,the average crosstalk has been reduced over three times under incident light with arbitrary polarization ranging from 9μm to 12μm,which guarantees the measurement of the polarization state more precisely.The experimental results indicate that the designed polarization-sensitive metalenses can effectively eliminate the chromatic aberration with polarization selectivity and negligible crosstalk.The measured average relative errors are 7.08%,8.62%,7.15%,and 7.59%at 9.3,9.6,10.3,and 10.6μm,respectively.Simultaneously,the broadband full polarization imaging capability of the device is also verified.This work is expected to have potential applications in wavefront detection,remote sensing,light-field imaging,and so forth.
基金supported by the National Natural Science Foundation of China(41171317)the State Key Program of the Natural Science Foundation of China(61132008)the Research Foundation of Tsinghua University
文摘An improved algorithm for multi-polarization reconstruction from compact polarimetry （CP） is proposed. According to two fundamental assumptions in compact polarimetric reconstruction, two improvements are proposed. Firstly, the four-component model-based decomposition algorithm is modified with a new volume scattering model. The decomposed helix scattering component is then used to deal with the non-reflection symmetry condition in compact polarimetric measurements. Using the decomposed power and considering the scattering mechanism of each component, an average relationship between copolarized and crosspolarized channels is developed over the original polarization state extrapolation model. E-SAR polarimetric data acquired over the Oberpfaffenhofen area and JPL/AIRSAR polarimetric data acquired over San Francisco are used for verification, and good reconstruction results are obtained, demonstrating the effectiveness of the proposed algorithm.
基金The National Science Foundation for Young Scientists of China under contract No.41306193the National Special Research Fund for Non-profit Marine Sector under contract No.201305025-2the Dragon 3 Cooperation Programme under contract No.10501 by the Ministry of Science and Technology of the P.R.China and the European Space Agency
文摘The C-band synthetic aperture radar（SAR） data from the Bohai Sea of China, the Labrador Sea in the Arctic and the Weddell Sea in the Antarctic are used to analyze and discuss the sea ice full polarimetric information reconstruction ability under compact polarimetric modes. The type of compact polarimetric mode which has the highest reconstructed accuracy is analyzed, along with the performance impact of the reconstructed pseudo quad-pol SAR data on the sea ice detection and sea ice classification. According to the assessment and analysis, it is recommended to adopt the CTLR mode for reconstructing the polarimetric parameters σ_（HH）~0,σ_（VV）~0, H and α,while for reconstructing the polarimetric parameters σ_（HV）~0, ρ_（H-V）, λ_1 and λ_2, it is recommended to use the π/4 mode.Moreover, it is recommended to use the π/4 mode in studying the action effects between the electromagnetic waves and sea ice, but it is recommended to use the CTLR mode for studying the sea ice classification.
文摘Purpoe: To evaluate retinal nerve fiber layer (RNFL) thickness measurements in local normal Chinese subjects of different age groups and analyse the correlation of RNFL thickness with age using scanning laser polarimetry (SLP,GDxVCC). To assess the reproducibility of RNFL thickness measurement with GDxVCC. Methods: The RNFL thickness of 67 normal subjects (123 eyes) were measured by GDxVCC. The average TSNIT parameters were calculated. The differences of RNFL thickness between sex,right and left eyes,superior and inferior were compared. The relationship between RNFL thickness and age was analyzed with correlation analysis and linear regression analysis. The intraclass correlation coefficients (ICC) of three images in every eye were calculated. Results: The average peripapillary RNFL thickness at the superior,inferior and whole ellipse regions in 123 eyes of 67 normal subjects were (70.30±6.76)(?)m,(67.35±6.77)(?)m and (56.87±4.53)(?) m,respectively. The average TNSIT standard deviation was 23.68±4.61 and the average inter-eye symmetric value was 0.86±0.11. There were significant difference of RNFL thickness between superior and inferior (t=4.952,P < 0.001). There were significant difference of inferior RNFL thickness and TNSIT standard deviation between right and left eyes (P=0.005 and 0.002),while not significant difference of superior RNFL thickness and whole mean RNFL thickness between right and left eye (P=0.086 and 0.529). There was no significant difference in TSNIT parameters between different genders. There was a slight negative correlation average RNFL thickness in superior sector with age (decreased approximately 0.15 microns per year,P=0.047) in the subjects aged below 60 years old. The ICC values of RNFL thickness were >0.8 in superior,inferior and global. Conclusions: The RNFL thickness can be measured accurately by GDxVCC and the reproducibility of RNFL thickness measurement by GDxVCC is good. There was a slight negative correlation between average RNFL thickness in superior with age. More researches on the effects of age on RNFL thickness by GDxVCC are needed.
基金supported by Department of Physics and GXUNAOC Center for Astrophysics and Space Sciences,Guangxi UniversityThe National Natural Science Foundation of China(Nos.12027803,U1731239,12133003,12175241,U1938201,U1732266)the Guangxi Science Foundation(Nos.2018GXNSFGA281007,2018JJA110048).
文摘POLAR-2 is a gamma-ray burst(GRB)polarimeter that is designed to study the polarization in GRB radiation emissions,aiming to improve our knowledge of related mechanisms.POLAR-2 is expected to utilize an on-board polarimeter that is sensitive to soft X-rays(2-10 keV),called low-energy polarization detector.We have developed a new soft X-ray polari-zation detector prototype based on gas microchannel plates(GMCPs)and pixel chips(Topmetal).The GMCPs have bulk resistance,which prevents charging-up effects and ensures gain stability during operation.The detector is composed of low outgassing materials and is gas-sealed using a laser welding technique,ensuring long-term stability.A modulation factor of 41.28%±0.64% is obtained for a 4.5 keV polarized X-ray beam.A residual modulation of 1.96%±0.58% at 5.9 keV is observed for the entire sensitive area.
基金financial support from the National Key R&D Program of NQI Key Special Program(No.2024YFF0618000)the National Natural Science Foundation of China(No.62405301)+2 种基金the financial support from the National Natural Science Foundation of China(Nos.92463311,62322511,and 62275230)the financial support from the National Natural Science Foundation of China(No.62475237)the Natural Science Foundation of Zhejiang Province(No.LMS25F050003)。
文摘Metasurfaces are promising candidates for compact and versatile polarimetry.However,the highly dispersive nature of metasurfaces limits metasurface-based polarimetric devices to single-wavelength operation with narrow bandwidths.In this study,we employ a multi-target optimization method to realize,both theoretically and experimentally,a full-Stokes metasurface grating for dual-wavelength(1310 and 1550 nm)polarimetry.The metasurface grating exhibited high-level polarization efficiencies of 65.89%and 64.78%at the respective wavelengths and a notably low degree of polarization errors for fully polarized light detection(<0.1).Our work provides a solid foundation for future development of multi-wavelength/broadband polarimetric platforms with enhanced performance and broader applicability.
文摘The enhanced X-ray Timing and Polarimetry mission—eXTP is an exciting scientific space mission.As the PI of the mission,I am pleased to introduce briefly this special issue dedicated to six white papers on eXTP,including the mission white paper[1]and five science white papers[2-6].These are updated substantially from the white papers published in 2019[7-11],to account for the rapid developments of the field over the past several years and the new mission profile.
基金the support of the National Natural Science Foundation of China(Grant No.12333007)the International Partnership Program of Chinese Academy of Sciences(Grant No.113111KYSB20190020)+4 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA15020100)support by ASI,under the dedicated eXTP agreements and agreement ASI-INAF n.2017-14-H.O.by INAF and INFN under project REDSOXsupport from the Deutsche Zentrum für Luft-und Raumfahrt,the German Aerospace Center(DLR)support from MINECO grant ESP2017-82674-R and FEDER funds.
文摘In this paper,we present the current status of the enhanced X-ray Timing and Polarimetry mission,which has been fully approved for launch in 2030.eXTP is a space science mission designed to study fundamental physics under extreme conditions of matter density,gravity,and magnetism.The mission aims at determining the equation of state of matter at supra-nuclear density,measuring the effects of quantum electro-dynamics,and understanding the dynamics of matter in strong-field gravity.In addition to investigating fundamental physics,the eXTP mission is poised to become a leading observatory for time-domain and multi-messenger astronomy in the 2030s,as well as providing observations of unprecedented quality on a variety of galactic and extragalactic objects.After briefly introducing the history and a summary of the scientific objectives of the eXTP mission,this paper presents a comprehensive overview of:(1)the cutting-edge technology,technical specifications,and anticipated performance of the mission’s scientific instruments;(2)the full mission profile,encompassing spacecraft design,operational capabilities,and ground segment infrastructure.
基金support of the Chinese Academy of Sciences through the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA15020100)support by ASI, under the dedicated eXTP agreements and agreement ASI-INAF (Grant No. 2017-14-H.O.)+3 种基金by INAF and INFN under project REDSOXsupport from the Deutsche Zentrum für Luft- und Raumfahrt, the German Aerospce Center (DLR)support of Science Centre (Grant No. 2013/10/M/ST9/00729)support from MINECO (Grant No. ESP2017-82674-R) and FEDER funds
文摘In this paper we present the enhanced X-ray Timing and Polarimetry mission—eXTP. eXTP is a space science mission designed to study fundamental physics under extreme conditions of density, gravity and magnetism. The mission aims at determining the equation of state of matter at supra-nuclear density, measuring effects of QED, and understanding the dynamics of matter in strong-field gravity. In addition to investigating fundamental physics, eXTP will be a very powerful observatory for astrophysics that will provide observations of unprecedented quality on a variety of galactic and extragalactic objects. In particular, its wide field monitoring capabilities will be highly instrumental to detect the electro-magnetic counterparts of gravitational wave sources.The paper provides a detailed description of:(1) the technological and technical aspects, and the expected performance of the instruments of the scientific payload;(2) the elements and functions of the mission, from the spacecraft to the ground segment.
基金supported by the National Natural Science Foundation of China(NSFC)(No.61975235)the Natural Science Foundation of Hunan Province(No.2019JJ40342)。
文摘We report a spatially modulated polarimetry scheme by using a zero-order vortex half-wave retarder(ZVHR)and a spatial Fourier analysis method.A ZVHR is employed to analyze the input polarized light and convert it into a vectorial optical field,and an analyzer is set after the ZVHR to form an hourglass intensity pattern due to the spatial polarization modulation.Then,the input light’s Stokes parameters can be calculated by spatial Fourier analysis of the hourglass pattern with a single shot.The working principle of the polarimeter has been analyzed by the Stokes-Mueller formalism,and some quantitative measuring experiments of different polarization states have been demonstrated.The experimental results indicate that the proposed polarimeter is accurate,robust,and simple to use.
基金National Natural Science Foundation of China(NSFC)(11604219,61427819,61490712,61605117,91750205,U1701661)Natural Science Foundation of Guangdong Province(2016A030310063,2016A030312010,2017A030313351)+2 种基金Shenzhen Science and Technology Innovation Commission(JCYJ20180507182035270,JCYJ2017818144338999,KQTD2017033011044403,ZDSYS201703031605029)Ministry of Science and Technology of the People’s Republic of China(MOST)(2015CB352004)Guangdong Science and Technology Department(GDSTC)(00201505)
文摘Polarization imaging finds applications in many areas, such as photoelasticity, ellipsometry, and biomedical imaging. A compact, snapshot, and high-efficiency imaging polarimeter is highly desirable for many applications.Here, based on a single multifunctional geometric phase optical element(GPOE), a new method is proposed for high-efficiency snapshot imaging polarimetry. With tailored spatially varying orientation of each anisotropic unit cell, the GPOE works highly efficiently as both a spin sorter and a half-wave plate, enabling snapshot retrieving of a full Stokes vector of incident light. The designed GPOE is implemented in the form of liquid crystal fabricated with a photo-alignment technology, and its application in imaging polarimetry is experimentally demonstrated by retrieving full Stokes parameters of a cylinder vector beam. This method can also work in the form of plasmonic or dielectric metasurfaces, enabling ultra-compact polarization detection systems by monolithic integration with other devices such as metalenses.
文摘Background Fundus changes associated with high myopia （HM） may mask those associated with primary open-angle glaucoma （POAG）. This study aim to determine the characteristics of RNFL thickness changes in patients with both POAG and HM and compare these to changes in patients with only HM. The diagnostic capabilities of both OCT and GDxVCC in this subset of patients are also evaluated. Methods Twenty-two eyes with POAG and HM （spherical equivalent （SE） between -6.0 and -12.0 D） were evaluated, and 22 eyes with HM were used for comparison. Characteristic retinal nerve fiber layer （RNFL） thickness profiles in patients with POAG and HM were examined using optical coherence tomography （OCT） and scanning laser polarimetry with variable corneal compensation （GDxVCC）, and the diagnostic capabilities of these imaging modalities were compared. RNFL parameters evaluated included superior average （Savg-GDx）, inferior average （lavg-GDx）, temporal-superior-nasal- inferior-temporal （TSNIT） average, and nerve fiber indicator （NFI） on GDxVCC and superior average （Savg-OCT）, inferior average （lavg-OCT）, nasal average （Navg-OCT）, temporal average （Tavg-OCT）, and average thickness （AvgThick-OCT） on OCT （fast RNFL scan）. Visual field testing was performed and defects were evaluated using mean defect （MD） and pattern standard deviation （PSD）. Results The RNFL parameters （P 〈0.05） significantly different between groups included Savg-GDx, lavg-GDx, TSNIT average, NFI, Savg-OCT, lavg-OCT, Tavg-OCT, and AvgThick-OCT. Significant correlations existed between TSNIT average and AvgThick-OCT （r=0.778）, TSNIT average and MD （r=0.749）, AvgThick-OCT and MD （r=0.647）, TSNIT average and PSD （r=-0.756）, and AvgThick-OCT and PSD （r=-0.784）. The area under the receiver operating characteristic curve （AUROC） values of TSNIT average, Savg-GDx, lavg-GDx, NFI, Savg-OCT, lavg-OCT, Navg-OCT, Tavg-OCT, and AvgThick-OCT were 0.947, 0.962, 0.973, 0.994, 0.909, 0.917, 0.511, 0.906, and 0.913, respectively. The NFI AUROC was the highest value. Conclusions RNFL thickness was significantly lower in all but the nasal quadrant in patients with POAG and HM, compared to patients with only HM. Measurements with OCT and GDxVCC were well-correlated, and both modalities detected RNFL thickness chanaes. However. GDxVCC was better than OCT in detectina POAG in HM Datients.
基金Supported by NSFC(10903004,10978001)973 Program (2009CB824800)
文摘Sensitive X-ray polarimetry in the keV energy range can be achieved by measuring the azimuthal angle distribution of emitted electrons after the photoelectric absorption of X-rays in a micropattern gas detector. However, the initial direction of the electron is not readily measurable due to the randomization of its motion during energy loss. By using the Geant4, Maxwell and Garfield packages, we simulated the detected electron tracks following photoelectric absorption, electron drift and diffusion in the gas, and proposed a technique capable of reconstructing the initial direction of the emitted photoelectron. The technique allows us to measure the angular modulation of flux predicted for a polarized X-ray beam. We calculated the modulation factors in 2-10 keV with a gas mixture of neon and CO;, and discussed how electron diffusion along the drift will dilute the track and suppress the modulation. These results are useful for the design of the X-ray polarimeter.
基金supported by Division of Electrical,Communications and Cyber Systems(1809753)National Institute of Food and Agriculture(2020-67021-31961).
文摘Automation of plant phenotyping using data from high-dimensional imaging sensors is on the forefront of agricultural research for its potential to improve seasonal yield by monitoring crop health and accelerating breeding programs.A common challenge when capturing images in the field relates to the spectral reflection of sunlight(glare)from crop leaves that,at certain solar incidences and sensor viewing angles,presents unwanted signals.The research presented here involves the convergence of 2 parallel projects to develop a facile algorithm that can use polarization data to decouple light reflected from the surface of the leaves and light scattered from the leaf's tissue.
基金the China Scholarship Council for financial support(No.201908310159)The support of the High Energy Density Department at Helmholtz-Zentrum Dresden–Rossendorf+1 种基金the Ministry of Science and Technology of the People’s Republic of China(Grant No.2018YFA0404803)the National Natural Science Foundation of China(Grant No.11935008)
文摘Polarimetry is a highly sensitive method to quantify changes of the polarization state of light when passing through matter and is therefore widely applied in material science.The progress of synchrotron and X-ray free electron laser(XFEL)sources has led to significant developments of X-ray polarizers,opening perspectives for new applications of polarimetry to study source and beamline parameters as well as sample characteristics.X-ray polarimetry has shown to date a polarization purity of less than 1.4×10^(-11),enabling the detection of very small signals from ultrafast phenomena.A prominent application is the detection of vacuum birefringence.Vacuum birefringence is predicted in quantum electrodynamics and is expected to be probed by combining an XFEL with a petawatt-class optical laser.We review how source and optical elements affect X-ray polarimeters in general and which qualities are required for the detection of vacuum birefringence.
文摘Continuously growing attention has been paid to potential of polarimetry to provide additional information of remote sounding of the earth and other planets and to detect some special targets. In the present paper the polarimetric technique in space for all the four Stockes parameters is presented.
基金supported by the Changsha Municipal Natural Science Foundation(No.kq2014059)the School-Enterprise Cooperation Project(No.900201900966)。
文摘More durable[with high impact force],lighter,and more compact flexible azo dye micropolarizers are attractive candidates for low-cost,simple polarization imaging systems.The liquid crystal polymer[LCP],as an emerging material developed by photo-alignment technology,is a potential material for organizing the long-range ordered structure of azo dyes.However,little research has been done on LCP aligned azo dyes.This paper points out and solves a key problem that restricts the fabrication of high-precision arrays in vip[azo dye]-host[LCP]systems:the doping of dyes leads to disorder of the LCP during curing.After solving the problem,the relationship between the thickness of the LCP and the extinction ratio of the polarizing film was investigated,which effectively improved the extinction ratio.Alignment of azo dye molecules in the range of 2μm[0°-180°]and arrays of micropolarizers[0°,45°,90°,-45°]with 8μm×8μm pixel pitch was achieved by laser direct writing technology.The bending cycle test demonstrates the mechanical stability of the ultrathin flexible polarizer.The flexible patterned polarizer with robust chemical and mechanical stabilities provides a flexible way to capture the polarization of the light and highly integrated advanced flexible optoelectronic devices.
