Optical polarizers,which allow the transmission of specific polarization states,are essential components in modern optical systems.Here,we experimentally demonstrate integrated photonic polarizers incorporating reduce...Optical polarizers,which allow the transmission of specific polarization states,are essential components in modern optical systems.Here,we experimentally demonstrate integrated photonic polarizers incorporating reduced graphene oxide(rGO)films.2D graphene oxide(GO)films are integrated onto silicon waveguides and microring resonators(MRRs)with precise control over their thicknesses and sizes,followed by GO reduction via two different methods including uniform thermal reduction and localized photothermal reduction.We measure devices with various lengths,thicknesses,and reduction degrees of GO films.The results show that the devices with rGO exhibit better performance than those with GO,achieving a polarization-dependent loss of~47 dB and a polarization extinction ratio of~16 dB for the hybrid waveguides and MRRs with rGO,respectively.By fitting the experimental results with theory,it is found that rGO exhibits more significant anisotropy in loss,with an anisotropy ratio over 4 times that of GO.In addition,rGO shows higher thermal stability and greater robustness to photothermal reduction than GO.These results highlight the strong potential of rGO films for implementing high-performance polarization selective devices in integrated photonic platforms.展开更多
The integrated waveguide polarizer is essential for photonic integrated circuits,and various designs of waveguide polarizers have been developed.As the demand for dense photonic integration increases rapidly,new strat...The integrated waveguide polarizer is essential for photonic integrated circuits,and various designs of waveguide polarizers have been developed.As the demand for dense photonic integration increases rapidly,new strategies to minimize the device size are needed.In this paper,we have inversely designed an integrated transverse electric pass(TE-pass)polarizer with a footprint of 2.88μm×2.88μm,which is the smallest footprint ever achieved.A direct binary search algorithm is used to inversely design the device for maximizing the transverse electric(TE)transmission while minimizing transverse magnetic(TM)transmission.Finally,the inverse-designed device provides an average insertion loss of 0.99 dB and an average extinction ratio of 33 dB over a wavelength range of 100 nm.展开更多
Optical metasurfaces,which consist of subwavelength scale meta-atoms,represent a novel platform to manipulate the polarization and phase of light.The optical performance of metasurfaces heavily relies on the quality o...Optical metasurfaces,which consist of subwavelength scale meta-atoms,represent a novel platform to manipulate the polarization and phase of light.The optical performance of metasurfaces heavily relies on the quality of nanofabrication.Retrieving the Jones matrix of an imperfect metasurface optical element is highly desirable.We show that this can be realized by decomposing the generalized Jones matrix of a meta-atom into two parallel ones,which correspond to the ideal matrix and a phase retardation.To experimentally verify this concept,we designed and fabricated metasurface polarizers,which consist of geometric phase-controlled dielectric meta-atoms.By scanning the polarization states of the incident and transmitted light,we are able to extract the coefficients of the two parallel matrices of a metasurface polarizer.Based on the results of the Jones matrix decomposition,we also demonstrated polarization image encryption and spin-selective optical holography.The proposed Jones matrix retrieval protocol may have important applications in computational imaging,optical computing,optical communications,and so on.展开更多
Polarimetric imaging enhances the ability to distinguish objects from a bright background by detecting their particular polarization status,which offers another degree of freedom in infrared remote sensing.However,to ...Polarimetric imaging enhances the ability to distinguish objects from a bright background by detecting their particular polarization status,which offers another degree of freedom in infrared remote sensing.However,to scale up by monolithically integrating grating-based polarizers onto a focal plane array(FPA)of infrared detectors,fundamental technical obstacles must be overcome,including reductions of the extinction ratio by the misalignment between the polarizer and the detector,grating line width fluctuations,the line edge roughness,etc.This paper reports the authors’latest achievements in overcoming those problems by solving key technical issues regarding the integration of large-scale polarizers onto the chips of FPAs with individual indium gallium arsenide/indium phosphide(In Ga As/In P)sensors as the basic building blocks.Polarimetric and photovoltaic chips with divisions of the focal plane of 540×4 pixels and 320×256 superpixels have been successfully manufactured.Polarimetric imaging with enhanced contrast has been demonstrated.The progress made in this work has opened up a broad avenue toward industrialization of high quality polarimetric imaging in infrared wavelengths.展开更多
A TM-pass polarizer based on multilayer graphene polymer waveguide is proposed and theoretically analyzed.The mode properties,the extinction ratio,the insertion loss and the bandwidth are also discussed.The results sh...A TM-pass polarizer based on multilayer graphene polymer waveguide is proposed and theoretically analyzed.The mode properties,the extinction ratio,the insertion loss and the bandwidth are also discussed.The results show that a TM-pass polarizer,which only guides the TM mode,can be achieved by multilayer graphene polymer waveguide.With length of 150μm,the proposed polarizer can achieve extinction ratio of 33 dB and insertion loss of 0.5 d B at optical wavelength of 1.55μm.This device has an excellent performance,including large extinction ratio and low insertion loss within the spectral range from 1.45μm to 1.6μm.展开更多
An indium tin oxide(ITO) and silicon nitride(Si_(3)N_(4)) assisted compact TE-pass waveguide polarizer based on lithiumniobate-on-insulator is proposed and numerically analyzed.By properly designing the ITO and Si_(3)...An indium tin oxide(ITO) and silicon nitride(Si_(3)N_(4)) assisted compact TE-pass waveguide polarizer based on lithiumniobate-on-insulator is proposed and numerically analyzed.By properly designing the ITO and Si_(3)N_(4) assisted structure and utilizing the epsilon-near-zero effect of ITO,the TM mode is strongly confined in the ITO layer with extremely high loss,while the TE mode is hardly affected and passes through the waveguide with low loss.The simulation results show that the polarizer has an extinction ratio of 22.5 dB and an insertion loss of 0.8 dB at the wavelength of 1.55 μm,and has an operating bandwidth of about 125 nm(from 1540 nm to 1665 nm) for an extinction ratio of>20 dB and an insertion loss of<0.95 dB.Moreover,the proposed device exhibits large fabrication tolerances.More notably,the device is compact,with a length of only 7.5 μm,and is appropriate for on-chip applications.展开更多
In this paper, we propose an ellipsometer using a phase retarder and rotating polarizer and analyzer at a speed ratio I：N. Different ellipsometric configurations are presented by assuming N = 1, 2, and 3. Moreover, t...In this paper, we propose an ellipsometer using a phase retarder and rotating polarizer and analyzer at a speed ratio I：N. Different ellipsometric configurations are presented by assuming N = 1, 2, and 3. Moreover, two values of the offset angle of the retarder are considered for each ellipsometric configuration. The Mueller formalism is employed to extract the Stokes parameters, from which the intensity received by the detector is obtained. The optical properties of c-Si are calculated using all configurations. A comparison between different configurations is carried out considering the effect of the noise on the results and the uncertainties in the ellipsometric parameters as functions of the uncertainties of the Fourier coefficients. It is found that the alignment of the phase retarder has a crucial impact on the results and the ellipsometric configuration with speed ratio 1：1 is preferred over the other configurations.展开更多
We theoretically and numerically demonstrate that a transmission-type electrically tunable polarizer can be realized by using graphene ribbons supported on a dielectric film with a graphene sheet behind. The polarizat...We theoretically and numerically demonstrate that a transmission-type electrically tunable polarizer can be realized by using graphene ribbons supported on a dielectric film with a graphene sheet behind. The polarization mechanism originates from the antenna plasmon resonance of graphene stripes. The results of full-wave numerical simulations reveal that transmittance of 0.70 for one polarization and 0.0073 for another polarization can be obtained at normal incidence. The transmission-type electrically tunable polarizer provides and facilitates a variety of applications, including filtering, detecting, and imaging.展开更多
Nanodiamond(ND)polarizer can be used for dynamic nuclear polarization(DNP),owing to unpaired electrons provided by surface defects.However,^(1)H enhancement via Overhauser DNP(ODNP)using ND in-situ liquid has been fou...Nanodiamond(ND)polarizer can be used for dynamic nuclear polarization(DNP),owing to unpaired electrons provided by surface defects.However,^(1)H enhancement via Overhauser DNP(ODNP)using ND in-situ liquid has been found much smaller than traditional radicals.Herein,we study the surface properties of ND using electron spin resonance(ESR)and Raman methods firstly.Then the enhancement of^(1)H ODNP is explored using ND as polarizer with different nanoparticle sizes and concentrations at home-built 0.06 T DNP spectrometer.The surface of ND with the size of 30 nm is further modification via high temperature air oxidized and the enhancement was measured.The results show that nanoparticle sizes and Raman peak intensity ratio of sp^(2)/sp^(3)hybridization are approximate negative correlation and positive correlation to enhancement,respectively.Furthermore,there is no significant enhancement in the oxidation group,and a−22.5-fold^(1)H ODNP enhancement is achieved in-situ liquid at room temperature,which demonstrate the ND can be used as an efficient enhancer.We expect ND to play a greater role in biomedical research,especially for multimodal imaging with improving the performance of ND surface.展开更多
This paper deals with a systematical analysis and an algorithm of attenuation characteristics of a light attenuator combined by n pieces of polarizers （n-LACP） whose extinction ratios are different from each other. ...This paper deals with a systematical analysis and an algorithm of attenuation characteristics of a light attenuator combined by n pieces of polarizers （n-LACP） whose extinction ratios are different from each other. The attenuation ratio expression of a two-LACP is deduced. We find that the monotonic attenuation interval depends on the first polarizer and that the attenuation range depends on the second one. For the three-LACP, a method for obtaining a monotonic attenuation interval is proposed. Moreover, the attenuation ratio expression is demonstrated. Analysis and experiment show that when the initial status of the three-LACP is at the maximum output, if the second or third polarizer rotates alone, the minimum attenuation ratios can reach K2^-1 and K3^-1, respectively, and if the first polarizer rotates, a minimum attenuation ratio of K2^-1K3^-1 can be obtained （K1, K2 and K3 represent the extinction ratios of the three polarizers in turn）. Furthermore, the attenuation ratio expression of n-LACP and the relevant attenuation characteristics are proposed. The minimum attenuation ratio of an n-LACP is （K2K3 ... Kn）-1.展开更多
Theoretical calculation and experimental results for a polarizer with sinusoidal grooves used in the electron cyclotron resonance heating （ECRH） system of the HL-2A tokamak are presented. The calculation is based on...Theoretical calculation and experimental results for a polarizer with sinusoidal grooves used in the electron cyclotron resonance heating （ECRH） system of the HL-2A tokamak are presented. The calculation is based on an integral method developed in the vector theory of diffraction gratings, and the polarization characteristics obtained with a low-power test are in good agreement with the numerical calculated results. With the polarizer assembled in a miter bend in the ECRH transmission line, pure ordinary mode （O-mode） and extraordinary mode （X-mode） polarized waves are also expected in the high-power experiment, depending on the polarizer rotation angle and the toroidal injection angle of the electron cyclotron （EC） wave beam. Second-harmonic X-mode experiments were successfully explored in HL-2A. Experimental result revealed that the electron temperature increased from 0.8 keV （Ohmic heating phase） to 1.5 keV （second X-mode heating phase）.展开更多
We demonstrate theoretically that two-dimensional photonic bandgap materials are indeed perfect polarizers provided that they have a proper photonic band structure along the incident direction of light.This kind of po...We demonstrate theoretically that two-dimensional photonic bandgap materials are indeed perfect polarizers provided that they have a proper photonic band structure along the incident direction of light.This kind of polarizer is fundamentally different from the conventional ones.It can function in a wide frequency range with high performance and its size can be made very compact,which renders it useful as a micropolarizer in micro-optics.展开更多
A multi-band circular polarizer using a twisted triple split-ring resonator（TSRR） is presented and studied numerically and experimentally. At four distinct resonant frequencies, the incident linearly polarized wave ...A multi-band circular polarizer using a twisted triple split-ring resonator（TSRR） is presented and studied numerically and experimentally. At four distinct resonant frequencies, the incident linearly polarized wave can be transformed into left/right-handed circularly polarized waves. Numerical simulation results show that a y-polarized wave can be converted into a right-handed circularly polarized wave at 5.738 GHz and 9.218 GHz, while a left-handed circularly polarized wave is produced at 7.292 GHz and 10.118 GHz. The experimental results are in agreement with the numerical results. The surface current distributions are investigated to illustrate the polarization transformation mechanism. Furthermore, the influences of the structure parameters of the circular polarizer on transmission spectra are discussed as well.展开更多
With the purpose of designing the extreme ultraviolet polarizer with many objectives,a combined application of multiobjective genetic algorithms is theoretically proposed.Owing to the multi-objective genetic algorithm...With the purpose of designing the extreme ultraviolet polarizer with many objectives,a combined application of multiobjective genetic algorithms is theoretically proposed.Owing to the multi-objective genetic algorithm,the relationships between different designing objectives of extreme ultraviolet polarizer have been obtained by analyzing the distribution of nondominated solutions in the four-dimensional objective space,and the optimized multilayer design can be obtained by guiding the searching in the desired region based on the multi-objective genetic algorithm with reference direction.Compared with the conventional method of multilayer design,our method has a higher probability of achieving the optimal multilayer design.Our work should be the first research in optimizing the optical multilayer designs in the high-dimensional objective space,and our results demonstrate a potential application of our method in the designs of optical thin films.展开更多
An in-line high efficient polarizer, composed of magnetic-ionic-liquid-adorned(MIL-adorned) hollow-core anti-resonant fiber(HARF), is theoretically proposed and experimentally demonstrated. The protocol is based on th...An in-line high efficient polarizer, composed of magnetic-ionic-liquid-adorned(MIL-adorned) hollow-core anti-resonant fiber(HARF), is theoretically proposed and experimentally demonstrated. The protocol is based on the selective conversion of polarization mode into leaky mode and attenuates quickly in MIL and the polarizer is featured by the magnetically tunable polarization extinction ratio(PER) and the thermally controllable operation bandwidth.展开更多
In this paper, we propose an instantaneous phase-stepping method for determining phase distribution of interference fringes utilizing a camera that is equipped with a micro-polarizer array on the sensor plane. An opti...In this paper, we propose an instantaneous phase-stepping method for determining phase distribution of interference fringes utilizing a camera that is equipped with a micro-polarizer array on the sensor plane. An optical setup of polarization interferometry using a Mach-Zehnder interferometer with two polarizers is constructed. Light emerging from the interferometer is recorded using a camera that has a micro-polarizer array. This micro-polarizer array has four different optical axes. That is, an image obtained by the camera contains four types of information corresponding to four different optical axes of the polarizer. The four images separated from the image recorded by the camera are reconstructed using gray level interpolation. Subsequently, the distributions of the Stokes parameters that represent the state of polarization are calculated from the four images. The phase distribution of the interference fringe pattern produced by the Mach-Zehnder interferometer is then obtained from these Stokes parameters, The effectiveness of the proposed method is demonstrated by measuring a static carrier pattern and time-variant fringe patterns. It is emphasized that this method is applicable to time-variant phenomena because multiple exposures are unnecessary for sufficient data acquisition in the completion of the phase analysis.展开更多
In this paper we propose theoretically a set of ellipsometric configurations using a rotating polarizer, compensator, and analyzer at a speed ratio of N1ω：N2ω：N3ω. Different ellipsometric configurations can be ob...In this paper we propose theoretically a set of ellipsometric configurations using a rotating polarizer, compensator, and analyzer at a speed ratio of N1ω：N2ω：N3ω. Different ellipsometric configurations can be obtained by giving different integral values to N1, N2, and N3. All configurations are applied to bulk c-Si and GaAs to calculate the real and imaginary parts of the refractive index of the samples. The accuracies of all ellipsometric configurations are investigated in the presence of a hypothetical noise and with small misalignments of the optical elements. Moreover, the uncertainties in the ellipsometric parameters as functions of the uncertainties of the Fourier coefficients are studied. The comparison among different configurations reveals that the rotating compensator–analyzer configuration corresponds to the minimum error in the calculated optical parameters.展开更多
We report depolarizers made of a new kind of scattering depolarization material,named chalcedony,which can make the polarization directions of the photons in the linearly polarized incident light randomly distributed....We report depolarizers made of a new kind of scattering depolarization material,named chalcedony,which can make the polarization directions of the photons in the linearly polarized incident light randomly distributed.With a piece of the chalcedony to a thickness of 3mmf a total transmission higher than 50%and the linear polarization degree tending to zero can be easily obtained.展开更多
An FSS based circular polarizer for high-speed wireless communication at 75 GHz is presented. It has been designed on a low loss substrate with cross-dipole elements. Both simulation and measured results showed more t...An FSS based circular polarizer for high-speed wireless communication at 75 GHz is presented. It has been designed on a low loss substrate with cross-dipole elements. Both simulation and measured results showed more than 98% circular polarization at 75 GHz. Moreover, 3 dB axial-ratio bandwidth of 6.8 GHz (Simulation) and 7.8 GHz (Measured) has been achieved. The proposed design has many advantages over the recently published research such as simplicity, low-profile, percentage bandwidth, frequency of operation and relative insertion loss.展开更多
Herein,we fabricate a well-patterned semiconductor ripple structure via confined Couette flow of a quantum dot solution between two glass slides.This method is broadly applicable to diverse colloidal quantum dots,incl...Herein,we fabricate a well-patterned semiconductor ripple structure via confined Couette flow of a quantum dot solution between two glass slides.This method is broadly applicable to diverse colloidal quantum dots,including environmentally friendly CuIn_(x)Ga_(1-x)S_(2),InP,and ZnSe nanocrystals.The resulting ripple structure demonstrates strong linear dichroism and polarization capabilities for lasers across a broad wavelength range(445–635 nm).Our work offers a convenient,solution-processable strategy for fabricating semiconductor-based polarizer films.展开更多
基金supported by the Australian Research Council Centre of Excellence Project in Optical Microcombs for Breakthrough Science(No.CE230100006)the Australian Research Council Discovery Projects Programs(Nos.P190103186 and FT210100806)+4 种基金Linkage Program(Nos.LP210200345 and LP210100467)the Swinburne ECR-SUPRA program,the Industrial Transformation Training Centres scheme(No.IC180100005)the National Natural Science Foundation of China(No.12404375)the Beijing Natural Science Foundation(No.Z180007)the Innovation Program for Quantum Science and Technology(No.2021ZD0300703).
文摘Optical polarizers,which allow the transmission of specific polarization states,are essential components in modern optical systems.Here,we experimentally demonstrate integrated photonic polarizers incorporating reduced graphene oxide(rGO)films.2D graphene oxide(GO)films are integrated onto silicon waveguides and microring resonators(MRRs)with precise control over their thicknesses and sizes,followed by GO reduction via two different methods including uniform thermal reduction and localized photothermal reduction.We measure devices with various lengths,thicknesses,and reduction degrees of GO films.The results show that the devices with rGO exhibit better performance than those with GO,achieving a polarization-dependent loss of~47 dB and a polarization extinction ratio of~16 dB for the hybrid waveguides and MRRs with rGO,respectively.By fitting the experimental results with theory,it is found that rGO exhibits more significant anisotropy in loss,with an anisotropy ratio over 4 times that of GO.In addition,rGO shows higher thermal stability and greater robustness to photothermal reduction than GO.These results highlight the strong potential of rGO films for implementing high-performance polarization selective devices in integrated photonic platforms.
基金supported by the National Natural Science Foundation of China(Nos.62175076,62105028,62475085)the Natural Science Foundation of Hubei Province of China(Nos.2024AFA016,2024AFB612)the Open Project Program of Hubei Optical Fundamental Research Center.
文摘The integrated waveguide polarizer is essential for photonic integrated circuits,and various designs of waveguide polarizers have been developed.As the demand for dense photonic integration increases rapidly,new strategies to minimize the device size are needed.In this paper,we have inversely designed an integrated transverse electric pass(TE-pass)polarizer with a footprint of 2.88μm×2.88μm,which is the smallest footprint ever achieved.A direct binary search algorithm is used to inversely design the device for maximizing the transverse electric(TE)transmission while minimizing transverse magnetic(TM)transmission.Finally,the inverse-designed device provides an average insertion loss of 0.99 dB and an average extinction ratio of 33 dB over a wavelength range of 100 nm.
基金supported by the National Key Technologies R&D Program of China (Grant No.2022YFA1404301)the Zhangjiang Laboratory,the National Natural Science Foundation of China (Grant Nos.91950114 and 12161141010)+2 种基金the Guangdong Provincial Innovation and Entrepreneurship Project (Grant No.2017ZT07C071)the Guangdong Provincial Key Laboratory Program (Grant No.2021B1212040001)the Natural Science Foundation of Shenzhen Innovation Commission (Grant No.JCYJ20200109140808088).
文摘Optical metasurfaces,which consist of subwavelength scale meta-atoms,represent a novel platform to manipulate the polarization and phase of light.The optical performance of metasurfaces heavily relies on the quality of nanofabrication.Retrieving the Jones matrix of an imperfect metasurface optical element is highly desirable.We show that this can be realized by decomposing the generalized Jones matrix of a meta-atom into two parallel ones,which correspond to the ideal matrix and a phase retardation.To experimentally verify this concept,we designed and fabricated metasurface polarizers,which consist of geometric phase-controlled dielectric meta-atoms.By scanning the polarization states of the incident and transmitted light,we are able to extract the coefficients of the two parallel matrices of a metasurface polarizer.Based on the results of the Jones matrix decomposition,we also demonstrated polarization image encryption and spin-selective optical holography.The proposed Jones matrix retrieval protocol may have important applications in computational imaging,optical computing,optical communications,and so on.
基金financially supported by the following projects:Open project of SITP(Project Number:IIMDKFJJ-18-09)National Natural Science Foundation of China(Project Number:61927820)+2 种基金The STCSM2019-11-20 funding(Project Number:19142202700)National Natural Science Foundation of China(Project Number:NSF No.U1732104)Zhejiang Lab’s International Talent Fund for Young Professionals。
文摘Polarimetric imaging enhances the ability to distinguish objects from a bright background by detecting their particular polarization status,which offers another degree of freedom in infrared remote sensing.However,to scale up by monolithically integrating grating-based polarizers onto a focal plane array(FPA)of infrared detectors,fundamental technical obstacles must be overcome,including reductions of the extinction ratio by the misalignment between the polarizer and the detector,grating line width fluctuations,the line edge roughness,etc.This paper reports the authors’latest achievements in overcoming those problems by solving key technical issues regarding the integration of large-scale polarizers onto the chips of FPAs with individual indium gallium arsenide/indium phosphide(In Ga As/In P)sensors as the basic building blocks.Polarimetric and photovoltaic chips with divisions of the focal plane of 540×4 pixels and 320×256 superpixels have been successfully manufactured.Polarimetric imaging with enhanced contrast has been demonstrated.The progress made in this work has opened up a broad avenue toward industrialization of high quality polarimetric imaging in infrared wavelengths.
基金supported by the National Natural Science Foundation of China(No.61405083)the Natural Science Foundation of Gansu Province of China(No.17JR5RA197)the Fundamental Research Funds for the Central Universities(No.LZU-JZH1931)
文摘A TM-pass polarizer based on multilayer graphene polymer waveguide is proposed and theoretically analyzed.The mode properties,the extinction ratio,the insertion loss and the bandwidth are also discussed.The results show that a TM-pass polarizer,which only guides the TM mode,can be achieved by multilayer graphene polymer waveguide.With length of 150μm,the proposed polarizer can achieve extinction ratio of 33 dB and insertion loss of 0.5 d B at optical wavelength of 1.55μm.This device has an excellent performance,including large extinction ratio and low insertion loss within the spectral range from 1.45μm to 1.6μm.
基金Project supported by the National Natural Science Foundation of China (Grant No. 61875148)。
文摘An indium tin oxide(ITO) and silicon nitride(Si_(3)N_(4)) assisted compact TE-pass waveguide polarizer based on lithiumniobate-on-insulator is proposed and numerically analyzed.By properly designing the ITO and Si_(3)N_(4) assisted structure and utilizing the epsilon-near-zero effect of ITO,the TM mode is strongly confined in the ITO layer with extremely high loss,while the TE mode is hardly affected and passes through the waveguide with low loss.The simulation results show that the polarizer has an extinction ratio of 22.5 dB and an insertion loss of 0.8 dB at the wavelength of 1.55 μm,and has an operating bandwidth of about 125 nm(from 1540 nm to 1665 nm) for an extinction ratio of>20 dB and an insertion loss of<0.95 dB.Moreover,the proposed device exhibits large fabrication tolerances.More notably,the device is compact,with a length of only 7.5 μm,and is appropriate for on-chip applications.
文摘In this paper, we propose an ellipsometer using a phase retarder and rotating polarizer and analyzer at a speed ratio I：N. Different ellipsometric configurations are presented by assuming N = 1, 2, and 3. Moreover, two values of the offset angle of the retarder are considered for each ellipsometric configuration. The Mueller formalism is employed to extract the Stokes parameters, from which the intensity received by the detector is obtained. The optical properties of c-Si are calculated using all configurations. A comparison between different configurations is carried out considering the effect of the noise on the results and the uncertainties in the ellipsometric parameters as functions of the uncertainties of the Fourier coefficients. It is found that the alignment of the phase retarder has a crucial impact on the results and the ellipsometric configuration with speed ratio 1：1 is preferred over the other configurations.
基金Supported by the National Basic Research Program of China under Grant No 2012CB933501the National Natural Science Foundation of China under Grant Nos 61177051,11304389,61404174 and 61205087
文摘We theoretically and numerically demonstrate that a transmission-type electrically tunable polarizer can be realized by using graphene ribbons supported on a dielectric film with a graphene sheet behind. The polarization mechanism originates from the antenna plasmon resonance of graphene stripes. The results of full-wave numerical simulations reveal that transmittance of 0.70 for one polarization and 0.0073 for another polarization can be obtained at normal incidence. The transmission-type electrically tunable polarizer provides and facilitates a variety of applications, including filtering, detecting, and imaging.
基金supported by the National key of R&D Program of China(No.2018YFC0115000)the National Major Scientific Research Equipment Development Project of China(No.81627901)+3 种基金the Chinese Academy of Sciences(Nos.YZ201677,YZ201551,KFJ-STS-QYZD-169)the National Natural Science Foundation of China(No.11575287,11705274)Major Scientific and Technological Innovation Project in Hubei(No.2019AAA023)Application Foundation Frontier Project of WuHan(No.2019020701011450).
文摘Nanodiamond(ND)polarizer can be used for dynamic nuclear polarization(DNP),owing to unpaired electrons provided by surface defects.However,^(1)H enhancement via Overhauser DNP(ODNP)using ND in-situ liquid has been found much smaller than traditional radicals.Herein,we study the surface properties of ND using electron spin resonance(ESR)and Raman methods firstly.Then the enhancement of^(1)H ODNP is explored using ND as polarizer with different nanoparticle sizes and concentrations at home-built 0.06 T DNP spectrometer.The surface of ND with the size of 30 nm is further modification via high temperature air oxidized and the enhancement was measured.The results show that nanoparticle sizes and Raman peak intensity ratio of sp^(2)/sp^(3)hybridization are approximate negative correlation and positive correlation to enhancement,respectively.Furthermore,there is no significant enhancement in the oxidation group,and a−22.5-fold^(1)H ODNP enhancement is achieved in-situ liquid at room temperature,which demonstrate the ND can be used as an efficient enhancer.We expect ND to play a greater role in biomedical research,especially for multimodal imaging with improving the performance of ND surface.
基金Project supported by the Technological Innovation Project of Air-to-Air Missile Institute of China (Grant No.5S85000FS)
文摘This paper deals with a systematical analysis and an algorithm of attenuation characteristics of a light attenuator combined by n pieces of polarizers （n-LACP） whose extinction ratios are different from each other. The attenuation ratio expression of a two-LACP is deduced. We find that the monotonic attenuation interval depends on the first polarizer and that the attenuation range depends on the second one. For the three-LACP, a method for obtaining a monotonic attenuation interval is proposed. Moreover, the attenuation ratio expression is demonstrated. Analysis and experiment show that when the initial status of the three-LACP is at the maximum output, if the second or third polarizer rotates alone, the minimum attenuation ratios can reach K2^-1 and K3^-1, respectively, and if the first polarizer rotates, a minimum attenuation ratio of K2^-1K3^-1 can be obtained （K1, K2 and K3 represent the extinction ratios of the three polarizers in turn）. Furthermore, the attenuation ratio expression of n-LACP and the relevant attenuation characteristics are proposed. The minimum attenuation ratio of an n-LACP is （K2K3 ... Kn）-1.
文摘Theoretical calculation and experimental results for a polarizer with sinusoidal grooves used in the electron cyclotron resonance heating （ECRH） system of the HL-2A tokamak are presented. The calculation is based on an integral method developed in the vector theory of diffraction gratings, and the polarization characteristics obtained with a low-power test are in good agreement with the numerical calculated results. With the polarizer assembled in a miter bend in the ECRH transmission line, pure ordinary mode （O-mode） and extraordinary mode （X-mode） polarized waves are also expected in the high-power experiment, depending on the polarizer rotation angle and the toroidal injection angle of the electron cyclotron （EC） wave beam. Second-harmonic X-mode experiments were successfully explored in HL-2A. Experimental result revealed that the electron temperature increased from 0.8 keV （Ohmic heating phase） to 1.5 keV （second X-mode heating phase）.
基金Supported in part by the National Natural Science Foundation of China under Grant No.69625609,Pandeng plan(Y-41)Shanghai Science and Technology Commission.
文摘We demonstrate theoretically that two-dimensional photonic bandgap materials are indeed perfect polarizers provided that they have a proper photonic band structure along the incident direction of light.This kind of polarizer is fundamentally different from the conventional ones.It can function in a wide frequency range with high performance and its size can be made very compact,which renders it useful as a micropolarizer in micro-optics.
基金Project supported by the National Natural Science Foundation of China(Grant No.41474117)the Special Funds for Development Scientific Research Unit Projects of Wuhan,China(Grant No.2013BJ004)
文摘A multi-band circular polarizer using a twisted triple split-ring resonator（TSRR） is presented and studied numerically and experimentally. At four distinct resonant frequencies, the incident linearly polarized wave can be transformed into left/right-handed circularly polarized waves. Numerical simulation results show that a y-polarized wave can be converted into a right-handed circularly polarized wave at 5.738 GHz and 9.218 GHz, while a left-handed circularly polarized wave is produced at 7.292 GHz and 10.118 GHz. The experimental results are in agreement with the numerical results. The surface current distributions are investigated to illustrate the polarization transformation mechanism. Furthermore, the influences of the structure parameters of the circular polarizer on transmission spectra are discussed as well.
基金the National Natural Science Foundation of China(Grant Nos.62175018,61905239,and 61974142)Jilin Scientific and Technological Development Plan,China(Grant Nos.20190201013JC and 20200401052GX)。
文摘With the purpose of designing the extreme ultraviolet polarizer with many objectives,a combined application of multiobjective genetic algorithms is theoretically proposed.Owing to the multi-objective genetic algorithm,the relationships between different designing objectives of extreme ultraviolet polarizer have been obtained by analyzing the distribution of nondominated solutions in the four-dimensional objective space,and the optimized multilayer design can be obtained by guiding the searching in the desired region based on the multi-objective genetic algorithm with reference direction.Compared with the conventional method of multilayer design,our method has a higher probability of achieving the optimal multilayer design.Our work should be the first research in optimizing the optical multilayer designs in the high-dimensional objective space,and our results demonstrate a potential application of our method in the designs of optical thin films.
基金This work has been supported by the Youth Innovation Fund of Tianjin Navigation Instruments Research Institute(No.QN-19-02-GX)。
文摘An in-line high efficient polarizer, composed of magnetic-ionic-liquid-adorned(MIL-adorned) hollow-core anti-resonant fiber(HARF), is theoretically proposed and experimentally demonstrated. The protocol is based on the selective conversion of polarization mode into leaky mode and attenuates quickly in MIL and the polarizer is featured by the magnetically tunable polarization extinction ratio(PER) and the thermally controllable operation bandwidth.
文摘In this paper, we propose an instantaneous phase-stepping method for determining phase distribution of interference fringes utilizing a camera that is equipped with a micro-polarizer array on the sensor plane. An optical setup of polarization interferometry using a Mach-Zehnder interferometer with two polarizers is constructed. Light emerging from the interferometer is recorded using a camera that has a micro-polarizer array. This micro-polarizer array has four different optical axes. That is, an image obtained by the camera contains four types of information corresponding to four different optical axes of the polarizer. The four images separated from the image recorded by the camera are reconstructed using gray level interpolation. Subsequently, the distributions of the Stokes parameters that represent the state of polarization are calculated from the four images. The phase distribution of the interference fringe pattern produced by the Mach-Zehnder interferometer is then obtained from these Stokes parameters, The effectiveness of the proposed method is demonstrated by measuring a static carrier pattern and time-variant fringe patterns. It is emphasized that this method is applicable to time-variant phenomena because multiple exposures are unnecessary for sufficient data acquisition in the completion of the phase analysis.
文摘In this paper we propose theoretically a set of ellipsometric configurations using a rotating polarizer, compensator, and analyzer at a speed ratio of N1ω：N2ω：N3ω. Different ellipsometric configurations can be obtained by giving different integral values to N1, N2, and N3. All configurations are applied to bulk c-Si and GaAs to calculate the real and imaginary parts of the refractive index of the samples. The accuracies of all ellipsometric configurations are investigated in the presence of a hypothetical noise and with small misalignments of the optical elements. Moreover, the uncertainties in the ellipsometric parameters as functions of the uncertainties of the Fourier coefficients are studied. The comparison among different configurations reveals that the rotating compensator–analyzer configuration corresponds to the minimum error in the calculated optical parameters.
文摘We report depolarizers made of a new kind of scattering depolarization material,named chalcedony,which can make the polarization directions of the photons in the linearly polarized incident light randomly distributed.With a piece of the chalcedony to a thickness of 3mmf a total transmission higher than 50%and the linear polarization degree tending to zero can be easily obtained.
文摘An FSS based circular polarizer for high-speed wireless communication at 75 GHz is presented. It has been designed on a low loss substrate with cross-dipole elements. Both simulation and measured results showed more than 98% circular polarization at 75 GHz. Moreover, 3 dB axial-ratio bandwidth of 6.8 GHz (Simulation) and 7.8 GHz (Measured) has been achieved. The proposed design has many advantages over the recently published research such as simplicity, low-profile, percentage bandwidth, frequency of operation and relative insertion loss.
基金supported by the National Natural Science Foundation of China(Nos.52122308 and 22305224)the China Postdoctoral Science Foundation(No.2022TQ0290)+1 种基金the Ministry of Science and Technology of China(No.DL2023026004L)The Center of Advanced Analysis&Gene Sequencing,Zhengzhou University is also gratefully acknowledged.
文摘Herein,we fabricate a well-patterned semiconductor ripple structure via confined Couette flow of a quantum dot solution between two glass slides.This method is broadly applicable to diverse colloidal quantum dots,including environmentally friendly CuIn_(x)Ga_(1-x)S_(2),InP,and ZnSe nanocrystals.The resulting ripple structure demonstrates strong linear dichroism and polarization capabilities for lasers across a broad wavelength range(445–635 nm).Our work offers a convenient,solution-processable strategy for fabricating semiconductor-based polarizer films.
