The high mortality rates of colon and rectal tumors have put forward an urgent need for rapid, sensitive, and accurate diagnosis. The polarization imaging technology, with the advantages of noninvasiveness, noncontact...The high mortality rates of colon and rectal tumors have put forward an urgent need for rapid, sensitive, and accurate diagnosis. The polarization imaging technology, with the advantages of noninvasiveness, noncontact, quantification, rapidity, and high sensitivity, is expected to be used for auxiliary diagnosis of colorectal cancer. Herein, the differences in colorectal tissues of four pathological types were studied using this powerful technology. Polarized light imaging combined with the Mueller matrix decomposition (MMPD) method was applied to extract structural features that may be related to colorectal tumors. It demonstrated that parameters δ and θ could reflect the structural differences of colorectal tumors. Preliminary simulated experiment results revealed that the parameter δ was related to the fiber density, and the parameter θ was related to the fiber angle. Then Tamura image texture analysis was used to quantitatively describe tissues of different pathological types, and the results showed that the coarseness, contrast, directionality, and roughness of the four groups were statistically different. Texture analysis based on the quantitative data of the four dimensions could be applied for the identification of benign and malignant colorectal tumors.展开更多
OBJECTIVE:To evaluate the effects of external application of warm meridian medicated wine and polarized light therapy combined with acupuncture on pain management following vertebroplasty. METHODS:A total of 120 patie...OBJECTIVE:To evaluate the effects of external application of warm meridian medicated wine and polarized light therapy combined with acupuncture on pain management following vertebroplasty. METHODS:A total of 120 patients with osteoporotic vertebral compression fractures treated by vertebroplasty at our hospital were divided into four groups. The control group received non-steroidal anti-inflammatory drugs, the Treatment Group Ⅰ received acupuncture alone, Treatment Group Ⅱ was treated with medicated wine for warming meridians alongside polarized light physiotherapy, and Treatment Group Ⅲ received a combination of medicated wine for warming meridians, polarized light therapy, and acupuncture. The clinical efficacy, pain thresholds at various time points, temperature pain threshold, electric pain threshold, quality of life, sleep quality index, lumbar dysfunction index, visual analog scale(VAS) scores, and incidence of adverse reactions were compared and analyzed across the four groups. RESULTS:The total clinical effective rate in Treatment Group Ⅲ was significantly higher than that in the control group, Treatment Group Ⅰ, and Treatment Group Ⅱ(P < 0.05). At 24 and 72 h post-treatment, the VAS scores, temperature pain thresholds, and electric pain thresholds in Treatment Group Ⅲ were significantly lower than those in the control group, Treatment Group Ⅰ, and Treatment Group Ⅱ(P < 0.05). Additionally, quality-of-life scores in Treatment Group Ⅲ were markedly higher compared to the control group, Treatment Group Ⅰ, and Treatment Group Ⅱ, while the Pittsburgh Sleep Quality Index scores, Oswestry Disability Index scores, and incidence of adverse reactions in Treatment Group Ⅲ were significantly lower than in the other groups(P < 0.05). CONCLUSION:The external application of warm meridian medicated wine and polarized light therapy combined with acupuncture significantly reduces postoperative pain following vertebroplasty, enhances lumbar function, and improves both sleep quality and overall quality of life for patients. This approach is recommended for clinical application.展开更多
Due to its broken out-of-plane symmetry,z-cut periodically poled lithium niobate(PPLN)has exhibited ultrahigh second-order optical nonlinearity.Precise quantification of the domain structure of z-cut PPLN plays a crit...Due to its broken out-of-plane symmetry,z-cut periodically poled lithium niobate(PPLN)has exhibited ultrahigh second-order optical nonlinearity.Precise quantification of the domain structure of z-cut PPLN plays a critical role during poling fabrication.To enhance the imaging detection efficiency of the domain structure in z-cut PPLN,we have developed a second-harmonic generation microscope system specifically designed to produce a longitudinal electric field in foci for the imaging domain inversion.We demonstrated that imaging using a longitudinal electric field can achieve a contrast ratio enhancement by a factor of 1.77,showing high imaging efficiency and making the proposed method suitable for in situ monitoring of the z-cut PPLN poling process.展开更多
Conventionally,the spatially structured light beams produced by metasurfaces primarily highlight the polarization modulation of the beams propagating along the optical axis or the beams'spatial transmission trajec...Conventionally,the spatially structured light beams produced by metasurfaces primarily highlight the polarization modulation of the beams propagating along the optical axis or the beams'spatial transmission trajectory.In particular,along the optical axis,the polarization state is either constant or varies continuously in each output plane.Here,we develop innovative spatially structured light beams with continually changing polarization along any arbitrary spatial transmission trajectories.With tri-layer metallic metasurfaces,the geometric characteristics of each layer structure can be adjusted to modulate the phase and polarization state of the incident terahertz(THz)wave.The beam will converge to the predefined trajectory along several paths to generate a Bessel-like beam with longitudinal polarization changes.We demonstrate the versatility of the approach by designing two THz-band structured light beams with varying polarization states along the spatial helical transmission trajectory.Continuous linear polarization changes and linear polarization to right circular polarization(RCP)and back to linear polarization changes are realized respectively.The experimental results are basically consistent with the simulated results.Our proposal for arbitrary trajectory structured light beams with longitudinally varying polarization offers a practical method for continuously regulating the characteristics of spatial structured light beams with non-axial transmission.This technique has potential uses in optical encryption,particle manipulation,and biomedical imaging.展开更多
For decades,chiral nanomaterials have been extensively studied because of their extraordinary properties.Chiral nanostructures have attracted a lot of interest because of their potential applications including biosens...For decades,chiral nanomaterials have been extensively studied because of their extraordinary properties.Chiral nanostructures have attracted a lot of interest because of their potential applications including biosensing,asymmetric catalysis,optical devices,and negative index materials.Circularly polarized light(CPL)is the most attractive source for chirality owing to its high availability,and now it has been used as a chiral source for the preparation of chiral matter.In this review,the recent progress in the field of CPL-enabled chiral nanomaterials is summarized.Firstly,the recent advancements in the fabrication of chiral materials using circularly polarized light are described,focusing on the unique strategies.Secondly,an overview of the potential applications of chiral nanomaterials driven by CPL is provided,with a particular emphasis on biosensing,catalysis,and phototherapy.Finally,a perspective on the challenges in the field of CPL-enabled chiral nanomaterials is given.展开更多
Circularly polarized light(CPL)has been given great attention because of its extensive application.While several devices for CPL detection have been studied,their performance is affected by the magnitude of photocurre...Circularly polarized light(CPL)has been given great attention because of its extensive application.While several devices for CPL detection have been studied,their performance is affected by the magnitude of photocurrent.In this paper,a self-powered photodetector based on hot electrons in chiral metamaterials is proposed and optimized.CPL can be distinguished by the direction of photocurrent without external bias owing to the interdigital electrodes with asymmetric chiral metamaterials.Distinguished by the direction of photocurrent,the device can easily detect the rotation direction of the CPL electric field,even if it only has a very weak responsivity.The responsivity of the proposed detector is near 1.9 mA/W at the wavelength of 1322 nm,which is enough to distinguish CPL.The detector we proposed has the potential for application in optical communication.展开更多
Based on the vector diffraction theory, a super-resolution longitudinally polarized optical needle with ultra-long depth of focus(DOF) is generated by tightly focusing a radially polarized beam that is modulated by a ...Based on the vector diffraction theory, a super-resolution longitudinally polarized optical needle with ultra-long depth of focus(DOF) is generated by tightly focusing a radially polarized beam that is modulated by a self-designed ternary hybrid(phase/amplitude) filter(THF). Both the phase and the amplitude patterns of THF are judiciously optimized by the versatile particle swarm optimization(PSO) searching algorithm. For the focusing configuration with a combination of a high numerical aperture(NA) and the optimized sine-shaped THFs, an optical needle with the full width at half maximum(FWHM) of 0.414λ and the DOF of 7.58λ is accessed, which corresponds to an aspect ratio of 18.3. The demonstrated longitudinally polarized super-resolution light needle with high aspect ratio opens up broad applications in high-density optical data storage, nano-photolithography, super-resolution imaging and high-efficiency particle trapping.展开更多
Sensory drive, the concept that sensory systems primarily evolve under the influence of environmen tal features and that animal signals are evolutionarily shaped and tuned by these previously existing sensory systems,...Sensory drive, the concept that sensory systems primarily evolve under the influence of environmen tal features and that animal signals are evolutionarily shaped and tuned by these previously existing sensory systems, has been thoroughly studied regarding visual signals across many animals. Much of this work has focused on spectral aspects of vision and signals. Here, I review work on polarized light signals of animals and relate these to what is known of polarization visual systems, polarized light aspects of visual scenes, and polarizationrelated behavior （e.g., orientation, habitatfinding, contrast enhancement）. Other than the broad patterns of scattered polarized light in the sky, most po larization in both terrestrial and aquatic environments results from either reflection or scattering in the horizontal plane. With overhead illumination, horizontal features such as the surfaces of many leaves or of air： water interfaces reflect horizontal polarization, and water scatters horizontally polar ized light under most conditions. Several animal species have been demonstrated to use horizontally polarized light fields or features in critical aspects of their biology. Significantly, most biological sig nals are also horizontally polarized. Here, I present relevant polarizationrelated behavior and discuss the hypothesis that sensory drive has evolutionarily influenced the structure of polarization signals. The paper also considers the evolutionary origin of circular polarization vision and circularly polar ized signals. It appears that this class of signals did not evolve under the influence of sensory drive. The study of signals based on polarized light is becoming a mature field of research.展开更多
In recent years, the bionic polarized light compass has been widely studied for the unmanned aerial vehicle navigation. However, it is found from the obtained investigation results that a polarized light compass with ...In recent years, the bionic polarized light compass has been widely studied for the unmanned aerial vehicle navigation. However, it is found from the obtained investigation results that a polarized light compass with a sensitive and high dynamic range polarimeter still provides inferior output precision of the heading angle due to the presence of the noise generating from the compass.The noise is existed not only in the angle of the polarization image acquired by polarimeters but also in the output heading data, which leads to a sharp reduction in the accuracy of a polarized light compass. Herein, we present noise analysis and a novel multiscale transform denoising method of a polarized light compass used for the unmanned aerial vehicle navigation. Specifically, a multiscale principle component analysis utilizing one-dimensional image entropy as classification criterion is directly implemented to suppress the noise in the acquired polarization image. Subsequently, a multiscale time–frequency peak filtering method using the sample entropy as classification criterion is applied for the output heading data so as to further increase the heading measurement accuracy from the denoised image above. These two approaches are combined to significantly reduce the heading error affected by different types of noises. Our experimental results indicate the proposed multiscale transform denoising method exhibits high performance in suppressing the noise of a polarized light compass used for the unmanned aerial vehicle navigation compared to existing prior arts.展开更多
We theoretically study the spin transport through a two-terminal quantum dot device under the influence of a symmetric spin bias and circularly polarized light. It is found that the combination of the circularly polar...We theoretically study the spin transport through a two-terminal quantum dot device under the influence of a symmetric spin bias and circularly polarized light. It is found that the combination of the circularly polarized light and the applied spin bias can result in a net charge current. The resultant charge current is large enough to be measured when properly choosing the system parameters. The resultant charge current can be used to deduce the spin bias due to the fact that there exists a simple linear relation between them. When the external circuit is open, a charge bias instead of a charge current can be induced, which is also measurable by present technologies. These findings indicate a new approach to detect the spin bias by using circularly polarized light.展开更多
It is shown that the deflection of star light passing by the Sun, which is allegedly explainable only by general relativity, can be understood quantitatively as a quasi-classical effect of light refraction in the vac...It is shown that the deflection of star light passing by the Sun, which is allegedly explainable only by general relativity, can be understood quantitatively as a quasi-classical effect of light refraction in the vacuum polarized by the Sun's gravitational field. The theory of the dielectric polarization of the vacuum proposed pre- viously is further developed for the corresponding effect of the polarization of the vacuum in a gravitational field. The resulting refractive index of the vacuum in the presence of a gravitational field gives for the deflection of light by the Sun an angle |0| = 1.77', which is in good agreement with the experimental observations and the result of general relativity. From the theory Presented, it can also be deduced that the velocity of a horizontal light beam at 1000 km above ground level of the Earth has a velocity deficit - c= 5.73 cm / s in comparison to the light velocity on the ground.展开更多
We investigate the propagation of polarized light in fibrous tissues such as muscle and skin.The myofibrils and collagen fibers are approximated as long cylinders and the tissue phantom is composed of spherical and cy...We investigate the propagation of polarized light in fibrous tissues such as muscle and skin.The myofibrils and collagen fibers are approximated as long cylinders and the tissue phantom is composed of spherical and cylindrical structures.We apply Monte Carlo method based on this phantom to simulate and analyze polarization imaging process of muscle.The good agreement between the simulation results and the experimental results validate the assumption of the phantom composition.This paper also presents how to describe the fiber orientation distribution and tissue anisotropy according to three parameters derived from the polarization imaging.展开更多
Circularly polarized light(CPL)is an inherently chiral entity and is regarded as one of the possible deterministic signals that led to the evolution of homochirality in earth.Thus,CPL as an external physical field has...Circularly polarized light(CPL)is an inherently chiral entity and is regarded as one of the possible deterministic signals that led to the evolution of homochirality in earth.Thus,CPL as an external physical field has been widely used in a technique known as absolute asymmetric synthesis,because a product enriched in one enantiomer is formed from racemic precursor molecules without the intervention of a chiral catalyst.In this review,we retrospect the historical research of CPL-induced absolute asymmetric synthesis,including chiral organic molecules,helical polymers,supramolecular assemblies,noble metal nanostructures.However,based on these results,we concluded that the chiral photon-matter interaction is very faint due to the arrangement of molecular bonds giving rise to chiral features,is over a smaller distance than the helical pitch of CPL,leading extremely small enantiomeric excess for product.Therefore,we highlight the recently emerged technology called superchiral field,in which the superchiral far-field and near-field could enhance the dissymmetry of optical field and near-field,respectively.In sum,we hope this review could bring some enlightenment to researchers and further improve the enantioselectivity of CPL-induced absolute asymmetric synthesis.展开更多
In this paper,two ways of micro structural characterization,optical microscopy(OM) and polarized light microscopy(PLM),were both employed to describe the micro structure of semisolid slurry prepared by swirling enthal...In this paper,two ways of micro structural characterization,optical microscopy(OM) and polarized light microscopy(PLM),were both employed to describe the micro structure of semisolid slurry prepared by swirling enthalpy equilibration device(SEED).The results show that PLM is more reliable and accurate than OM to describe the special morphology feature of semisolid slurry made by SEED process.Meanwhile,the effects of pouring temperature and mass of molten liquid on the primary α-Al particle size and morphology were also investigated using PLM.The quantitative metallographic results measured from PLM demonstrate that the grain size and morphology and their distribution are significantly affected by both pouring temperature and the mass of molten liquid.The grain size poured with 2.7 kg liquid decreases from 659 to186 μm,and grain morphology transforms from dendrite to globular structure with pouring temperature reducing from690 to 630℃.The decreasing pouring temperature also promotes the distribution of spherical structure on the cross section.Meanwhile,the mass of molten liquid decreasing from 2.7 to 2.3 kg can decrease the grain size by maximum of 44% at high pouring temperature.展开更多
This paper proposes an artificial neural network to determine orientation using polarized skylight. This neural network has specific dilated convolution, which can extract light intensity information of different pola...This paper proposes an artificial neural network to determine orientation using polarized skylight. This neural network has specific dilated convolution, which can extract light intensity information of different polarization directions. Then, the degree of polarization (DOP) and angle of polarization (AOP) are directly extracted in the network. In addition, the exponential function encoding of orientation is designed as the network output, which can better reflect the insect’s encoding of polarization information and improve the accuracy of orientation determination. Finally, training and testing were conducted on a public polarized skylight navigation dataset, and the experimental results proved the stability and effectiveness of the network.展开更多
The impact of the illumination with white linearly polarized light (WLPL) of two commercially available cellulases from Trichoderma reesei on their activity in hydrolysis of microcrystalline cellulose was studied. Enz...The impact of the illumination with white linearly polarized light (WLPL) of two commercially available cellulases from Trichoderma reesei on their activity in hydrolysis of microcrystalline cellulose was studied. Enzymes were illuminated with WLPL for 60 min and 120 min and for each native and illuminated enzyme sample specific activity and kinetics of enzyme catalyzed hydrolysis of microcrystalline cellulose were established. Molecular weight Mw and radii if gyration Rg of protein chains of native and illuminated enzymes were measured by means of high pressure size exclu-sion chromatography coupled with multiangle laser light scattering and refractometric detectors (HPSEC-MALLS-RI). Conformations of protein chains of native and illuminated enzymes were evaluated on the basis of their circular dichroism (CD) spectra. Additionally, molecular weight Mw and radii of gyration Rg of polysaccharide chains of microcrystalline cellulose native and digested for 10 min, 480 min and 1440 min with original and WLPL stimulated enzymes WT and TR were taken. Illumination with WLPL of both cellulases studied did not change secondary structures of protein molecules of native enzyme. Molecular weight Mw and radii of gyration Rg of illuminated enzymes differed greatly from those found for native enzymes. Illumination of enzymes led to increase of specific activity and rate constants of reaction of hydrolysis microcrystalline cellulose catalyzed by illuminated enzymes as compared with native enzymes.展开更多
2D Ruddlesden-Popper(RP)polar perovskite,displaying the intrinsic optical anisotropy and structural polarity,has a fantastic application perspective in self-powered polarized light detection.However,the weak van der W...2D Ruddlesden-Popper(RP)polar perovskite,displaying the intrinsic optical anisotropy and structural polarity,has a fantastic application perspective in self-powered polarized light detection.However,the weak van der Waals interaction between the organic spacing bilayers is insufficient to preserve the stability of RP-type materials.Hence,it is of great significance to explore new stable 2D RP-phase candidates.In this work,we have successfully constructed a highly-stable polar 2D perovskite,(t-ACH)_(2)PbI_(4)(1,where t-ACH^(+)is HOOC_(8)H_(12)NH_(3)^(+)),by adopting a hydrophobic carboxylate trans-isomer of tranexamic acid as the spacing component.Strikingly,strong O-H…O hydrogen bonds between t-ACH^(+)organic bilayers compose the dimer,thus decreasing van der Waals gap and enhancing structural stability.Besides,such orientational hydrogen bonds contribute to the formation of structural polarity and generate an obvious bulk photovoltaic effect in 1,which facilitates its self-powered photodetection.As predicted,the combination of inherent anisotropy and polarity leads to self-powered polarized-light detection with a high ratio of around∼5.3,superior to those of inorganic 2D counterparts.This work paves a potential way to design highly-stable 2D perovskites for high-performance optoelectronic devices.展开更多
The phase time of p-polarized light pulses passing through a glass plate is investigated. We do this by converting the problem into a l-dimensional quantum-mechanical counterpart, a potential well with a position-depe...The phase time of p-polarized light pulses passing through a glass plate is investigated. We do this by converting the problem into a l-dimensional quantum-mechanical counterpart, a potential well with a position-dependent effective mass. We find that the phase time and the lateral shift have the negative characteristics.展开更多
The paper studied the relationship between microstructure and shape recovery characteristics by using colored microstructure analysis under polarized light on the thermomechanical cycled CuAlNi single crystals. The tw...The paper studied the relationship between microstructure and shape recovery characteristics by using colored microstructure analysis under polarized light on the thermomechanical cycled CuAlNi single crystals. The two-way shape memory effect in quenched thin bar resulted from the preferential formation/extinction of martensite variant due to the internal quench stress, and the variant was formed at an angle of about 45 deg. with the tension direction ([001] of the βphase). Initial thermomechanical cycling under relatively low stress single variant stress-induced martensite was formed at an angle of 45 deg. with the tension and its morphology was a lath of parallel twins. More than one group of variants were formed after several training cycles and such variants also caused tilting of some thermally formed accommodated martensite. By overheating the trained sample containing stabilized multi-variants of stress-induced martensite, very coarse martensite structure with a strong asymmetry was produced, which caused the reverse two-way shape memory effect.展开更多
Digital structured light （SL） profilometry is increasingly used in three-dimensional （3D） measurement technology. However, the nonlinearity of the off-the-shelf projectors and cameras seriously reduces the measure...Digital structured light （SL） profilometry is increasingly used in three-dimensional （3D） measurement technology. However, the nonlinearity of the off-the-shelf projectors and cameras seriously reduces the measurement accuracy. In this paper, first, we review the nonlinear effects of the projector-camera system in the phase-shifting structured light depth measurement method. We show that high order harmonic wave components lead to phase error in the phase-shifting method. Then a practical method based on frequency domain filtering is proposed for nonlinear error reduction. By using this method, the nonlinear calibration of the SL system is not required. Moreover, both the nonlinear effects of the projector and the camera can be effectively reduced. The simulations and experiments have verified our nonlinear correction method.展开更多
文摘The high mortality rates of colon and rectal tumors have put forward an urgent need for rapid, sensitive, and accurate diagnosis. The polarization imaging technology, with the advantages of noninvasiveness, noncontact, quantification, rapidity, and high sensitivity, is expected to be used for auxiliary diagnosis of colorectal cancer. Herein, the differences in colorectal tissues of four pathological types were studied using this powerful technology. Polarized light imaging combined with the Mueller matrix decomposition (MMPD) method was applied to extract structural features that may be related to colorectal tumors. It demonstrated that parameters δ and θ could reflect the structural differences of colorectal tumors. Preliminary simulated experiment results revealed that the parameter δ was related to the fiber density, and the parameter θ was related to the fiber angle. Then Tamura image texture analysis was used to quantitatively describe tissues of different pathological types, and the results showed that the coarseness, contrast, directionality, and roughness of the four groups were statistically different. Texture analysis based on the quantitative data of the four dimensions could be applied for the identification of benign and malignant colorectal tumors.
文摘OBJECTIVE:To evaluate the effects of external application of warm meridian medicated wine and polarized light therapy combined with acupuncture on pain management following vertebroplasty. METHODS:A total of 120 patients with osteoporotic vertebral compression fractures treated by vertebroplasty at our hospital were divided into four groups. The control group received non-steroidal anti-inflammatory drugs, the Treatment Group Ⅰ received acupuncture alone, Treatment Group Ⅱ was treated with medicated wine for warming meridians alongside polarized light physiotherapy, and Treatment Group Ⅲ received a combination of medicated wine for warming meridians, polarized light therapy, and acupuncture. The clinical efficacy, pain thresholds at various time points, temperature pain threshold, electric pain threshold, quality of life, sleep quality index, lumbar dysfunction index, visual analog scale(VAS) scores, and incidence of adverse reactions were compared and analyzed across the four groups. RESULTS:The total clinical effective rate in Treatment Group Ⅲ was significantly higher than that in the control group, Treatment Group Ⅰ, and Treatment Group Ⅱ(P < 0.05). At 24 and 72 h post-treatment, the VAS scores, temperature pain thresholds, and electric pain thresholds in Treatment Group Ⅲ were significantly lower than those in the control group, Treatment Group Ⅰ, and Treatment Group Ⅱ(P < 0.05). Additionally, quality-of-life scores in Treatment Group Ⅲ were markedly higher compared to the control group, Treatment Group Ⅰ, and Treatment Group Ⅱ, while the Pittsburgh Sleep Quality Index scores, Oswestry Disability Index scores, and incidence of adverse reactions in Treatment Group Ⅲ were significantly lower than in the other groups(P < 0.05). CONCLUSION:The external application of warm meridian medicated wine and polarized light therapy combined with acupuncture significantly reduces postoperative pain following vertebroplasty, enhances lumbar function, and improves both sleep quality and overall quality of life for patients. This approach is recommended for clinical application.
基金supported by the National Key Research and Development Program of China(Grant Nos.2022YFC3401100 and 2022YFF0712500)the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030009)+2 种基金the National Natural Science Foundation of China(Grant Nos.12204017,12004012,12004013,12041602,91750203,91850111,and 92150301)the China Postdoctoral Science Foundation(Grant No.2020M680220 and 2020M680230)the Clinical Medicine Plus X-Young Scholars Project,Peking University,Fundamental Research Funds for the Central Universities.
文摘Due to its broken out-of-plane symmetry,z-cut periodically poled lithium niobate(PPLN)has exhibited ultrahigh second-order optical nonlinearity.Precise quantification of the domain structure of z-cut PPLN plays a critical role during poling fabrication.To enhance the imaging detection efficiency of the domain structure in z-cut PPLN,we have developed a second-harmonic generation microscope system specifically designed to produce a longitudinal electric field in foci for the imaging domain inversion.We demonstrated that imaging using a longitudinal electric field can achieve a contrast ratio enhancement by a factor of 1.77,showing high imaging efficiency and making the proposed method suitable for in situ monitoring of the z-cut PPLN poling process.
基金supported by the National Natural Science Foundation of China(Grant Nos.12074094 and 121774271)the Sino-German Mobility Program of the Sino-German Center for Science Funding(Grant No.M-0225)the Capacity Building for Science&Technology Innovation-Fundamental Scientific Research Funds(Grant No.00820531120017).
文摘Conventionally,the spatially structured light beams produced by metasurfaces primarily highlight the polarization modulation of the beams propagating along the optical axis or the beams'spatial transmission trajectory.In particular,along the optical axis,the polarization state is either constant or varies continuously in each output plane.Here,we develop innovative spatially structured light beams with continually changing polarization along any arbitrary spatial transmission trajectories.With tri-layer metallic metasurfaces,the geometric characteristics of each layer structure can be adjusted to modulate the phase and polarization state of the incident terahertz(THz)wave.The beam will converge to the predefined trajectory along several paths to generate a Bessel-like beam with longitudinal polarization changes.We demonstrate the versatility of the approach by designing two THz-band structured light beams with varying polarization states along the spatial helical transmission trajectory.Continuous linear polarization changes and linear polarization to right circular polarization(RCP)and back to linear polarization changes are realized respectively.The experimental results are basically consistent with the simulated results.Our proposal for arbitrary trajectory structured light beams with longitudinally varying polarization offers a practical method for continuously regulating the characteristics of spatial structured light beams with non-axial transmission.This technique has potential uses in optical encryption,particle manipulation,and biomedical imaging.
基金financially the National Natural Science Foundation of China(51902136)the Fundamental Research Funds for the Central Universities(JUSRP12003,JUSRP622026)Natural Science Foundation of Jiangsu Province(BK20211236)。
文摘For decades,chiral nanomaterials have been extensively studied because of their extraordinary properties.Chiral nanostructures have attracted a lot of interest because of their potential applications including biosensing,asymmetric catalysis,optical devices,and negative index materials.Circularly polarized light(CPL)is the most attractive source for chirality owing to its high availability,and now it has been used as a chiral source for the preparation of chiral matter.In this review,the recent progress in the field of CPL-enabled chiral nanomaterials is summarized.Firstly,the recent advancements in the fabrication of chiral materials using circularly polarized light are described,focusing on the unique strategies.Secondly,an overview of the potential applications of chiral nanomaterials driven by CPL is provided,with a particular emphasis on biosensing,catalysis,and phototherapy.Finally,a perspective on the challenges in the field of CPL-enabled chiral nanomaterials is given.
基金This work was supported by the National Natural Science Foundation of China(No.61705065)Hunan Provincial Natural Science Foundation of China(No.2017JJ3034)+1 种基金Technology Program of Changsha(No.kq1804001)National Training Program of Innovation and Entrepreneurship for undergraduates(No.S201910532166).
文摘Circularly polarized light(CPL)has been given great attention because of its extensive application.While several devices for CPL detection have been studied,their performance is affected by the magnitude of photocurrent.In this paper,a self-powered photodetector based on hot electrons in chiral metamaterials is proposed and optimized.CPL can be distinguished by the direction of photocurrent without external bias owing to the interdigital electrodes with asymmetric chiral metamaterials.Distinguished by the direction of photocurrent,the device can easily detect the rotation direction of the CPL electric field,even if it only has a very weak responsivity.The responsivity of the proposed detector is near 1.9 mA/W at the wavelength of 1322 nm,which is enough to distinguish CPL.The detector we proposed has the potential for application in optical communication.
基金supported by the National Natural Science Foundation of China(Nos.61575139,61605136,51602213 and 11604236)the Youth Foundation of the Taiyuan University of Technology(No.2015QN066)
文摘Based on the vector diffraction theory, a super-resolution longitudinally polarized optical needle with ultra-long depth of focus(DOF) is generated by tightly focusing a radially polarized beam that is modulated by a self-designed ternary hybrid(phase/amplitude) filter(THF). Both the phase and the amplitude patterns of THF are judiciously optimized by the versatile particle swarm optimization(PSO) searching algorithm. For the focusing configuration with a combination of a high numerical aperture(NA) and the optimized sine-shaped THFs, an optical needle with the full width at half maximum(FWHM) of 0.414λ and the DOF of 7.58λ is accessed, which corresponds to an aspect ratio of 18.3. The demonstrated longitudinally polarized super-resolution light needle with high aspect ratio opens up broad applications in high-density optical data storage, nano-photolithography, super-resolution imaging and high-efficiency particle trapping.
文摘Sensory drive, the concept that sensory systems primarily evolve under the influence of environmen tal features and that animal signals are evolutionarily shaped and tuned by these previously existing sensory systems, has been thoroughly studied regarding visual signals across many animals. Much of this work has focused on spectral aspects of vision and signals. Here, I review work on polarized light signals of animals and relate these to what is known of polarization visual systems, polarized light aspects of visual scenes, and polarizationrelated behavior （e.g., orientation, habitatfinding, contrast enhancement）. Other than the broad patterns of scattered polarized light in the sky, most po larization in both terrestrial and aquatic environments results from either reflection or scattering in the horizontal plane. With overhead illumination, horizontal features such as the surfaces of many leaves or of air： water interfaces reflect horizontal polarization, and water scatters horizontally polar ized light under most conditions. Several animal species have been demonstrated to use horizontally polarized light fields or features in critical aspects of their biology. Significantly, most biological sig nals are also horizontally polarized. Here, I present relevant polarizationrelated behavior and discuss the hypothesis that sensory drive has evolutionarily influenced the structure of polarization signals. The paper also considers the evolutionary origin of circular polarization vision and circularly polar ized signals. It appears that this class of signals did not evolve under the influence of sensory drive. The study of signals based on polarized light is becoming a mature field of research.
基金co-supported by the National Natural Science Foundation of China(No.61973281)The Innovative Research Group Project of National Natural Science Foundation of China(No.51821003)+4 种基金the Aeronautical Science Foundation of China(No.2018ZCU0002)the Program for the Top Young Academic Leaders of Higher Learning Institutions of ShanxiShanxi Postgraduate Innovation Project,China(No.2020BY102)the Young Academic Leaders Foundation in North University of Chinathe Fund for Shanxi‘‘1331 Project”Key Subjects Construction。
文摘In recent years, the bionic polarized light compass has been widely studied for the unmanned aerial vehicle navigation. However, it is found from the obtained investigation results that a polarized light compass with a sensitive and high dynamic range polarimeter still provides inferior output precision of the heading angle due to the presence of the noise generating from the compass.The noise is existed not only in the angle of the polarization image acquired by polarimeters but also in the output heading data, which leads to a sharp reduction in the accuracy of a polarized light compass. Herein, we present noise analysis and a novel multiscale transform denoising method of a polarized light compass used for the unmanned aerial vehicle navigation. Specifically, a multiscale principle component analysis utilizing one-dimensional image entropy as classification criterion is directly implemented to suppress the noise in the acquired polarization image. Subsequently, a multiscale time–frequency peak filtering method using the sample entropy as classification criterion is applied for the output heading data so as to further increase the heading measurement accuracy from the denoised image above. These two approaches are combined to significantly reduce the heading error affected by different types of noises. Our experimental results indicate the proposed multiscale transform denoising method exhibits high performance in suppressing the noise of a polarized light compass used for the unmanned aerial vehicle navigation compared to existing prior arts.
基金Supported by the National Natural Science Foundation of China under Grant No 11404142the Youth Teacher Foundation of Huaiyin Institute of Technology under Grant No 2717577
文摘We theoretically study the spin transport through a two-terminal quantum dot device under the influence of a symmetric spin bias and circularly polarized light. It is found that the combination of the circularly polarized light and the applied spin bias can result in a net charge current. The resultant charge current is large enough to be measured when properly choosing the system parameters. The resultant charge current can be used to deduce the spin bias due to the fact that there exists a simple linear relation between them. When the external circuit is open, a charge bias instead of a charge current can be induced, which is also measurable by present technologies. These findings indicate a new approach to detect the spin bias by using circularly polarized light.
文摘It is shown that the deflection of star light passing by the Sun, which is allegedly explainable only by general relativity, can be understood quantitatively as a quasi-classical effect of light refraction in the vacuum polarized by the Sun's gravitational field. The theory of the dielectric polarization of the vacuum proposed pre- viously is further developed for the corresponding effect of the polarization of the vacuum in a gravitational field. The resulting refractive index of the vacuum in the presence of a gravitational field gives for the deflection of light by the Sun an angle |0| = 1.77', which is in good agreement with the experimental observations and the result of general relativity. From the theory Presented, it can also be deduced that the velocity of a horizontal light beam at 1000 km above ground level of the Earth has a velocity deficit - c= 5.73 cm / s in comparison to the light velocity on the ground.
基金National Natural Science Foundation of China(Grant 60578003)Ministry of Science and Technology(Grant 2006CB70570),China.
文摘We investigate the propagation of polarized light in fibrous tissues such as muscle and skin.The myofibrils and collagen fibers are approximated as long cylinders and the tissue phantom is composed of spherical and cylindrical structures.We apply Monte Carlo method based on this phantom to simulate and analyze polarization imaging process of muscle.The good agreement between the simulation results and the experimental results validate the assumption of the phantom composition.This paper also presents how to describe the fiber orientation distribution and tissue anisotropy according to three parameters derived from the polarization imaging.
基金the support of Academic promotion program of Shandong First Medical University(No.2019LJ003)。
文摘Circularly polarized light(CPL)is an inherently chiral entity and is regarded as one of the possible deterministic signals that led to the evolution of homochirality in earth.Thus,CPL as an external physical field has been widely used in a technique known as absolute asymmetric synthesis,because a product enriched in one enantiomer is formed from racemic precursor molecules without the intervention of a chiral catalyst.In this review,we retrospect the historical research of CPL-induced absolute asymmetric synthesis,including chiral organic molecules,helical polymers,supramolecular assemblies,noble metal nanostructures.However,based on these results,we concluded that the chiral photon-matter interaction is very faint due to the arrangement of molecular bonds giving rise to chiral features,is over a smaller distance than the helical pitch of CPL,leading extremely small enantiomeric excess for product.Therefore,we highlight the recently emerged technology called superchiral field,in which the superchiral far-field and near-field could enhance the dissymmetry of optical field and near-field,respectively.In sum,we hope this review could bring some enlightenment to researchers and further improve the enantioselectivity of CPL-induced absolute asymmetric synthesis.
基金financially supported by the National Key Research and Development Program of China (No. 2016YFB0301003)the Shenzhen Free Exploring Basic Research Project (No. JCYJ20170307110223452)。
文摘In this paper,two ways of micro structural characterization,optical microscopy(OM) and polarized light microscopy(PLM),were both employed to describe the micro structure of semisolid slurry prepared by swirling enthalpy equilibration device(SEED).The results show that PLM is more reliable and accurate than OM to describe the special morphology feature of semisolid slurry made by SEED process.Meanwhile,the effects of pouring temperature and mass of molten liquid on the primary α-Al particle size and morphology were also investigated using PLM.The quantitative metallographic results measured from PLM demonstrate that the grain size and morphology and their distribution are significantly affected by both pouring temperature and the mass of molten liquid.The grain size poured with 2.7 kg liquid decreases from 659 to186 μm,and grain morphology transforms from dendrite to globular structure with pouring temperature reducing from690 to 630℃.The decreasing pouring temperature also promotes the distribution of spherical structure on the cross section.Meanwhile,the mass of molten liquid decreasing from 2.7 to 2.3 kg can decrease the grain size by maximum of 44% at high pouring temperature.
基金Funding was provided by the National Key Research and Development Program of China(Grant No.2021ZD0200300)National Natural Science Foundation of China(NSFC)(U2031138).
文摘This paper proposes an artificial neural network to determine orientation using polarized skylight. This neural network has specific dilated convolution, which can extract light intensity information of different polarization directions. Then, the degree of polarization (DOP) and angle of polarization (AOP) are directly extracted in the network. In addition, the exponential function encoding of orientation is designed as the network output, which can better reflect the insect’s encoding of polarization information and improve the accuracy of orientation determination. Finally, training and testing were conducted on a public polarized skylight navigation dataset, and the experimental results proved the stability and effectiveness of the network.
文摘The impact of the illumination with white linearly polarized light (WLPL) of two commercially available cellulases from Trichoderma reesei on their activity in hydrolysis of microcrystalline cellulose was studied. Enzymes were illuminated with WLPL for 60 min and 120 min and for each native and illuminated enzyme sample specific activity and kinetics of enzyme catalyzed hydrolysis of microcrystalline cellulose were established. Molecular weight Mw and radii if gyration Rg of protein chains of native and illuminated enzymes were measured by means of high pressure size exclu-sion chromatography coupled with multiangle laser light scattering and refractometric detectors (HPSEC-MALLS-RI). Conformations of protein chains of native and illuminated enzymes were evaluated on the basis of their circular dichroism (CD) spectra. Additionally, molecular weight Mw and radii of gyration Rg of polysaccharide chains of microcrystalline cellulose native and digested for 10 min, 480 min and 1440 min with original and WLPL stimulated enzymes WT and TR were taken. Illumination with WLPL of both cellulases studied did not change secondary structures of protein molecules of native enzyme. Molecular weight Mw and radii of gyration Rg of illuminated enzymes differed greatly from those found for native enzymes. Illumination of enzymes led to increase of specific activity and rate constants of reaction of hydrolysis microcrystalline cellulose catalyzed by illuminated enzymes as compared with native enzymes.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.22125110,U23A2094,22205233,22193042,21921001,22305248 and U21A2069)the Natural Science Foundation of Fujian Province(No.2023J02028)+3 种基金the Key Research Program of Frontier Sciences of Chinese Academy of Sciences(No.ZDBS-LY-SLH024)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(No.2021ZR126)the National Key Research and Development Program of China(No.2019YFA0210402)the China Postdoctoral Science Foundation(Nos.2022TQ0337 and 2023M733497).
文摘2D Ruddlesden-Popper(RP)polar perovskite,displaying the intrinsic optical anisotropy and structural polarity,has a fantastic application perspective in self-powered polarized light detection.However,the weak van der Waals interaction between the organic spacing bilayers is insufficient to preserve the stability of RP-type materials.Hence,it is of great significance to explore new stable 2D RP-phase candidates.In this work,we have successfully constructed a highly-stable polar 2D perovskite,(t-ACH)_(2)PbI_(4)(1,where t-ACH^(+)is HOOC_(8)H_(12)NH_(3)^(+)),by adopting a hydrophobic carboxylate trans-isomer of tranexamic acid as the spacing component.Strikingly,strong O-H…O hydrogen bonds between t-ACH^(+)organic bilayers compose the dimer,thus decreasing van der Waals gap and enhancing structural stability.Besides,such orientational hydrogen bonds contribute to the formation of structural polarity and generate an obvious bulk photovoltaic effect in 1,which facilitates its self-powered photodetection.As predicted,the combination of inherent anisotropy and polarity leads to self-powered polarized-light detection with a high ratio of around∼5.3,superior to those of inorganic 2D counterparts.This work paves a potential way to design highly-stable 2D perovskites for high-performance optoelectronic devices.
文摘The phase time of p-polarized light pulses passing through a glass plate is investigated. We do this by converting the problem into a l-dimensional quantum-mechanical counterpart, a potential well with a position-dependent effective mass. We find that the phase time and the lateral shift have the negative characteristics.
文摘The paper studied the relationship between microstructure and shape recovery characteristics by using colored microstructure analysis under polarized light on the thermomechanical cycled CuAlNi single crystals. The two-way shape memory effect in quenched thin bar resulted from the preferential formation/extinction of martensite variant due to the internal quench stress, and the variant was formed at an angle of about 45 deg. with the tension direction ([001] of the βphase). Initial thermomechanical cycling under relatively low stress single variant stress-induced martensite was formed at an angle of 45 deg. with the tension and its morphology was a lath of parallel twins. More than one group of variants were formed after several training cycles and such variants also caused tilting of some thermally formed accommodated martensite. By overheating the trained sample containing stabilized multi-variants of stress-induced martensite, very coarse martensite structure with a strong asymmetry was produced, which caused the reverse two-way shape memory effect.
基金Project supported by the Science and Technology Major Projects of Zhejiang Province,China(Grant No.2013C03043-5)
文摘Digital structured light （SL） profilometry is increasingly used in three-dimensional （3D） measurement technology. However, the nonlinearity of the off-the-shelf projectors and cameras seriously reduces the measurement accuracy. In this paper, first, we review the nonlinear effects of the projector-camera system in the phase-shifting structured light depth measurement method. We show that high order harmonic wave components lead to phase error in the phase-shifting method. Then a practical method based on frequency domain filtering is proposed for nonlinear error reduction. By using this method, the nonlinear calibration of the SL system is not required. Moreover, both the nonlinear effects of the projector and the camera can be effectively reduced. The simulations and experiments have verified our nonlinear correction method.
