Two-dimensional second-order spatial differentiation metasurfaces with different numerical apertures(NAs)were designed by the spatial-frequency Trust-Region algorithm,which can be directly embedded into existing optic...Two-dimensional second-order spatial differentiation metasurfaces with different numerical apertures(NAs)were designed by the spatial-frequency Trust-Region algorithm,which can be directly embedded into existing optical imaging systems to efficiently extract edge information of the observed targets.The spatial-frequency Trust-Region algorithm was implemented by integrating the Fourier modal method(FMM)with the Trust-Region algorithm to perform inverse optimization of the metasurface nanostructure.The fabricated metasurface with high-resolution functionality achieved a resolution of 1.2μm and numerical aperture of 0.87,while the high-contrast one obtained a root-mean-square(RMS)contrast higher than that of the first with a numerical aperture of 0.26.Embedded in an optical microscope,the high-resolution differentiation metasurface,with more high-spatial-frequency components in the transfer function,was utilized to extract fine structures of unstained,even transparent,cell images,providing a new avenue for image segmentation,such as in magnetic resonance imaging.The high-contrast counterpart,due to its high transmission efficiency,was employed to detect edges in dynamic images of paramecia and Brachionus without motion smear,offering potential for application in microsurgical procedures involving real-time image analysis.展开更多
Polymers are usually restricted on the high exciton binding energies and sluggish electron transfer because of the low dielectric constants.Regulating spin-polarized electrons is regarded as an attractive strategy,but...Polymers are usually restricted on the high exciton binding energies and sluggish electron transfer because of the low dielectric constants.Regulating spin-polarized electrons is regarded as an attractive strategy,but often confined to the d-orbital elements.Here,the nonmetal P and N elements co-mediated the spin polarization of carbon nitrides(PCN)have been elaborately designed.The optimized PCN-3 shows an outstanding hydrogen production(22.2 mmol·g^(-1)·h^(-1))coupled with selective benzylamine oxidation without using any solvent and cocatalysts,which is 200 times of original C_(3)N_(4)and superior to the photocatalysts has been reported to date.Experimental and theoretical results verified that the spin-orbital coupling of N 2p and P 2p remarkably increased the parallel spin states of charge and reduced the formation of singlet excitons to accelerate exciton dissociation in carbon nitride.In addition,charge separation and surface catalysis can be significantly enhanced by the electron spin polarization of carbon nitride with the parallel arrangement,huge built-in electric field and disturbed electronic structure.Our finding deepens the insight into the charge separation and exciton dissociation in spin polarization,and offers new tactics to develop high-efficiency catalysts.展开更多
基金National Natural Science Foundation of China(61927822)。
文摘Two-dimensional second-order spatial differentiation metasurfaces with different numerical apertures(NAs)were designed by the spatial-frequency Trust-Region algorithm,which can be directly embedded into existing optical imaging systems to efficiently extract edge information of the observed targets.The spatial-frequency Trust-Region algorithm was implemented by integrating the Fourier modal method(FMM)with the Trust-Region algorithm to perform inverse optimization of the metasurface nanostructure.The fabricated metasurface with high-resolution functionality achieved a resolution of 1.2μm and numerical aperture of 0.87,while the high-contrast one obtained a root-mean-square(RMS)contrast higher than that of the first with a numerical aperture of 0.26.Embedded in an optical microscope,the high-resolution differentiation metasurface,with more high-spatial-frequency components in the transfer function,was utilized to extract fine structures of unstained,even transparent,cell images,providing a new avenue for image segmentation,such as in magnetic resonance imaging.The high-contrast counterpart,due to its high transmission efficiency,was employed to detect edges in dynamic images of paramecia and Brachionus without motion smear,offering potential for application in microsurgical procedures involving real-time image analysis.
基金supported by the Science and Technology Foundation of Guizhou Province(ZK[2021]yiban 328)the Postgraduate Education Innovation Program in Guizhou Province(YJSCXJH(2021)202)。
基金financially supported by Guizhou Provincial Science and Technology Foundation(No.ZK2021069)Young Science and Technology Talents Development Project of Education Department in Guizhou Province(No.KY2022144)National Natural Science Foundation of China(No.22268015).
文摘Polymers are usually restricted on the high exciton binding energies and sluggish electron transfer because of the low dielectric constants.Regulating spin-polarized electrons is regarded as an attractive strategy,but often confined to the d-orbital elements.Here,the nonmetal P and N elements co-mediated the spin polarization of carbon nitrides(PCN)have been elaborately designed.The optimized PCN-3 shows an outstanding hydrogen production(22.2 mmol·g^(-1)·h^(-1))coupled with selective benzylamine oxidation without using any solvent and cocatalysts,which is 200 times of original C_(3)N_(4)and superior to the photocatalysts has been reported to date.Experimental and theoretical results verified that the spin-orbital coupling of N 2p and P 2p remarkably increased the parallel spin states of charge and reduced the formation of singlet excitons to accelerate exciton dissociation in carbon nitride.In addition,charge separation and surface catalysis can be significantly enhanced by the electron spin polarization of carbon nitride with the parallel arrangement,huge built-in electric field and disturbed electronic structure.Our finding deepens the insight into the charge separation and exciton dissociation in spin polarization,and offers new tactics to develop high-efficiency catalysts.
