We investigate the spatial and temporal correlations of hot-electron generation in high-intensity laser interaction with massive and thin copper targets under conditions relevant to inertial confinement fusion.Using K...We investigate the spatial and temporal correlations of hot-electron generation in high-intensity laser interaction with massive and thin copper targets under conditions relevant to inertial confinement fusion.Using Ka time-resolved imaging,it is found that in the case of massive targets,the hot-electron generation follows the laser pulse intensity with a short delay needed for favorable plasma formation.Conversely,a significant delay in the x-ray emission compared with the laser pulse intensity profile is observed in the case of thin targets.Theoretical analysis and numerical simulations suggest that this is related to radiation preheating of the foil and the increase in hot-electron lifetime in a hot expanding plasma.展开更多
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
基金funding via EUROfusion Enabling research Project No.AWP21-ENR-01-CEA-02“Advancing Shock Ignition for Direct-Drive Inertial Fusion,”the framework of the EUROfusion Consortium,funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No.101052200-EUROfusion)+2 种基金the Czech Ministry of Education,Youth and Sports (CMEYS) for funding the operation of the PALS facility (Grant No.LM2023068)the EuroHPC Joint Undertaking for awarding access to Karolina at IT4Innovations (VSB-TU),Czechia under Project No.EHPC-REG-2023R02-006(DD-23-157)the Ministry of Education,Youth and Sports of the Czech Republic through e-INFRA CZ (Grant No.ID:90140)
文摘We investigate the spatial and temporal correlations of hot-electron generation in high-intensity laser interaction with massive and thin copper targets under conditions relevant to inertial confinement fusion.Using Ka time-resolved imaging,it is found that in the case of massive targets,the hot-electron generation follows the laser pulse intensity with a short delay needed for favorable plasma formation.Conversely,a significant delay in the x-ray emission compared with the laser pulse intensity profile is observed in the case of thin targets.Theoretical analysis and numerical simulations suggest that this is related to radiation preheating of the foil and the increase in hot-electron lifetime in a hot expanding plasma.
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.
