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
Spherulitic morphology of pure poly lactic acid (PLLA) PLLA have investigated after thermal annealing. The morphology of spherulite of pure poly lactic acid (PLLA) PLLA have investigated after thermal annealing. The e...Spherulitic morphology of pure poly lactic acid (PLLA) PLLA have investigated after thermal annealing. The morphology of spherulite of pure poly lactic acid (PLLA) PLLA have investigated after thermal annealing. The effect of both annealing temperature and crystallization temperature on the formation of cracks was described by polarized optical microscope (POM). Non banded spherulite (fibrils) with cracks was detected in PLLA film after annealing at 160°C (180 min.) and isothermal crystallization temperatures at 140°C and 150°C. With increasing temperature after annealing treatment the size of spherulite is increased and more cracks are formed. The maximum growth rate of spherulites was found at 130°C. The physical ageing was carried out by annealing the PLLA sample at room temperature for several annealing time (ta) from 0 h to 720 h. The enthalpy relaxation has been studied by differential scanning calorimetry (DSC) through analysis of the endothermic peak of glass transition temperature, which increased and shifted towards higher temperature as the annealing time increased.展开更多
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.
文摘Spherulitic morphology of pure poly lactic acid (PLLA) PLLA have investigated after thermal annealing. The morphology of spherulite of pure poly lactic acid (PLLA) PLLA have investigated after thermal annealing. The effect of both annealing temperature and crystallization temperature on the formation of cracks was described by polarized optical microscope (POM). Non banded spherulite (fibrils) with cracks was detected in PLLA film after annealing at 160°C (180 min.) and isothermal crystallization temperatures at 140°C and 150°C. With increasing temperature after annealing treatment the size of spherulite is increased and more cracks are formed. The maximum growth rate of spherulites was found at 130°C. The physical ageing was carried out by annealing the PLLA sample at room temperature for several annealing time (ta) from 0 h to 720 h. The enthalpy relaxation has been studied by differential scanning calorimetry (DSC) through analysis of the endothermic peak of glass transition temperature, which increased and shifted towards higher temperature as the annealing time increased.
