The metalens has attracted remarkable attention due to its ultra-thin and ultra-light characteristics,which indicate great potential for compact imaging.However,the limited efficiency at a large angle incidence severe...The metalens has attracted remarkable attention due to its ultra-thin and ultra-light characteristics,which indicate great potential for compact imaging.However,the limited efficiency at a large angle incidence severely hinders the application of wide-angle focusing and imaging,which is pursued in the fast-developing imaging systems.Therefore,new strategies to improve the lens performance at large incident angles are in demand.In this work,we propose tilted structures for largeangle focusing with improved efficiency.Metalenses based on dynamic phase and geometric phase are designed and systematically characterized by numerical simulations.We show that tilted structures of unit cells significantly improve the lens performance at oblique incidences.In detail,the focusing efficiency of the metalens with tilted structures is increased over 25%at 30°incidence,as well as the modulation transfer function.In addition,we develop a hybrid metalens array achieving highly efficient wide-angle imaging up to 120°.We believe this design provides a feasible route toward wide-field and high-performance imaging applications.展开更多
In this Letter,we propose a metagrating consisting of simple rectangular bars for nearly unity anomalous diffraction with a large deflection angle.The analysis performed by the scattering-matrix method shows that such...In this Letter,we propose a metagrating consisting of simple rectangular bars for nearly unity anomalous diffraction with a large deflection angle.The analysis performed by the scattering-matrix method shows that such exceptional beam steering derives from the couplings of the two lowest propagation waveguide-array-modes and their constructive interferences.The tolerance of the incident angle for a high diffraction efficiency(e.g.,>90%)is within a range of 33°.We also discuss that such an advantage still exists after considering a reasonable loss and dispersion.We envision that the proposed strategy may have wide use in the field of high-performance wavefront-shaping applications.展开更多
Since the discovery of high-temperature superconductor YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7</sub>（YBCO） people aremuch concerned about its microwave surface resistance. It was fou...Since the discovery of high-temperature superconductor YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7</sub>（YBCO） people aremuch concerned about its microwave surface resistance. It was found that although themicrowave surface resistance of c-axis oriented YBCO thin films is an order of magnitudelower than Cu, it is much higher than the value predicted by the BCS theory, and also展开更多
AIM: To evaluate the moderate-term success and calculate the mean dose-effect ratio in large-angle esotropic patients who underwent three muscle surgery.METHODS: In a retrospective study, we reviewed the medical recor...AIM: To evaluate the moderate-term success and calculate the mean dose-effect ratio in large-angle esotropic patients who underwent three muscle surgery.METHODS: In a retrospective study, we reviewed the medical records of 37 patients with large-angle esotropia who underwent bilateral medial rectus recession and one lateral rectus resection. Sex, age at surgery time, amount of recessed or resected muscles in millimeter(mm), preand postoperative alignment in prism diopter(D), dose/response ratio, and presence of amblyopia and other associated vertical deviations were recorded.RESULTS: The mean age of subjects at surgery was 12.2±12.3 y(range: 1-57). The mean preoperative deviation of 70.4±8.1 D(range: 60-85 D) decreased to a mean of 5.4±8.1 D(range: 0-30 D) postoperatively(P<0.005). Successful alignment was achieved in 30 of 37 patients(81%) at a mean follow-up of 15.7±20.1 mo(range: 3-90). The mean amount of recession and resection was 17.59±1.29 mm, and a mean dose-response ratio of 3.79±81(range: 2.83-4.66) was determined.CONCLUSION: Three-muscle surgery for large-angle esotropia results in good moderate-term outcomes without high rates of overcorrection or undercorrection.展开更多
基金This work was supported by the National Key Research and Development Program of China(No.2022YFA1404301)National Natural Science Foundation of China(Nos.62325504,62305149,92250304,and 62288101).
文摘The metalens has attracted remarkable attention due to its ultra-thin and ultra-light characteristics,which indicate great potential for compact imaging.However,the limited efficiency at a large angle incidence severely hinders the application of wide-angle focusing and imaging,which is pursued in the fast-developing imaging systems.Therefore,new strategies to improve the lens performance at large incident angles are in demand.In this work,we propose tilted structures for largeangle focusing with improved efficiency.Metalenses based on dynamic phase and geometric phase are designed and systematically characterized by numerical simulations.We show that tilted structures of unit cells significantly improve the lens performance at oblique incidences.In detail,the focusing efficiency of the metalens with tilted structures is increased over 25%at 30°incidence,as well as the modulation transfer function.In addition,we develop a hybrid metalens array achieving highly efficient wide-angle imaging up to 120°.We believe this design provides a feasible route toward wide-field and high-performance imaging applications.
基金supported by the State Key Research and Development Program of China(No.2019YFB2203502)the National Natural Science Foundation of China(Nos.11761161002 and 61775243)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(No.2018B030308005)the Science and Technology Program of Guangzhou(No.201804020029)
文摘In this Letter,we propose a metagrating consisting of simple rectangular bars for nearly unity anomalous diffraction with a large deflection angle.The analysis performed by the scattering-matrix method shows that such exceptional beam steering derives from the couplings of the two lowest propagation waveguide-array-modes and their constructive interferences.The tolerance of the incident angle for a high diffraction efficiency(e.g.,>90%)is within a range of 33°.We also discuss that such an advantage still exists after considering a reasonable loss and dispersion.We envision that the proposed strategy may have wide use in the field of high-performance wavefront-shaping applications.
基金Project supported by the National Center for Research and Development on Superconductivity.
文摘Since the discovery of high-temperature superconductor YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7</sub>（YBCO） people aremuch concerned about its microwave surface resistance. It was found that although themicrowave surface resistance of c-axis oriented YBCO thin films is an order of magnitudelower than Cu, it is much higher than the value predicted by the BCS theory, and also
文摘AIM: To evaluate the moderate-term success and calculate the mean dose-effect ratio in large-angle esotropic patients who underwent three muscle surgery.METHODS: In a retrospective study, we reviewed the medical records of 37 patients with large-angle esotropia who underwent bilateral medial rectus recession and one lateral rectus resection. Sex, age at surgery time, amount of recessed or resected muscles in millimeter(mm), preand postoperative alignment in prism diopter(D), dose/response ratio, and presence of amblyopia and other associated vertical deviations were recorded.RESULTS: The mean age of subjects at surgery was 12.2±12.3 y(range: 1-57). The mean preoperative deviation of 70.4±8.1 D(range: 60-85 D) decreased to a mean of 5.4±8.1 D(range: 0-30 D) postoperatively(P<0.005). Successful alignment was achieved in 30 of 37 patients(81%) at a mean follow-up of 15.7±20.1 mo(range: 3-90). The mean amount of recession and resection was 17.59±1.29 mm, and a mean dose-response ratio of 3.79±81(range: 2.83-4.66) was determined.CONCLUSION: Three-muscle surgery for large-angle esotropia results in good moderate-term outcomes without high rates of overcorrection or undercorrection.
