Vortex beams carrying orbital angular momentum have important applications in high dimensional optical information processing,manipulations of tiny particles,super-resolution imaging and so on.Among various optical co...Vortex beams carrying orbital angular momentum have important applications in high dimensional optical information processing,manipulations of tiny particles,super-resolution imaging and so on.Among various optical components,metasurface represents an ideal platform for realizing vortex beams with multiple optical functionalities due to its strong ability in manipulating the phase,polarization and amplitude of light.A metasurface combing the functions of a lens and a vortex beam generator can greatly shrink the size of many optical systems.Here,we alternatively propose a new metasurface design based on the concept of a Fresnel zone plate to generate,focus the vortex beams,and perform on-axis interference between different vortex beams.These functions are experimentally demonstrated through encoding the spiral phase profiles into the odd and even zones of a dielectric metasurface.The proposed vortex beam generation strategy employs the advantages of both the Fresnel zone plate and the metasurface,and may open new routes for high-dimensional optical information processing.展开更多
Electric-field-induced second harmonic generation(EFISH),a third-order nonlinear process,arises from the interaction between the electric field of an external bias and that of two incident photons.EFISH can be used to...Electric-field-induced second harmonic generation(EFISH),a third-order nonlinear process,arises from the interaction between the electric field of an external bias and that of two incident photons.EFISH can be used to dynamically control the nonlinear optical response of materials and is therefore promising for active nonlinear devices.However,it has been challenging to achieve a strong modulation with EFISH in conventional nonlinear materials.Here,we report a large tunability of an EFISH signal from a subwavelength-thick polymer film sandwiched between a transparent electrode and a metallic mirror.By exploiting the band-edge-enhanced third-order nonlinear susceptibility of the organic conjugated polymer,we successfully demonstrate a gigantic EFISH effect with a modulation ratio up to 422%V^(−1) at a pumping wavelength of 840 nm.The band-edge-enhanced EFISH opens new avenues for modulating the intensity of SHG signals and for controlling nonlinear electro-optic interactions in nanophotonic devices.展开更多
基金supported by the National Natural Science Foundation of China(91950114,11774145)China Postdoctoral Science Foundation(No.2020 M680271)+3 种基金Guangdong Provincial Innovation and Entrepreneurship Project(2017ZT07C071)Natural Science Foundation of Shenzhen Innovation Commission(JCYJ20200109140808088)Shenzhen DRC project[2018]1433Beijing Postdoctoral Research Foundation(Q6101013202101).
文摘Vortex beams carrying orbital angular momentum have important applications in high dimensional optical information processing,manipulations of tiny particles,super-resolution imaging and so on.Among various optical components,metasurface represents an ideal platform for realizing vortex beams with multiple optical functionalities due to its strong ability in manipulating the phase,polarization and amplitude of light.A metasurface combing the functions of a lens and a vortex beam generator can greatly shrink the size of many optical systems.Here,we alternatively propose a new metasurface design based on the concept of a Fresnel zone plate to generate,focus the vortex beams,and perform on-axis interference between different vortex beams.These functions are experimentally demonstrated through encoding the spiral phase profiles into the odd and even zones of a dielectric metasurface.The proposed vortex beam generation strategy employs the advantages of both the Fresnel zone plate and the metasurface,and may open new routes for high-dimensional optical information processing.
基金financially supported by the National Natural Science Foundation of China(11774145)the Guangdong Provincial Innovation and Entrepreneurship Project(2017ZT07C071)+3 种基金the Applied Science and Technology Project of Guangdong Science and Technology Department(2017B090918001)the Natural Science Foundation of Shenzhen Innovation Committee(JCYJ20170412153113701)the Marie Curie Individual Fellowship(H2020-MSCA-IF-703803-NonlinearMeta)the European Research Council Consolidator Grant(TOPOLOGICAL).
文摘Electric-field-induced second harmonic generation(EFISH),a third-order nonlinear process,arises from the interaction between the electric field of an external bias and that of two incident photons.EFISH can be used to dynamically control the nonlinear optical response of materials and is therefore promising for active nonlinear devices.However,it has been challenging to achieve a strong modulation with EFISH in conventional nonlinear materials.Here,we report a large tunability of an EFISH signal from a subwavelength-thick polymer film sandwiched between a transparent electrode and a metallic mirror.By exploiting the band-edge-enhanced third-order nonlinear susceptibility of the organic conjugated polymer,we successfully demonstrate a gigantic EFISH effect with a modulation ratio up to 422%V^(−1) at a pumping wavelength of 840 nm.The band-edge-enhanced EFISH opens new avenues for modulating the intensity of SHG signals and for controlling nonlinear electro-optic interactions in nanophotonic devices.
