Terahertz(THz)metamaterials,with their exceptional ability to precisely manipulate the phase,amplitude,polarization and orbital angular momentum(OAM)of electromagnetic waves,have demonstrated significant application p...Terahertz(THz)metamaterials,with their exceptional ability to precisely manipulate the phase,amplitude,polarization and orbital angular momentum(OAM)of electromagnetic waves,have demonstrated significant application potential across a wide range of fields.However,traditional design methodologies often rely on extensive parameter sweeps,making it challenging to address the increasingly complex and diverse application requirements.Recently,the integration of artificial intelligence(AI)techniques,particularly deep learning and optimization algorithms,has introduced new approaches for the design of THz metamaterials.This paper reviews the fundamental principles of THz metamaterials and their intelligent design methodologies,with a particular focus on the advancements in AI-driven inverse design of THz metamaterials.The AI-driven inverse design process allows for the creation of THz metamaterials with desired properties by working backward from the unit structures and array configurations of THz metamaterials,thereby accelerating the design process and reducing both computational resources and time.It examines the critical role of AI in improving both the functionality and design efficiency of THz metamaterials.Finally,we outline future research directions and technological challenges,with the goal of providing valuable insights and guidance for ongoing and future investigations.展开更多
The state of polarization(SOP)on high-order Poincaréspheres(HOPSs),characterized by their distinctive phase profiles and polarization distributions,plays a crucial role in both classical and quantum optical appli...The state of polarization(SOP)on high-order Poincaréspheres(HOPSs),characterized by their distinctive phase profiles and polarization distributions,plays a crucial role in both classical and quantum optical applications.However,most existing metasurface-based implementations face inherent limitations:passive designs are restricted to represent a few predefined HOPS SOPs,while programmable versions typically constrain to 1-bit or 2-bit phase control resolution.In this paper,dynamic generation of HOPS beams with arbitrary SOP based on a transmissive space-time-coding metasurface is demonstrated.By combining 1-bit phase discretizations via PIN diodes with a time-coding strategy,the metasurface enables quasi-continuous complexamplitude modulation for harmonic waves in both x-and y-polarizations.Based on near-field diffraction theory,arbitrary SOPs on any HOPSm,n can be precisely generated using a linearly polarized basis,which is independently controlled by FPGA reconfiguration.We experimentally demonstrate that polarization holography on HOPS0,0 achieves high polarization purity>91.28%,and vector vortex beams on HOPS1,3 and HOPS−1,3 exhibit high orbital angular momentum mode purities>91.25%.This methodology holds great potential for structured wavefront shaping,vortex generation,and high-capacity planar photonics.展开更多
Dynamic generation of multimode vortex waves carrying orbital angular momentum(OAM)utilizing programmable metasurfaces has attracted considerable attention.Yet,it is still a challenge to achieve multiplexed vortex wav...Dynamic generation of multimode vortex waves carrying orbital angular momentum(OAM)utilizing programmable metasurfaces has attracted considerable attention.Yet,it is still a challenge to achieve multiplexed vortex waves with an arbitrary customized mode combination,stemming fundamentally from the discrete control over phase exhibited by current programmable metasurfaces,which are typically constrained to a limited 1-bit or 2-bit discrete resolution.In this paper,we propose,to our knowledge,a new strategy for dynamic generation of multiplexed vortex beams based on a space-time-coding metasurface,capable of quasi-continuous complex-amplitude modulation for harmonic waves.As a proof of concept,a metasurface prototype for generating multiplexed vortex beams with the customized mode composition and power allocation is established based on the transmissive space-time-coding meta-atoms regulated by the field programmable gate array controller.The mode purity of the vortex beams with a single OAM mode of+1,+2,and+3 generated by the metasurface is as high as over 0.93.The generated multiplexed vortex beams carrying(+1,+2,+3)OAM modes with a power ratio of 1:1:1,(+1,+2,+3)modes with a power ratio of 1:2:3,and(-2,-1,+1,+2)modes with a power ratio of 1:2:2:1 are further verified effectively.The proposed space-time-coding metasurface has great potential for OAM multiplexing communication systems.展开更多
基金supported by the National Key R and D Program of China(No.2022YFF0604801)the National Natural Science Foundation of China(Nos.62271056,62171186,62201037)+3 种基金the Technology Innovation Center of Infrared Remote Sensing Metrology Technology of State Administration for Market Regulation(No.AKYKF2423)the Beijing Natural Science Foundation of China-Haidian Original Innovation Joint Fund(No.L222042)the Open Research Fund of State Key Laboratory of Millimeter Waves(No.K202326)the 111 Project of China(No.B14010).
文摘Terahertz(THz)metamaterials,with their exceptional ability to precisely manipulate the phase,amplitude,polarization and orbital angular momentum(OAM)of electromagnetic waves,have demonstrated significant application potential across a wide range of fields.However,traditional design methodologies often rely on extensive parameter sweeps,making it challenging to address the increasingly complex and diverse application requirements.Recently,the integration of artificial intelligence(AI)techniques,particularly deep learning and optimization algorithms,has introduced new approaches for the design of THz metamaterials.This paper reviews the fundamental principles of THz metamaterials and their intelligent design methodologies,with a particular focus on the advancements in AI-driven inverse design of THz metamaterials.The AI-driven inverse design process allows for the creation of THz metamaterials with desired properties by working backward from the unit structures and array configurations of THz metamaterials,thereby accelerating the design process and reducing both computational resources and time.It examines the critical role of AI in improving both the functionality and design efficiency of THz metamaterials.Finally,we outline future research directions and technological challenges,with the goal of providing valuable insights and guidance for ongoing and future investigations.
基金National Natural Science Foundation of China(62271056,62171186,62201037)Technology Innovation Center of Infrared Remote Sensing Metrology Technology of State Administration for Market Regulation(AKYKF2423)+5 种基金National Key Research and Development Program of China(2022YFF0604801)Beijing Natural Science Foundation Haidian Original Innovation Joint Fund(L222042)Open Research Fund of State Key Laboratory of Millimeter Waves(K202326)Open Research Fund of State Key Laboratory of Space-Ground Integrated Information Technology(6142221200201)Basic Research Foundation of Beijing Institute of Technology,China(BITBLR2020014)111 Project of China(B14010).
文摘The state of polarization(SOP)on high-order Poincaréspheres(HOPSs),characterized by their distinctive phase profiles and polarization distributions,plays a crucial role in both classical and quantum optical applications.However,most existing metasurface-based implementations face inherent limitations:passive designs are restricted to represent a few predefined HOPS SOPs,while programmable versions typically constrain to 1-bit or 2-bit phase control resolution.In this paper,dynamic generation of HOPS beams with arbitrary SOP based on a transmissive space-time-coding metasurface is demonstrated.By combining 1-bit phase discretizations via PIN diodes with a time-coding strategy,the metasurface enables quasi-continuous complexamplitude modulation for harmonic waves in both x-and y-polarizations.Based on near-field diffraction theory,arbitrary SOPs on any HOPSm,n can be precisely generated using a linearly polarized basis,which is independently controlled by FPGA reconfiguration.We experimentally demonstrate that polarization holography on HOPS0,0 achieves high polarization purity>91.28%,and vector vortex beams on HOPS1,3 and HOPS−1,3 exhibit high orbital angular momentum mode purities>91.25%.This methodology holds great potential for structured wavefront shaping,vortex generation,and high-capacity planar photonics.
基金National Key Research and Development Program of China(2022YFF0604801)National Natural Science Foundation of China(62271056,62171186,62201037)+4 种基金Beijing Natural Science Foundation of China-Haidian Original Innovation Joint Fund(L222042)Open Research Fund of State Key Laboratory of Millimeter Waves(K202326)Open Research Fund of State Key Laboratory of Space-Ground Integrated Information Technology(6142221200201)Basic Research Foundation of Beijing Institute of Technology,China(BITBLR2020014)111 Project of China(B14010).
文摘Dynamic generation of multimode vortex waves carrying orbital angular momentum(OAM)utilizing programmable metasurfaces has attracted considerable attention.Yet,it is still a challenge to achieve multiplexed vortex waves with an arbitrary customized mode combination,stemming fundamentally from the discrete control over phase exhibited by current programmable metasurfaces,which are typically constrained to a limited 1-bit or 2-bit discrete resolution.In this paper,we propose,to our knowledge,a new strategy for dynamic generation of multiplexed vortex beams based on a space-time-coding metasurface,capable of quasi-continuous complex-amplitude modulation for harmonic waves.As a proof of concept,a metasurface prototype for generating multiplexed vortex beams with the customized mode composition and power allocation is established based on the transmissive space-time-coding meta-atoms regulated by the field programmable gate array controller.The mode purity of the vortex beams with a single OAM mode of+1,+2,and+3 generated by the metasurface is as high as over 0.93.The generated multiplexed vortex beams carrying(+1,+2,+3)OAM modes with a power ratio of 1:1:1,(+1,+2,+3)modes with a power ratio of 1:2:3,and(-2,-1,+1,+2)modes with a power ratio of 1:2:2:1 are further verified effectively.The proposed space-time-coding metasurface has great potential for OAM multiplexing communication systems.
