Programmable metasurfaces are revolutionizing the field of communication and perception by dynamically modulating properties such as amplitude and phase of electromagnetic(EM)waves.Nevertheless,it is challenging for e...Programmable metasurfaces are revolutionizing the field of communication and perception by dynamically modulating properties such as amplitude and phase of electromagnetic(EM)waves.Nevertheless,it is challenging for existing programmable metasurfaces to attain fully independent dynamic modulation of amplitude and phase due to the significant correlation between these two parameters.In this paper,we propose a radiation-type metasurface that can realize radiation space-time coding of the joint amplitude-phase.Hence,independent and arbitrary modulation of amplitudes and phases can be achieved for both x-polarized and y-polarized EM waves.For demonstration,the dynamic beam scanning with ultra-low sidelobe levels(SLLs)is validated.Moreover,we propose a strategy of stochastic coding and non-uniform modulation to suppress the harmonic energy,thereby obtaining the ultra-low sideband levels(SBLs).Prototypes were fabricated and measured,and all simulations and measurements demonstrated the superiority of the proposed strategy.In addition,the proposed strategy is optimization-free and highly integrated,which has unrivaled potential in the field of compact communication systems and radar systems.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
基金National Key Research and Development Program of China(SQ2022YFB3806200)National Natural Science Foundation of China(52272101)+1 种基金Natural Science Foundation of Shaanxi Province(2024JC-YBMS-462,2024JC-YBMS-518,2024JC-YBQN-0721)Science and Technology Innovation Team of Shaanxi Province(2023-CX-TD-48)。
文摘Programmable metasurfaces are revolutionizing the field of communication and perception by dynamically modulating properties such as amplitude and phase of electromagnetic(EM)waves.Nevertheless,it is challenging for existing programmable metasurfaces to attain fully independent dynamic modulation of amplitude and phase due to the significant correlation between these two parameters.In this paper,we propose a radiation-type metasurface that can realize radiation space-time coding of the joint amplitude-phase.Hence,independent and arbitrary modulation of amplitudes and phases can be achieved for both x-polarized and y-polarized EM waves.For demonstration,the dynamic beam scanning with ultra-low sidelobe levels(SLLs)is validated.Moreover,we propose a strategy of stochastic coding and non-uniform modulation to suppress the harmonic energy,thereby obtaining the ultra-low sideband levels(SBLs).Prototypes were fabricated and measured,and all simulations and measurements demonstrated the superiority of the proposed strategy.In addition,the proposed strategy is optimization-free and highly integrated,which has unrivaled potential in the field of compact communication systems and radar systems.
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.
