Dynamic beam steering with unlimited angular range and fast speed remains a challenge in the terahertz gap,which is urgently needed for next-generation target tracking,wireless communications,and imaging applications....Dynamic beam steering with unlimited angular range and fast speed remains a challenge in the terahertz gap,which is urgently needed for next-generation target tracking,wireless communications,and imaging applications.Different from metasurface phased arrays with element-level phase control,here we steer the beam by globally engineering the diffraction of two cascaded metagratings during in-plane rotation.Benefiting from large-angle diffraction and flexible on/off control of the diffraction channels,a pair of metagratings with optimized supercells and proper orientation successfully directs the incoming beam towards any arbitrary direction over the transmission half space,with the steering speed improved more than twice that of the small-angle diffractive designs.Single-beam and dual-beam steering within the solid angle of 1.56πand elevation angle of±77°has been demonstrated with average throughput efficiency of 41.4%at 0.14 THz,which can be generalized to multiple-beam cases.The dual diffraction engineering scheme offers a clear physical picture for beamforming and greatly simplifies the device structure,with additional merits of large aperture and low power consumption.展开更多
Surface plasmons have been given high expectations in terahertz(THz)on-chip photonics with highly bound integrated transmission and on-chip wavefront engineering.However,most surface plasmonic coupling strategies with...Surface plasmons have been given high expectations in terahertz(THz)on-chip photonics with highly bound integrated transmission and on-chip wavefront engineering.However,most surface plasmonic coupling strategies with tailorable polarization-dependent features are challenged in broadband propagation and dynamic manipulation.In this work,a liquid crystal(LC)-integrated surface plasmonic metadevice based on arc-arrayed pair-slit resonators(APSRs)is demonstrated.The mirror-symmetry structures of this metadevice achieve the spin-selective unidirectional achromatic focusing,of which the broadband characteristic is supported by containing multiple APSRs with slits of different sizes corresponding to different excitation frequencies.Moreover,arc radii are precisely designed to meet the phase matching condition of constructive interference,so that the operating frequency of this on-chip metadevice is broadened to 0.33–0.60 THz.Furthermore,the LC integration provides the active energy distribution between the left and right focal spots,and the actual modulation depth reaches up to 73%.These THz active,wideband,on-chip manipulation mechanisms and their devices are of great significance for THz-integrated photonic communication,information processing,and highly sensitive sensing.展开更多
基金National Key Research and Development Program of China(2017YFA0701000)National Natural Science Foundation of China(61831012,62005140,62175118)。
文摘Dynamic beam steering with unlimited angular range and fast speed remains a challenge in the terahertz gap,which is urgently needed for next-generation target tracking,wireless communications,and imaging applications.Different from metasurface phased arrays with element-level phase control,here we steer the beam by globally engineering the diffraction of two cascaded metagratings during in-plane rotation.Benefiting from large-angle diffraction and flexible on/off control of the diffraction channels,a pair of metagratings with optimized supercells and proper orientation successfully directs the incoming beam towards any arbitrary direction over the transmission half space,with the steering speed improved more than twice that of the small-angle diffractive designs.Single-beam and dual-beam steering within the solid angle of 1.56πand elevation angle of±77°has been demonstrated with average throughput efficiency of 41.4%at 0.14 THz,which can be generalized to multiple-beam cases.The dual diffraction engineering scheme offers a clear physical picture for beamforming and greatly simplifies the device structure,with additional merits of large aperture and low power consumption.
基金National Natural Science Foundation of China(62205160,62235004,62335012,62371258)Fundamental Research Funds for the Central Universities(Nankai University)(63241330)。
文摘Surface plasmons have been given high expectations in terahertz(THz)on-chip photonics with highly bound integrated transmission and on-chip wavefront engineering.However,most surface plasmonic coupling strategies with tailorable polarization-dependent features are challenged in broadband propagation and dynamic manipulation.In this work,a liquid crystal(LC)-integrated surface plasmonic metadevice based on arc-arrayed pair-slit resonators(APSRs)is demonstrated.The mirror-symmetry structures of this metadevice achieve the spin-selective unidirectional achromatic focusing,of which the broadband characteristic is supported by containing multiple APSRs with slits of different sizes corresponding to different excitation frequencies.Moreover,arc radii are precisely designed to meet the phase matching condition of constructive interference,so that the operating frequency of this on-chip metadevice is broadened to 0.33–0.60 THz.Furthermore,the LC integration provides the active energy distribution between the left and right focal spots,and the actual modulation depth reaches up to 73%.These THz active,wideband,on-chip manipulation mechanisms and their devices are of great significance for THz-integrated photonic communication,information processing,and highly sensitive sensing.
