Terahertz science and technology promise many cutting-edge applications.Terahertz surface plasmonic waves that propagate at metal–dielectric interfaces deliver a potentially effective way to realize integrated terahe...Terahertz science and technology promise many cutting-edge applications.Terahertz surface plasmonic waves that propagate at metal–dielectric interfaces deliver a potentially effective way to realize integrated terahertz devices and systems.Previous concerns regarding terahertz surface plasmonic waves have been based on their highly delocalized feature.However,recent advances in plasmonics indicate that the confinement of terahertz surface plasmonic waves,as well as their propagating behaviors,can be engineered by designing the surface environments,shapes,structures,materials,etc.,enabling a unique and fascinating regime of plasmonic waves.Together with the essential spectral property of terahertz radiation,as well as the increasingly developed materials,microfabrication,and time-domain spectroscopy technologies,devices and systems based on terahertz surface plasmonic waves may pave the way toward highly integrated platforms for multifunctional operation,implementation,and processing of terahertz waves in both fundamental science and practical applications.We present a review on terahertz surface plasmonic waves on various types of supports in a sequence of properties,excitation and detection,and applications.The current research trend and outlook of possible research directions for terahertz surface plasmonic waves are also outlined.展开更多
Nodal lines are degeneracies formed by crossing bands in three-dimensional momentum space.Interestingly,these degenerate lines can chain together via touching points and manifest as nodal chains.These nodal chains are...Nodal lines are degeneracies formed by crossing bands in three-dimensional momentum space.Interestingly,these degenerate lines can chain together via touching points and manifest as nodal chains.These nodal chains are usually embedded in two orthogonal planes and protected by the corresponding mirror symmetries.Here,we propose and demonstrate an in-plane nodal chain in photonics,where all chained nodal lines coexist in a single mirror plane instead of two orthogonal ones.Nodal lines are degeneracies formed by crossing bands in three-dimensional momentum space.Interestingly,these degenerate lines can chain together via touching points and manifest as nodal chains.These nodal chains are usually embedded in two orthogonal planes and protected by the corresponding mirror symmetries.Here,we propose and demonstrate an in-plane nodal chain in photonics,where all chained nodal lines coexist in a single mirror plane instead of two orthogonal ones.The chain point is stabilized by the intrinsic symmetry that is specific to electromagnetic waves at theГpoint of zero frequency.By adding another mirror plane,we find a nodal ring that is constructed by two higher bands and links with the in-plane nodal chain.The nodal link in momentum space exhibits non-Abelian characteristics on a C_(2)T-invariant plane,where admissible transitions of the nodal link structure are determined by generalized quaternion charges.Through near-field scanning measurements of bi-anisotropic metamaterials,we experimentally mapped out the in-plane nodal chain and nodal link in such systems.The chain point is stabilized by the intrinsic symmetry that is specific to electromagnetic waves at the r point of zero frequency.By adding another mirror plane,we find a nodal ring that is constructed by two higher bands and links with the in-plane nodal chain.The nodal link in momentum space exhibits non-Abelian characteristics on a C2T-invariant plane,where admissible transitions of the nodal link structure are determined by generalized quaternion charges.Through near-field scanning measurements of bi-anisotropic metamaterials,we experimentally mapped out the in-plane nodal chain and nodal link in such systems.展开更多
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.61935015,61735012,61605143,61622505,61575141,61722509,61675145,and 61775159)the Tianjin Municipal Fund for Distinguished Young Scholars(Grant No.18JCJQJC45600).
文摘Terahertz science and technology promise many cutting-edge applications.Terahertz surface plasmonic waves that propagate at metal–dielectric interfaces deliver a potentially effective way to realize integrated terahertz devices and systems.Previous concerns regarding terahertz surface plasmonic waves have been based on their highly delocalized feature.However,recent advances in plasmonics indicate that the confinement of terahertz surface plasmonic waves,as well as their propagating behaviors,can be engineered by designing the surface environments,shapes,structures,materials,etc.,enabling a unique and fascinating regime of plasmonic waves.Together with the essential spectral property of terahertz radiation,as well as the increasingly developed materials,microfabrication,and time-domain spectroscopy technologies,devices and systems based on terahertz surface plasmonic waves may pave the way toward highly integrated platforms for multifunctional operation,implementation,and processing of terahertz waves in both fundamental science and practical applications.We present a review on terahertz surface plasmonic waves on various types of supports in a sequence of properties,excitation and detection,and applications.The current research trend and outlook of possible research directions for terahertz surface plasmonic waves are also outlined.
基金This work is supported by the Research Grants Council of Hong Kong,China(AoE/P-02/12,16304717,16310420)the Hong Kong Scholars Program(XJ2019007)+2 种基金W.-J.C.is supported by the National Natural Science Foundation of China(Grant no.11874435)J.H.is supported by the National Natural Science Foundation of China(Grant no.62025504,61935015)S.Z.acknowledges support from the ERC Consolidator Grant(TOPOLOGICAL),the Royal Society,and the Wolfson Foundation.
文摘Nodal lines are degeneracies formed by crossing bands in three-dimensional momentum space.Interestingly,these degenerate lines can chain together via touching points and manifest as nodal chains.These nodal chains are usually embedded in two orthogonal planes and protected by the corresponding mirror symmetries.Here,we propose and demonstrate an in-plane nodal chain in photonics,where all chained nodal lines coexist in a single mirror plane instead of two orthogonal ones.Nodal lines are degeneracies formed by crossing bands in three-dimensional momentum space.Interestingly,these degenerate lines can chain together via touching points and manifest as nodal chains.These nodal chains are usually embedded in two orthogonal planes and protected by the corresponding mirror symmetries.Here,we propose and demonstrate an in-plane nodal chain in photonics,where all chained nodal lines coexist in a single mirror plane instead of two orthogonal ones.The chain point is stabilized by the intrinsic symmetry that is specific to electromagnetic waves at theГpoint of zero frequency.By adding another mirror plane,we find a nodal ring that is constructed by two higher bands and links with the in-plane nodal chain.The nodal link in momentum space exhibits non-Abelian characteristics on a C_(2)T-invariant plane,where admissible transitions of the nodal link structure are determined by generalized quaternion charges.Through near-field scanning measurements of bi-anisotropic metamaterials,we experimentally mapped out the in-plane nodal chain and nodal link in such systems.The chain point is stabilized by the intrinsic symmetry that is specific to electromagnetic waves at the r point of zero frequency.By adding another mirror plane,we find a nodal ring that is constructed by two higher bands and links with the in-plane nodal chain.The nodal link in momentum space exhibits non-Abelian characteristics on a C2T-invariant plane,where admissible transitions of the nodal link structure are determined by generalized quaternion charges.Through near-field scanning measurements of bi-anisotropic metamaterials,we experimentally mapped out the in-plane nodal chain and nodal link in such systems.