3-dB couplers,which are commonly used in photonic integrated circuits for on-chip information processing,precision measurement,and quantum computing,face challenges in achieving robust performance due to their limited...3-dB couplers,which are commonly used in photonic integrated circuits for on-chip information processing,precision measurement,and quantum computing,face challenges in achieving robust performance due to their limited 3-dB bandwidths and sensitivity to fabrication errors.To address this,we introduce topological physics to nanophotonics,developing a framework for topological 3-dB couplers.These couplers exhibit broad working wavelength range and robustness against fabrication dimensional errors.By leveraging valley-Hall topology and mirror symmetry,the photonic-crystal-slab couplers achieve ideal 3-dB splitting characterized by a wavelength-insensitive scattering matrix.Tolerance analysis confirms the superiority on broad bandwidth of 48 nm and robust splitting against dimensional errors of 20 nm.We further propose a topological interferometer for on-chip distance measurement,which also exhibits robustness against dimensional errors.This extension of topological principles to the fields of interferometers,may open up new possibilities for constructing robust wavelength division multiplexing,temperature-drift-insensitive sensing,and optical coherence tomography applications.展开更多
Three-dimensional(3D)artificial metacrystals host rich topological phases,such as Weyl points,nodal rings,and 3D photonic topological insulators.These topological states enable a wide range of applications,including 3...Three-dimensional(3D)artificial metacrystals host rich topological phases,such as Weyl points,nodal rings,and 3D photonic topological insulators.These topological states enable a wide range of applications,including 3D robust waveguides,one-way fiber,and negative refraction of the surface wave.However,these carefully designed metacrystals are usually very complex,hindering their extension to nanoscale photonic systems.Here,we theoretically proposed and experimentally realized an ideal nodal ring in the visible region using a simple 1D photonic crystal.The TT-Berrry phase around the ring is manifested by a 2π reflection phase's winding and the resultant drumhead surface states.By breaking the inversion symmetry,the nodal ring can be gapped and the n-Berry phase would diffuse into a toroidal-shaped Berry flux,resulting in photonic ridge states(the 3D extension of quantum valley Hall states).Our results provide a simple and feasible platform for exploring 3D topological physics and its potential applications in nanophotonics.展开更多
基金supported by National Key Research and Development Program of China(Grant No.2022YFA1404304)National Natural Science Foundation of China(Grant Nos.62035016,12274475,12074443,62105200)+1 种基金Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2023B1515040023,2023B1515020072)Fundamental Research Funds for the Central Universities,Sun Yat-sen University(23lgbj021,23ptpy01)。
文摘3-dB couplers,which are commonly used in photonic integrated circuits for on-chip information processing,precision measurement,and quantum computing,face challenges in achieving robust performance due to their limited 3-dB bandwidths and sensitivity to fabrication errors.To address this,we introduce topological physics to nanophotonics,developing a framework for topological 3-dB couplers.These couplers exhibit broad working wavelength range and robustness against fabrication dimensional errors.By leveraging valley-Hall topology and mirror symmetry,the photonic-crystal-slab couplers achieve ideal 3-dB splitting characterized by a wavelength-insensitive scattering matrix.Tolerance analysis confirms the superiority on broad bandwidth of 48 nm and robust splitting against dimensional errors of 20 nm.We further propose a topological interferometer for on-chip distance measurement,which also exhibits robustness against dimensional errors.This extension of topological principles to the fields of interferometers,may open up new possibilities for constructing robust wavelength division multiplexing,temperature-drift-insensitive sensing,and optical coherence tomography applications.
基金This work was supported by National Natural Science Foundation of China(Grant Nos.11874435,62035016,12074443,and 11904421)Guangdong Basic and Applied Basic Research Foundation(Grant No.20198151502036)+2 种基金Natural Science Foundation of Guangdong Province(Grant No.20188030308005)Guangzhou Science,Technology and Innovation Commission(Grant Nos.201904010223 and 202102020693)Fundamental Research Funds for the Central Universities(Grant No.20lgzd29,20lgjc05,and 2021qntd27).
文摘Three-dimensional(3D)artificial metacrystals host rich topological phases,such as Weyl points,nodal rings,and 3D photonic topological insulators.These topological states enable a wide range of applications,including 3D robust waveguides,one-way fiber,and negative refraction of the surface wave.However,these carefully designed metacrystals are usually very complex,hindering their extension to nanoscale photonic systems.Here,we theoretically proposed and experimentally realized an ideal nodal ring in the visible region using a simple 1D photonic crystal.The TT-Berrry phase around the ring is manifested by a 2π reflection phase's winding and the resultant drumhead surface states.By breaking the inversion symmetry,the nodal ring can be gapped and the n-Berry phase would diffuse into a toroidal-shaped Berry flux,resulting in photonic ridge states(the 3D extension of quantum valley Hall states).Our results provide a simple and feasible platform for exploring 3D topological physics and its potential applications in nanophotonics.
