A type of combined optical fiber interferometric acoustic emission sensor is proposed. The sensor can be independent on the laser source and make light interference by matching the lengths of two arms,so it can be use...A type of combined optical fiber interferometric acoustic emission sensor is proposed. The sensor can be independent on the laser source and make light interference by matching the lengths of two arms,so it can be used to monitor the health of large structure. Theoretical analyses indicate that the system can be equivalent to the Michelson interferometer with two optical fiber loop reflectors,and its sensitivity has been remarkably increased because of the decrease of the losses of light energy. PZT is powered by DC regulator to control the operating point of the system,so the system can accurately detect feeble vibration which is generated by ultrasonic waves propagating on the surface of solid. The amplitude and the frequency of feeble vibration signal are obtained by detecting the output light intensity of interferometer and using Fourier transform technique. The results indicate that the system can be used to detect the acoustic emission signals by the frequency characteristics.展开更多
The recent discovery and realizations of higher-order topological insulators enrich the fundamental studies on topological phases.Here,we report three-dimensional(3D)wave-steering capabilities enabled by topological b...The recent discovery and realizations of higher-order topological insulators enrich the fundamental studies on topological phases.Here,we report three-dimensional(3D)wave-steering capabilities enabled by topological boundary states at three different orders in a 3D phononic crystal with nontrivial bulk topology originated from the synergy of mirror symmetry of the unit cell and a non-symmorphic glide symmetry of the lattice.The multitude of topological states brings diverse possibilities of wave manipulations.Through judicious engineering of the boundary modes,we experimentally demonstrate two functionalities at different dimensions:2D negative refraction of sound wave enabled by a firstorder topological surface state with negative dispersion,and a 3D acoustic interferometer leveraging on second-order topological hinge states.Our work showcases that topological modes at different orders promise diverse wave steering applications across different dimensions.展开更多
基金the Fundamental Research Foundation of Harbin Engineering University, (grant number HEUF 04017)
文摘A type of combined optical fiber interferometric acoustic emission sensor is proposed. The sensor can be independent on the laser source and make light interference by matching the lengths of two arms,so it can be used to monitor the health of large structure. Theoretical analyses indicate that the system can be equivalent to the Michelson interferometer with two optical fiber loop reflectors,and its sensitivity has been remarkably increased because of the decrease of the losses of light energy. PZT is powered by DC regulator to control the operating point of the system,so the system can accurately detect feeble vibration which is generated by ultrasonic waves propagating on the surface of solid. The amplitude and the frequency of feeble vibration signal are obtained by detecting the output light intensity of interferometer and using Fourier transform technique. The results indicate that the system can be used to detect the acoustic emission signals by the frequency characteristics.
基金supported by the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under Award No. OSR-2016-CRG5-2950KAUST Baseline Research Fund BAS/1/1626-01-01+3 种基金supported by the Hong Kong Research Grants Council (GRF 12302420, 12300419, ECS 22302718, CRF C6013-18G)the National Natural Science Foundation of China via the Excellent Young Scientist Scheme (Hong Kong & Macao) (#11922416)the Youth Program (#11802256)Hong Kong Baptist University (RC-SGT2/18-19/ SCI/006)。
文摘The recent discovery and realizations of higher-order topological insulators enrich the fundamental studies on topological phases.Here,we report three-dimensional(3D)wave-steering capabilities enabled by topological boundary states at three different orders in a 3D phononic crystal with nontrivial bulk topology originated from the synergy of mirror symmetry of the unit cell and a non-symmorphic glide symmetry of the lattice.The multitude of topological states brings diverse possibilities of wave manipulations.Through judicious engineering of the boundary modes,we experimentally demonstrate two functionalities at different dimensions:2D negative refraction of sound wave enabled by a firstorder topological surface state with negative dispersion,and a 3D acoustic interferometer leveraging on second-order topological hinge states.Our work showcases that topological modes at different orders promise diverse wave steering applications across different dimensions.
