Damped acoustic systems have a limited quality factor due to intrinsic loss.By introducing gain elements,a method to enhance the quality factor of damped systems is proposed based on the concept of bound states in the...Damped acoustic systems have a limited quality factor due to intrinsic loss.By introducing gain elements,a method to enhance the quality factor of damped systems is proposed based on the concept of bound states in the continuum(BICs).The acoustic model under study is a two-port waveguide system installed with two side Helmholtz resonators connected by a coupling tube.Based on the temporal coupled-mode theory,a Hamiltonian matrix with both intrinsic and radiation losses is used to characterize the resonance behavior of the coupled resonators.To achieve a high quality factor,acoustic gain is introduced to compensate the intrinsic loss,leading the Hamiltonian parameters toward a quasi-BIC condition.Numerical simulation demonstrates a gain-assisted and quasi-BIC-supported extremely high quality factor in damped acoustic systems.The concept is further utilized to design a sensor model for particle size detection.The enhanced sensing performance due to high quality factors is numerically demonstrated.The findings suggest potential applications in acoustic sensing and detection devices.展开更多
The emergent metagrating,with its unique and flexible beam shaping capabilities,offers new paths to efficient modulation of acoustic waves.In this work,an acoustic metagrating is demonstrated for high-efficiency and w...The emergent metagrating,with its unique and flexible beam shaping capabilities,offers new paths to efficient modulation of acoustic waves.In this work,an acoustic metagrating is demonstrated for high-efficiency and wide-angle anomalous refraction.It is shown that the normal reflection and transmission can be totally suppressed by properly modulating the amplitude and phase characteristics of the metagrating supercells for high-efficiency anomalous refraction.The anomalous refraction behavior is achieved in the wide range of incident angles from 28°to 78°,and the efficiency of-1st order diffraction is higher than 90%by finely designing the metagrating structure.The anomalous refraction behaviors are verified experimentally at incidence angle of 28°,45°,and 78°,respectively.The demonstrated metagrating is anticipated to possess efficient wide-angle composite wavefront engineering applications in such fields as communications.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12225203,11622215,and 11872111)the 111 Project(Grant No.B16003).
文摘Damped acoustic systems have a limited quality factor due to intrinsic loss.By introducing gain elements,a method to enhance the quality factor of damped systems is proposed based on the concept of bound states in the continuum(BICs).The acoustic model under study is a two-port waveguide system installed with two side Helmholtz resonators connected by a coupling tube.Based on the temporal coupled-mode theory,a Hamiltonian matrix with both intrinsic and radiation losses is used to characterize the resonance behavior of the coupled resonators.To achieve a high quality factor,acoustic gain is introduced to compensate the intrinsic loss,leading the Hamiltonian parameters toward a quasi-BIC condition.Numerical simulation demonstrates a gain-assisted and quasi-BIC-supported extremely high quality factor in damped acoustic systems.The concept is further utilized to design a sensor model for particle size detection.The enhanced sensing performance due to high quality factors is numerically demonstrated.The findings suggest potential applications in acoustic sensing and detection devices.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2023YFB3811400 and 2022YFB3806000)the National Natural Science Foundation of China(Grant No.12074314)+1 种基金the Science and Technology New Star Program of Shaanxi Province,China(Grant No.2023KJXX-148)the Fundamental Research Funds for the Central Universities。
文摘The emergent metagrating,with its unique and flexible beam shaping capabilities,offers new paths to efficient modulation of acoustic waves.In this work,an acoustic metagrating is demonstrated for high-efficiency and wide-angle anomalous refraction.It is shown that the normal reflection and transmission can be totally suppressed by properly modulating the amplitude and phase characteristics of the metagrating supercells for high-efficiency anomalous refraction.The anomalous refraction behavior is achieved in the wide range of incident angles from 28°to 78°,and the efficiency of-1st order diffraction is higher than 90%by finely designing the metagrating structure.The anomalous refraction behaviors are verified experimentally at incidence angle of 28°,45°,and 78°,respectively.The demonstrated metagrating is anticipated to possess efficient wide-angle composite wavefront engineering applications in such fields as communications.
