Inspired by the three-dimensional design of flow passages in turbomachinery,this study proposes the concept of integrated passage design.The capability of adjoint method for efficient optimization and the flexibility ...Inspired by the three-dimensional design of flow passages in turbomachinery,this study proposes the concept of integrated passage design.The capability of adjoint method for efficient optimization and the flexibility of the parameterization method based on extended free-form defor-mation have been considered to develop a feasible approach to design an integrated passage.This concept was applied to redesign a typical transonic fan,Rotor 67,and the results were analyzed by CFX.It is shown that the passage was adequately adjusted in all three dimensions and reduced the strength of shock wave and wake-induced flow.In particular,the secondary flow was appropriately reorganized and the corner separation was well controlled in the end wall region,leading to signif-icant improvements in adiabatic efficiency and diffusion.展开更多
Planar metasurfaces with both chirality and high quality(Q)factors have important applications in many fields.A chiral metasurface empowered by a bound state in the continuum(BIC)can provide a perfect solution to this...Planar metasurfaces with both chirality and high quality(Q)factors have important applications in many fields.A chiral metasurface empowered by a bound state in the continuum(BIC)can provide a perfect solution to this problem.However,the metasurface design method based on physical intuition requires a substantial amount of computational resources,and the limited design parameters of meta-atoms restrict metasurfaces from achieving optimal optical performance.Here,we apply an inverse design method based on adjoint topological optimization to automatically alter the refractive index distribution of the metasurface,thereby maximizing the chirality of the BIC metasurface.Through this inverse design approach,chiral BIC metasurfaces with 3D intrinsic chirality at the target wavelength are designed and fabricated.To demonstrate the versatility of the proposed inverse design method,the metasurfaces with specific elliptic polarization states are designed.The inverse design method we propose provides an effective solution for the efficient design of chiral BIC metasurfaces.展开更多
Independent manipulation of transmitted and reflected light fields is a key technology for the realization of multifunctional optical applications,which can be implemented based on multilayered plasmonic or supercell ...Independent manipulation of transmitted and reflected light fields is a key technology for the realization of multifunctional optical applications,which can be implemented based on multilayered plasmonic or supercell subwavelength structures.However,the former is not suitable for the optical bands,while the latter is insufficient in generating large phase gradients.Here,an adjoint-optimization-based inverse design methodology is proposed,which utilizes the polarization-selective local interference between individual meta-atoms and enables monolayer dielectric metasurfaces to decouple the wavefront of transmitted and reflected optical fields.Moreover,this methodology serves to mitigate the aperiodic electromagnetic crosstalk inherent between adjacent meta-atoms,consequently leading to a significant enhancement in the performance of meta-devices.We analyzed the physical mechanism of adjoint optimization and proposed the concept of phase factors,highlighting their importance in the rapid inverse design of meta-devices—an aspect often overlooked in previous research.To demonstrate the feasibility and robustness of our method,we optimize monolayer metasurfaces with different initial structures.These devices efficiently focus and deflect x-linearly and y-linearly polarized incident light in transmission and reflection spaces,respectively.Overall,this methodology holds immense potential for designing multifunctional,high-performing metasurfaces that meet multiple constraints,opening up broad prospects for applications.展开更多
基金supported by the National Science and Technology Major Project of China(Nos.2017-II-0006-0020,J2019-II-0003-0023).
文摘Inspired by the three-dimensional design of flow passages in turbomachinery,this study proposes the concept of integrated passage design.The capability of adjoint method for efficient optimization and the flexibility of the parameterization method based on extended free-form defor-mation have been considered to develop a feasible approach to design an integrated passage.This concept was applied to redesign a typical transonic fan,Rotor 67,and the results were analyzed by CFX.It is shown that the passage was adequately adjusted in all three dimensions and reduced the strength of shock wave and wake-induced flow.In particular,the secondary flow was appropriately reorganized and the corner separation was well controlled in the end wall region,leading to signif-icant improvements in adiabatic efficiency and diffusion.
基金National Key Research and Development Program of China(2022YFB4600204)National Natural Science Foundation of China(12104046,62105024,61775019,U21A20140)。
文摘Planar metasurfaces with both chirality and high quality(Q)factors have important applications in many fields.A chiral metasurface empowered by a bound state in the continuum(BIC)can provide a perfect solution to this problem.However,the metasurface design method based on physical intuition requires a substantial amount of computational resources,and the limited design parameters of meta-atoms restrict metasurfaces from achieving optimal optical performance.Here,we apply an inverse design method based on adjoint topological optimization to automatically alter the refractive index distribution of the metasurface,thereby maximizing the chirality of the BIC metasurface.Through this inverse design approach,chiral BIC metasurfaces with 3D intrinsic chirality at the target wavelength are designed and fabricated.To demonstrate the versatility of the proposed inverse design method,the metasurfaces with specific elliptic polarization states are designed.The inverse design method we propose provides an effective solution for the efficient design of chiral BIC metasurfaces.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFB2805800)the National Natural Science Foundation of China(Grant Nos.62175242,and U20A20217)the Sichuan Science and Technology Program(Grant No.2021ZYCD002)。
文摘Independent manipulation of transmitted and reflected light fields is a key technology for the realization of multifunctional optical applications,which can be implemented based on multilayered plasmonic or supercell subwavelength structures.However,the former is not suitable for the optical bands,while the latter is insufficient in generating large phase gradients.Here,an adjoint-optimization-based inverse design methodology is proposed,which utilizes the polarization-selective local interference between individual meta-atoms and enables monolayer dielectric metasurfaces to decouple the wavefront of transmitted and reflected optical fields.Moreover,this methodology serves to mitigate the aperiodic electromagnetic crosstalk inherent between adjacent meta-atoms,consequently leading to a significant enhancement in the performance of meta-devices.We analyzed the physical mechanism of adjoint optimization and proposed the concept of phase factors,highlighting their importance in the rapid inverse design of meta-devices—an aspect often overlooked in previous research.To demonstrate the feasibility and robustness of our method,we optimize monolayer metasurfaces with different initial structures.These devices efficiently focus and deflect x-linearly and y-linearly polarized incident light in transmission and reflection spaces,respectively.Overall,this methodology holds immense potential for designing multifunctional,high-performing metasurfaces that meet multiple constraints,opening up broad prospects for applications.
