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Inverse Design of a Dielectric Metasurface by the Spatial Coupled Mode Theory
Inverse Design of a Dielectric Metasurface by the Spatial Coupled Mode Theory
Modeling metasurfaces with high accuracy and efficiency is challenging because they have features smaller than the wavelength but sizes much larger than the wavelength. Full wave simulation is accurate but very slow. Popular design paradigms like locally periodic approximation (LPA) reduce the computational cost by neglecting, partially or fully, near-field interactions between meta-units and treating them in an isolated manner. The coupling between meta-units has been fully considered by applying the temporal coupled mode theory to model the metasurface. However, this method only works for resonance-based metasurfaces. To model the broadly studied dielectric metasurfaces based on the propagation of guided modes, we propose to model the whole system using a spatial coupled mode theory where the dielectric metasurface can be viewed as an array of truncated waveguides. An inverse design routine based on this model is then devised and applied to gain improvements over LPA in several scenarios, such as high numerical aperture lens, multiwavelength focusing, and suppression of coma aberrations. With its accuracy and efficiency, the proposed framework can be a powerful tool to improve the performance of dielectric metasurfaces on various tasks.
clock 2024-07-16 10:00:00 +0000
clock Zhicheng Wu, Xiaoyan Huang, Nanfang Yu, Zongfu Yu
Adjoint-Optimized Large Dielectric Metasurface for Enhanced Purcell Factor and Directional Photon Emission
Adjoint-Optimized Large Dielectric Metasurface for Enhanced Purcell Factor and Directional Photon Emission
Extracting photons efficiently from quantum sources, such as atoms, molecules, and quantum dots, is crucial for various nanophotonic systems used in quantum communication, sensing, and computation. To improve the performance of these systems, it is not only necessary to provide an environment that maximizes the number of optical modes, but it is also desirable to guide the extracted light toward specific directions. One way to achieve this goal is to use a large area metasurface that can steer the beam. Previous work has used small aperture devices that are fundamentally limited in their ability to achieve high directivity. This work proposes an adjoint-based topology optimization approach to design a large light extractor that can enhance the spontaneous decay rate of the embedded quantum transition and collimate the extracted photons. With the help of this approach, we present all-dielectric metasurfaces for a quantum transition emitting at λ = 600 nm. These metasurfaces achieve a broadband improvement of spontaneous emission compared to that in the vacuum, reaching a 10× enhancement at the design frequency. Furthermore, they can beam the extracted light into a narrow cone (±10°) along a desired direction that is predefined through their respective design process.
clock 2024-06-13 12:00:00 +0000
clock Erfan Khoram*, Zongfu Yu, and S. Ali Hassani Gangaraj
A solution-processed radiative cooling glass
A solution-processed radiative cooling glass
Passive daytime radiative cooling materials, capable of reducing building cooling energy by up to 60%, reflect sunlight and emit infrared radiation. The challenge lies in producing practical, durable structures. A recent publication in the Science magazine proposed the solution of using microporous glass composite with selective infrared emission and high solar reflectance, enhanced with aluminum oxide for sunlight scattering. This coating can lower temperatures by 3.5° to 4°C, even under high humidity. Remarkably, it maintains effectiveness under harsh conditions such as water, UV radiation, and extreme temperatures.
clock 2023-11-09 20:08:00 +0000
clock Xinpeng Zhao, Tangyuan Li, Hua Xie, He Liu, Lingzhe Wang, Yurui Qu, Stephanie C. Li, Shufeng Liu, Alexandra H. Brozena, Zongfu Yu, Jelena Srebric, Liangbing Hu
Anderson localization of electromagnetic waves in three dimensions
Anderson localization of electromagnetic waves in three dimensions
clock 2023-06-15 00:39:00 +0000
clock Alexey Yamilov, Sergey E. Skipetrov, Tyler W. Hughes, Momchil Minkov, Zongfu Yu, Hui Cao
The Application of Flow360 to the 7th Drag Prediction Workshop Cases
The Application of Flow360 to the 7th Drag Prediction Workshop Cases
Explore Flexcompute's innovative contribution to the 7th Drag Prediction Workshop, showcasing how our advanced Flow360 solver accurately predicts aircraft drag, pitching moment, and complex aerodynamic phenomena. Dive into the comparison of various RANS closures, and see how the SA-RC-QCR model outperforms in replicating experimental data trends.
clock 2023-06-12 19:40:00 +0000
clock Thomas Fitzgibbon, CJ Doolittle, Philippe Spalart, Qiqi Wang
Increasing the Q-contrast in large photonic crystal slab resonators using bound-states-in-continuum
Increasing the Q-contrast in large photonic crystal slab resonators using bound-states-in-continuum
clock 2023-05-03 14:30:00 +0000
clock Ming Zhou, Akhil Raj Kumar Kalapala, Mingsen Pan, Ricky Gibson, Kevin James Reilly, Thomas Rotter, Garnesh Balakrishnan, Robert Bedford, Weidong Zhou, and Shanhui Fan
REGENT Seaglider CFD Analysis with Flow360
REGENT Seaglider CFD Analysis with Flow360
clock 2023-03-02 08:00:00 +0000
clock Brett Peters, CJ Doolittle and Jim Bungener
Fundamental Studies Towards Rotor Simulations and Design
Fundamental Studies Towards Rotor Simulations and Design
clock 2023-02-09 15:08:39 +0000
clock Feilin Jia, Maks J Groom, Philippe Spalart and Qiqi Wang
An Application of the Flow360 Solver to the Hover Download Prediction Problem
An Application of the Flow360 Solver to the Hover Download Prediction Problem
clock 2023-02-09 15:06:55 +0000
clock Thomas Fitzgibbon, CJ Doolittle and Philippe Spalart
XV-15 Rotor Simulation in Flow360 using the Blade Element Theory
XV-15 Rotor Simulation in Flow360 using the Blade Element Theory
clock 2022-12-01 15:11:59 +0000
clock John Moore, Feilin Jia and Qiqi Wang
An Analysis of Modeling Sensitivity Effects for High Lift Predictions using the Flow360 CFD Solver
An Analysis of Modeling Sensitivity Effects for High Lift Predictions using the Flow360 CFD Solver
clock 2022-06-29 00:00:00 +0000
clock Thomas Fitzgibbon, Philippe Spalart and Jim Bungener and Qiqi Wang
Impact of the Propulsion Modeling Approach on High-Lift Force Predictions of Propeller-Blown Wings
Impact of the Propulsion Modeling Approach on High-Lift Force Predictions of Propeller-Blown Wings
clock 2022-06-27 00:00:00 +0000
clock Cecile Casses, Chris Courtin, Mark Drela, Thomas Fitzgibbon, Runda Ji, Maciej Skarysz, Philippe Spalart and Qiqi Wang
Rotor5: Rotor analysis under 5 hours using ultra-fast and high-fidelity CFD simulation and automatic meshing
Rotor5: Rotor analysis under 5 hours using ultra-fast and high-fidelity CFD simulation and automatic meshing
clock 2022-01-27 00:00:00 +0000
clock Runda Ji, Feilin Jia, Philippe Spalart, Zongfu Yu and Qiqi Wang
Assessment of Detached Eddy Simulation and Sliding Mesh Interface in Predicting Tiltrotor Performance in Helicopter and Airplane Modes
Assessment of Detached Eddy Simulation and Sliding Mesh Interface in Predicting Tiltrotor Performance in Helicopter and Airplane Modes
clock 2022-01-27 00:00:00 +0000
clock Feilin Jia, John Moore and Qiqi Wang
Aerodynamic Risk Assessment using Parametric, Three-Dimensional Unstructured, High-Fidelity CFD and Adaptive Sampling
Aerodynamic Risk Assessment using Parametric, Three-Dimensional Unstructured, High-Fidelity CFD and Adaptive Sampling
clock 2021-09-07 00:00:00 +0000
clock Runda Ji and Qiqi Wang