The simultaneous opening of photonic and phononic bandgaps is essential for achieving strong confinement and effective coupling of light and sound in phoxonic crystals. These dual bandgaps enableco-localized cavity and waveguide modes, which are key to high-performance optomechanical devices such as sensors, modulators, and acousto-optic circuits. However, due to the differing physical mechanisms of optical and elastic waves, achieving balanced optimization of both bandgaps remains a major challenge.
The team led by Prof. Zhuang proposed a GA-SIMP two-stage topology optimization method, where a genetic algorithm is employed to generate an initial design, followed by SIMP method for refinement and convergence to an optimal metamaterial design. This approach combines the global search capability of GA with the computational efficiency and precision of SIMP, addressing the competing requirements of dual bandgap optimization in phoxonic crystals—a problem not effectively solved by standalone methods. While both GA and SIMP are well-established methods individually, their strategic combination in our framework establishes the first attempt at phoxonic crystal design.
This study was the collaborative outcome by researchers from the CSST team of IOP at Leibniz University Hannover, and colleagues from France, Prof. Bahram Djafari-Rouhani and Prof. Yan Pennec from the University of Lille. Prof. Djafari-Rouhani is a pioneer in the field of phononic crystals and metamaterials. Prof. Pennec focuses on the theoretical and numerical study of wave propagation in phononic, plasmonic, and photonic nanostructures.
Authors:
Original publication:
Bin Li, S.S. Nanthakumar, Yan Pennec, Bahram Djafari-Rouhani, Xiaoying Zhuang. Topology optimization of phoxonic crystals for maximizing dual bandgaps using GA-SIMP method. International Journal of Mechanical Sciences, 2025. DOI: 10.1016/j.ijmecsci.2025.110359.
