Collective lattice and plasmonic resonances in the enhancement of circular dichroism in disk–rod metasurface
Journal of Applied Physics 133, 043103 (2023); https://doi.org/10.1063/5.0124798
Compact planar photonic elements serving for efficient control over the polarization of light are of paramount importance in photonics. Here, we propose a design of a chiral periodic metasurface based on plasmonic nanodisks and nanorods arranged asymmetrically in a unit cell. Using the finite-difference time-domain (FDTD) analysis, we show that the collective lattice resonance harnessed by the diffraction coupling of the plasmonic unit cells is the heart of the revealed resonant 38% circular dichroism effect. The circular dichroism enhancement of the considered structure is improved using the deep-learning-assisted optimization of the metasurface design.
The .ipynb notebook presented here is used to construct and train a neural network for convenient FDTD data interpolation and analysis. The dataset is attached as a folder precise_data, with subfolders for input X (4 parameters of the unit cell) and corresponding output data Y (200 spectral points). To run the code it should be extracted in the same folder as the notebook.