Transfer Learning for Modeling Plasmonic Nanowire Waveguides

Retrieving waveguiding properties of plasmonic metal nanowires (MNWs) through numerical simulations is time- and computational-resource-consuming, especially for those with abrupt geometric features and broken symmetries. Deep learning provides an alternative approach but is challenging to use due to inadequate generalization performance and the requirement of large sets of training data. Here, we overcome these constraints by proposing a transfer learning approach for modeling MNWs under the guidance of physics. We show that the basic knowledge of plasmon modes can first be learned from free-standing circular MNWs with computationally inexpensive data, and then reused to significantly improve performance in predicting waveguiding properties of MNWs with various complex configurations, enabling much smaller errors (similar to 23-61% reduction), less trainable parameters (similar to 42% reduction), and smaller sets of training data (similar to 50-80% reduction) than direct learning. Compared to numerical simulations, our model reduces the computational time by five orders of magnitude. Compared to other non-deep learning methods, such as the circular-area-equivalence approach and the diagonal-circle approximation, our approach enables not only much higher accuracies, but also more comprehensive characterizations, offering an effective and efficient framework to investigate MNWs that may greatly facilitate the design of polaritonic components and devices.

Automated summary

In this study, we propose a transfer learning approach for modeling metal nanowires and predicting their waveguiding properties. With the guidance of physics, basic knowledge of plasmon modes is first learned from circular nanowires, which is then transferred to improve the performance of predicting waveguiding properties of nanowires with complex configurations. Our approach reduces errors, trainable parameters, and training data required compared to direct learning methods, and significantly reduces computational time. Compared to non-deep learning methods, our approach offers higher accuracies and more comprehensive characterizations, making it an effective and efficient framework for investigating metal nanowires.