Self-driving lab discovers principles for steering spontaneous emission
<|reference_start|>Self-driving lab discovers principles for steering spontaneous emission: We developed an autonomous experimentation platform to accelerate interpretable scientific discovery in ultrafast nanophotonics, targeting a novel method to steer spontaneous emission from reconfigurable semiconductor metasurfaces. Controlling spontaneous emission is crucial for clean-energy solutions in illumination, thermal radiation engineering, and remote sensing. Despite the potential of reconfigurable semiconductor metasurfaces with embedded sources for spatiotemporal control, achieving arbitrary far-field control remains challenging. Here, we present a self-driving lab (SDL) platform that addresses this challenge by discovering the governing equations for predicting the far-field emission profile from light-emitting metasurfaces. We discover that both the spatial gradient (grating-like) and the curvature (lens-like) of the local refractive index are key factors in steering spontaneous emission. The SDL employs a machine-learning framework comprising: (1) a variational autoencoder for generating complex spatial refractive index profiles, (2) an active learning agent for guiding experiments with real-time closed-loop feedback, and (3) a neural network-based equation learner to uncover structure-property relationships. The SDL demonstrated a four-fold enhancement in peak emission directivity (up to 77%) over a 72{\deg} field of view within ~300 experiments. Our findings reveal that combinations of positive gratings and lenses are as effective as negative lenses and gratings for all emission angles, offering a novel strategy for controlling spontaneous emission beyond conventional Fourier optics.<|reference_end|>
@article{desai2024self-driving,
    title={Self-driving lab discovers principles for steering spontaneous emission},
    author={Saaketh Desai, Sadhvikas Addamane, Jeffery Y. Tsao, Igal Brener, Remi
  Dingreville, Prasad P. Iyer},
    journal={arXiv preprint arXiv:2407.16083},
    year={2024},
    archivePrefix={arXiv},
    eprint={2407.16083},
    primaryClass={physics.optics cond-mat.mtrl-sci cs.LG}
}