  Deep learning is known to be data-hungry, which hinders its application in
many areas of science when datasets are small. Here, we propose to use transfer
learning methods to migrate knowledge between different physical scenarios and
significantly improve the prediction accuracy of artificial neural networks
trained on a small dataset. This method can help reduce the demand for
expensive data by making use of additional inexpensive data. First, we
demonstrate that in predicting the transmission from multilayer photonic film,
the relative error rate is reduced by 46.8% (26.5%) when the source data comes
from 10-layer (8-layer) films and the target data comes from 8-layer (10-layer)
films. Second, we show that the relative error rate is decreased by 22% when
knowledge is transferred between two very different physical scenarios:
transmission from multilayer films and scattering from multilayer
nanoparticles. Finally, we propose a multi-task learning method to improve the
performance of different physical scenarios simultaneously in which each task
only has a small dataset.
