18 research outputs found
Predictability of localized plasmonic responses in nanoparticle assemblies
Design of nanoscale structures with desired nanophotonic properties are key
tasks for nanooptics and nanophotonics. Here, the correlative relationship
between local nanoparticle geometries and their plasmonic responses is
established using encoder-decoder neural networks. In the im2spec network, the
correlative relationship between local particle geometries and local spectra is
established via encoding the observed geometries to a small number of latent
variables and subsequently decoding into plasmonic spectra; in the spec2im
network, the relationship is reversed. Surprisingly, these reduced descriptions
allow high-veracity predictions of the local responses based on geometries for
fixed compositions and chemical states of the surface. The analysis of the
latent space distributions and the corresponding decoded and closest (in latent
space) encoded images yields insight into the generative mechanisms of
plasmonic interactions in the nanoparticle arrays. Ultimately, this approach
creates a path toward determining configurations that can yield the spectrum
closest to the desired one, paving the way for stochastic design of
nanoplasmonic structures
A dynamic Bayesian optimized active recommender system for curiosity-driven Human-in-the-loop automated experiments
Optimization of experimental materials synthesis and characterization through
active learning methods has been growing over the last decade, with examples
ranging from measurements of diffraction on combinatorial alloys at
synchrotrons, to searches through chemical space with automated synthesis
robots for perovskites. In virtually all cases, the target property of interest
for optimization is defined apriori with limited human feedback during
operation. In contrast, here we present the development of a new type of human
in the loop experimental workflow, via a Bayesian optimized active recommender
system (BOARS), to shape targets on the fly, employing human feedback. We
showcase examples of this framework applied to pre-acquired piezoresponse force
spectroscopy of a ferroelectric thin film, and then implement this in real time
on an atomic force microscope, where the optimization proceeds to find
symmetric piezoresponse amplitude hysteresis loops. It is found that such
features appear more affected by subsurface defects than the local domain
structure. This work shows the utility of human-augmented machine learning
approaches for curiosity-driven exploration of systems across experimental
domains. The analysis reported here is summarized in Colab Notebook for the
purpose of tutorial and application to other data:
https://github.com/arpanbiswas52/varTBOComment: 7 figures in main text, 3 figures in Supp Materia
Deep Learning for Automated Experimentation in Scanning Transmission Electron Microscopy
Machine learning (ML) has become critical for post-acquisition data analysis
in (scanning) transmission electron microscopy, (S)TEM, imaging and
spectroscopy. An emerging trend is the transition to real-time analysis and
closed-loop microscope operation. The effective use of ML in electron
microscopy now requires the development of strategies for microscopy-centered
experiment workflow design and optimization. Here, we discuss the associated
challenges with the transition to active ML, including sequential data analysis
and out-of-distribution drift effects, the requirements for the edge operation,
local and cloud data storage, and theory in the loop operations. Specifically,
we discuss the relative contributions of human scientists and ML agents in the
ideation, orchestration, and execution of experimental workflows and the need
to develop universal hyper languages that can apply across multiple platforms.
These considerations will collectively inform the operationalization of ML in
next-generation experimentation.Comment: Review Articl