Step-scan interferometry for high-fidelity hyperspectral nanoscopy

TL;DR

This paper introduces a step-scan interferometry method for nano-FTIR that enhances spatial fidelity and dataset size, improving nanoscale material characterization and enabling machine learning applications.

Contribution

The authors develop a novel nano-FTIR measurement technique using step-scan interferometry and image registration for improved accuracy and larger data collection.

Findings

Superior spatial fidelity demonstrated in photonics research

Enables collection of larger hyperspectral datasets

Facilitates machine learning for nanoscale heterogeneity analysis

Abstract

Fourier transform infrared nanospectroscopy (nano-FTIR) is a novel, increasingly adopted characterization method that leverages decades of established knowledge in infrared spectroscopy at the nanoscale. It opens up new possibilities in the characterization of composite materials and nanophotonic systems. Besides the rapid adoption and new possibilities, the nanoscale nature of these measurements poses new challenges for infrared spectroscopy. The current implementations of hyperspectral image acquisition at high spatial resolution suffer from significant artifacts due to thermal instabilities, which heavily affect positioning. As a result, the spatial and spectral fidelity of the measurements can be unreliable for long acquisitions. Here, we propose a new nano-FTIR measurement methodology based on step-scan interferometry and image registration. We demonstrate that the method provides superior spatial fidelity for photonics research and enables the collection of larger datasets, paving the way for bringing machine learning to characterize nanoscale heterogeneity.