Nanoscale Spatial Resolution in Far-Field Raman Imaging Using Hyperspectral Unmixing in Combination with Positivity Constrained Super-Resolution

Abstract

This work introduces hyper-resolution (HyRes), a numerical approach for spatial resolution enhancement that combines hyperspectral unmixing and super-resolution image restoration (SRIR). HyRes yields a substantial increase in spatial resolution of Raman spectroscopy while simultaneously preserving the undistorted spectral information. The resolving power of this technique is demonstrated on Raman spectroscopic data from a polymer nanowire sample. Here, we demonstrate an achieved resolution of better than 14 nm, a more than eightfold improvement on single-channel image-based SRIR and [Formula: see text] better than regular far-field Raman spectroscopy, and comparable to near-field probing techniques.

Simulated Raman spectra of bulk and low-dimensional phosphorus allotropes

“…In this context Raman spectroscopy plays a pivotal role, as a powerful, non-destructive, and sensitive tool able in principle to differentiate all of the bulk phases described above 22 . Although traditionally a bulk characterization technique, significant advances in both sample manipulation, mapping, super resolution and signal deconvolution 23,24 mean that Raman spectroscopy can now also be increasingly applied to individual nano-objects. In order to make the link between experimental Raman spectra and underlying atomic structure, accurate spectral modelling is required.…”