# Photothermal Polarimetric Nanoscopy: An Emerging Technique for Fingerprinting Minerals of Extraterrestrial Origin

## TL;DR

A new technique called photothermal polarimetric nanoscopy allows scientists to study the composition of extraterrestrial minerals at a very small scale without damaging them.

## Contribution

The paper introduces photothermal polarimetric nanoscopy as a novel method for noninvasive nanoscale mineral analysis.

## Key findings

- The technique enables noninvasive infrared fingerprint spectra of minerals at the nanoscale.
- Polarization-dependent analysis can provide structural information about nanocrystallites in solid matrices.

## Abstract

Nanospectroscopic investigations of the mineralogical
composition
of materials returned via sample-return missions are crucial for our
understanding of the origin and evolution of planetary objects in
our Solar System. Here, we show that the emerging technique of photothermal
polarimetric nanoscopy, a variant of atomic force microscopy-based
infrared spectroscopy, enables one to derive infrared fingerprint
spectra of minerals noninvasively on the nanoscale. Besides the spatially
resolved identification of specific minerals and mineral phases, the
evaluation of the polarization dependence of the photoinduced nanomechanical
response, in combination with optical reference data, may allow the
deduction of valuable structural information on individual nanocrystallites
or grains embedded in solid matrices.