Synchrotron infrared nano-spectroscopy and -imaging

Abstract

Infrared (IR) spectroscopy has evolved into a powerful analytical technique to probe molecular and lattice vibrations, low-energy electronic excitations and correlations, and related collective surface plasmon, phonon, or other polaritonic resonances. In combination with scanning probe microscopy, near-field infrared nano-spectroscopy and -imaging techniques have recently emerged as a frontier in imaging science, enabling the study of complex heterogeneous materials with simultaneous nanoscale spatial resolution and chemical and quantum state spectroscopic specificity. Here, we describe synchrotron infrared nano-spectroscopy (SINS), which takes advantage of the low-noise, broadband, high spectral irradiance, and coherence of synchrotron infrared radiation for near-field infrared measurements across the mid-to far-infrared with nanometer spatial resolution. This powerful combination provides a qualitatively new form of broadband spatio-spectral analysis of nanoscale, mesoscale, and surface phenomena that were previously difficult to study with IR techniques, or even any form of microspectroscopy in general. We review the development of SINS, describe its technical implementations, and highlight selected examples representative of the rapidly growing range of 2 applications in physics, chemistry, biology, materials science, geology, and atmospheric and space sciences.

Exploring few and single layer CrPS4 with near-field infrared spectroscopy

“…Currently, the achievable spatial resolution at the Advance Light Source, Lawrence Berkeley National Laboratory is on the order of 20 × 20 nm 2 , and the frequency window is 330-4000 cm −1 . The low frequency range from 330 to 700 cm −1 is well suited for work on chalcogenides [40,42,44]. Figure 1(b) shows a schematic view of the near-field process.…”

Probing nanoparticle substrate interactions with synchrotron infrared nanospectroscopy: Coupling gold nanorod Fabry-Pérot resonances with SiO2 and h−BN phonons

“…The rich IR spectral content of the ALS allows the response of a sample to be simultaneously collected at all IR frequencies to which available photon detectors are sensitive. The current ALS SINS instrument system is capable of ∼0.5 meV spectral resolution that is considerably better than the ∼5 meV resolution of STEM EELS such that, taken together with the 25 nm spatial resolution provided by the AFM tip, SINS is a uniquely powerful technique with which to probe nanostructures, especially those with narrow resonances, in the mid-IR region [47][48][49][50][51][52][53][54][55][56].…”

Nano‐FTIR Investigation of the CM Chondrite Allan Hills 83100

“…Demodulation of the initial signal produces both an amplitude and a phase spectrum. These spectra are approximately analogous to the reflectance and absorbance spectra of typical far-field FTIR measurement (Bechtel et al, 2020), respectively. As such, we will make frequent comparisons between amplitude-reflectance and phase-absorbance in this work.…”