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Tutorial aims to make nonlinear spectroscopy technique more accessible outside of physics

JAN 21, 2022
Introductory paper explains vibrational sum frequency generation, which can be used to investigate the interfaces between bulk material, in a qualitative, intuitive manner.
Tutorial aims to make nonlinear spectroscopy technique more accessible outside of physics internal name

Tutorial aims to make nonlinear spectroscopy technique more accessible outside of physics lead image

The behavior of many macroscopic systems is often dictated in part by the critical molecular processes that occur at the interfaces between bulk media. Studying such interfaces, however, remains challenging for linear optical spectroscopies such as infrared and Raman spectroscopy.

Pickering et al. have written a tutorial for beginners looking to probe these interfaces with nonlinear vibrational sum frequency generation (VSFG) spectroscopy. By presenting the fundamental theory of VSFG spectroscopy with a focus on qualitative, intuitive explanations, the authors hope the tutorial will allow investigators without a rigorous formal background in optical physics or nonlinear spectroscopy to become conversant in the technique.

“I felt like a lot of the existing introductory material on VSFG was very physics-focused and quite mathematical,” author James Pickering said. “This was fine for me, as I have a chemical physics background, but a lot of people using SFG are from life sciences backgrounds, and so those existing resources might be inaccessible.”

When it comes to studying interphases between bulk materials, linear optical spectroscopy is often hampered by the bulk phases dominating the spectra and masking details about the interface itself.

“Through the magic of nonlinear optics, we can focus in on only the molecules that are present at the surface of the sample,” Pickering said. “In slightly more detail, we can essentially record an infrared spectrum of molecules at an interface.”

Pickering hopes the tutorial will inspire others to pen articles aimed at helping other disciplines understand techniques in a more approachable way.

Source: “Tutorials in vibrational sum frequency generation spectroscopy I: The foundations,” by James D. Pickering, Mikkel Bregnhøj, Adam S. Chatterley, Mette H. Rasmussen, Kris Strunge, and Tobias Weidner, Biointerphases (2022). The article can be accessed at https://doi.org/10.1116/6.0001401 .

This paper is part of the Tutorials in Sum-Frequency Generation Spectroscopy Collection, learn more here .

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