Sum frequency generation (SFG) vibrational spectroscopy provides detailed information about the structure, function, and interactions of molecules through the analysis of the vibrations of atoms.

Optical layout of SFG spectrometer.
In recent article on PhotonicsViews, Ekspla R&D team members accompanied by colleagues from other organizations revealed main principles of vibrational spectroscopy, possibilities to tailor for specific applications as well as one of the hottest applications – research of materials employed in photovoltaic applications.
The SFG spectrometer developed by Ekspla scientists and engineers is a nonlinear spectrometry instrument, convenient for everyday use. Ekspla manufactures SFG spectrometers, which are used by chemists, biologists, material scientists, and physicists. The spectrometer has many features that help to set up measurements and to make successful vibrational spectroscopy studies. For chemical and biochemical laboratories, this makes the Ekspla SFG spectrometer a reliable workhorse with a broad spectral region, automatically tuned, a high spectral resolution, and easily controlled adjustment of polarization optics.
Article: https://onlinelibrary.wiley.com/doi/epdf/10.1002/phvs.202100041