Design and characterization of a high signal-to-noise ratio 40 kHz multiplex sum-frequency generation vibrational spectroscopy setup

Interfaces and surfaces play a crucial role in nature as well as in numerous technological processes. Sum frequency generation vibrational (SFG-VS) infrared spectroscopy has emerged as an exemplary technique for their investigation. It offers high sensitivity and intrinsic surface specificity, eliminating background from bulk material. We present a SFG-VS spectrometer optimized for high sensitivity and low integration time, achieved through high repetition-rate, which also incorporates techniques for effective suppression of non-resonant background contributions. This robust and versatile implementation shall contribute to the advancement of SFG-VS spectroscopy to a standard method in fundamental and industrial research.