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Updated: Jan 28, 2026

Author Spotlight: Unveiling the Potential of VSFG Microscopy in Studying Mesoscopically Heterogeneous Self-Assembled Structures
Published on: December 1, 2023
Flexible high-resolution broadband sum-frequency generation vibrational spectroscopy for intrinsic spectral line
Ruidan Zhang1, Xingxing Peng1, Zhirun Jiao1
1State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, People's Republic of China.
Abstract:
The difficulty in achieving high spectral resolution and accurate line shape in sum-frequency generation vibrational spectroscopy (SFG-VS) has restricted its use in applications requiring precise detection and quantitative analysis. Recently, the development of high-resolution broadband sum-frequency generation vibrational spectroscopy (HR-BB-SFG-VS) with sub-wavenumber resolution generated by synchronizing two independent amplifier lasers have opened new opportunities for probing an intrinsic SFG response. Here, we present a new flexible approach to achieve HR-BB-SFG-VS. In this system, two regeneration amplifiers shared the same oscillator laser as the seed, and a time-asymmetric visible pulse with a nearly Lorentzian line shape filtered by an etalon was used to overlap with a femtosecond broadband infrared pulse. This Lorentzian line shape of the visible pulse can greatly simplify the spectral fitting and analysis. We also demonstrated that the single-sided long visible pulse provided both high spectral resolution (1.4 cm-1) and effective suppression of the non-resonant background by detuning the time delay between visible and infrared pulses in SFG-VS measurements. With this new SFG setup, a pair of spectral splittings by 3.1 ± 0.7 and 3 ± 0.2 cm-1 for the symmetric and antisymmetric stretching of the CH3 group was resolved at the CH3CN/TiO2(110) surface, which are tentatively attributed to two different orientational methyl groups. These technological advancements can help broaden the applications of HR-BB-SFG-VS and provide solid ground for a better understanding of complex molecular structures and dynamics at interfaces.
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