​​A powerful probe of interface molecules

Infrared-visible sum frequency generation (IR-Vis SFG) is a surface selective vibrational spectroscopy. As such, it is a powerful probe of the structure, interactions and chemistry of interface molecules between all phases - solid, liquid or air and can be usefully applied to a wide range of problems in fields such as catalysis, structural chemistry or photovoltaic device research.  

IR-Vis SFG spectroscopy is under continuous development at the Ultra facility.¹ Currently on offer is a dedicated spectrometer, with built-in flexibility for different optical configurations (e.g. normal reflection or ATR) and different sample-types. The spectrometer uses as standard broad bandwidth IR pulses (> 400 cm^-1, 50 fs) and etalon narrowed time-asymmetric  1-2 ps 800 nm pulses (giving non-resonant background suppression).

There are many interesting directions in which to develop the IR-Vis SFG technique – imaging, time resolved (ms-s and ultrafast) and two dimensional infrared. The 20W 10 kHz Ti:Sapphire laser system driving the experiment allows multiple OPAs to be driven and an IR pulse shaper is available for spectral filtering and two-dimensional SFG spectroscopy.

Selected recent publications

• Neri et al. 2018.  10.1038/s41929-018-0169-3
• Neri et al. 2017.  10.1021/jacs.7b06898