We have developed a novel ultrabroadband optical parametric amplifier that generates infrared pulses in the ~2800-6000 cm1 range bandwidths >2000 cm-1 in the near-IR range. Pulse front tilt of the OPA output has been corrected, allowing for compression of signal pulses down to 25 fsec.  These ultrabroadband IR pulses allow us to perform SFG spectroscopy of silica/water interfaces, extending from ~2900 cm-1 to ~3800 cm-1, over the entire frequency range of OH stretch simultaneously (�in one shot�), without tuning the OPA.  The high signal-to-noise ratio of our spectroscopic setup has allowed us to study low-intensity features in detail, including:1) non-hydrogen bonded OH vibrations at hydrophilic silica/water interfaces;2) combination [stretch+bend] bands of water at the silica surface appearing at ~5000-5200 cm-1.3) Overtones of water stretching modes at silica/water interfaces.

Ultra-broadband vibrational sum-frequency spectroscopy of mineral/aqueous interfaces

243rd National Meeting (2012)

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