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[摘要]：We describe an ultrabroadband IR-visible sum-frequency (SF) setup that allows simultaneous acquisition of the entire vibrational spectrum of water molecules at mineral surfaces in the OH stretching region without ever tuning the IR laser pulses. Our newly developed 800-nm pumped noncollinear optical parametric amplifier (NOPA) generates broadband mid-IR pulses (similar to 1800-3500 nm, or similar to 2900 - 6000 cm(-1)) with bandwidths >600 cm(-1) at half-maximum at near 3500 cm(-1). Using the ultra-broadband IR NOPA, we constructed a sum-frequency vibrational spectrometer that allowed the acquisition of spectra of the OH stretches of water at hydrophilic and hydrophobic silica surfaces, over the frequency range similar to 2900 - 3800 cm(-1), within 60 s, much shorter than with scanning SFG spectrometers. The ultra-broadband SFG spectrometer reported here can be potentially applied to time-resolved measurements of kinetics at interfaces. (C) 2011 Optical Society of America |
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