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Flexible approach to vibrational sum-frequency generation using shaped near-infrared light...

Publication Type
Journal Name
Optics Letters
Publication Date
Page Numbers
2038 to 2041

We describe a new approach that expands the utility of vibrational sum-frequency generation (vSFG) spectroscopy using shaped near infrared (NIR) laser pulses. We demonstrate that arbitrary pulse shapes can be specified to match experimental requirements without the need for change to the optical alignment. In this way, narrowband NIR pulses as long as 5.75 ps are readily generated, with a spectral resolution of about 2.5 cm-1, an improvement of approximately a factor of 3 compared to a typical vSFG system. Moreover, the utility of having complete control over the NIR pulse characteristics is demonstrated through non-resonant background suppression from a metallic substrate by generating an etalon waveform in the pulse shaper. The flexibility afforded by switching between arbitrary NIR waveforms, at the sample position with the same instrument geometry, expands the type of samples that can be studied without extensive modifications to existing apparatus or large investments in specialty optics.