Simplified sum frequency generation using a narrow free-spectral-range etalon.

We report the implementation of a narrow free-spectral-range Fabry-Perot etalon for multiplex vibrational sum frequency generation (VSFG) spectroscopy. Moreover, we demonstrate the use of the etalon reflection to simultaneously generate a broadband infrared pulse, which enables a multiplex VSFG spectrometer using a total of 0.58 W. VSFG spectra with and without a nonresonant-suppressed background were simultaneously collected utilizing time asymmetry in the upconverting pulse. Two examples are demonstrated in which spectral perturbations can be induced by the time-asymmetric pulse even without nonresonant suppression.