Multireflection Sum Frequency Generation Vibrational Spectroscopy

We developed a multireflection data collection method in order to improve the signal-to-noise ratio (SNR) and sensitivity of sum frequency generation (SFG) spectroscopy, which we refer to as multireflection SFG, or MRSFG for short. To achieve MRSFG, a collinear laser beam propagation geometry was adopted and trapezoidal Dove prisms were used as sample substrates. An in-depth discussion on the signal and SNR in MRSFG was performed. We showed experimentally, with 'm' total internal reflections in a Dove prism, MRSFG signal is similar to m times that of conventional SFG; SNR of the SFG signal-to-background is improved by a factor of >m(1/2) and