Balanced-detection Raman-induced Kerr-effect spectroscopy

We introduce balanced-detection (BD) Raman-induced Kerr-effect (RIKE) as a powerful coherent Raman scattering (CRS) technique. RIKE relies on the Raman-induced birefringence that occurs when the pump-Stokes frequency detuning is in resonance with a vibrational transition. We show how a balanced-detection configuration, inspired by that applied in electro-optic sampling, suppresses both the linear and nonlinear backgrounds that affect other CRS techniques. BD-RIKE enables homodyne amplification of the signal and linear dependence on the concentration of the target oscillators, as well as cancellation of laser intensity noise. In addition, it allows straightforward selection of either the imaginary or the real part of the nonlinear vibrational response.